[HN Gopher] Got called to a professor's office after a complaint...
___________________________________________________________________
Got called to a professor's office after a complaint his SPARC4 was
running slow
Author : luu
Score : 781 points
Date : 2023-07-25 03:00 UTC (20 hours ago)
(HTM) web link (infosec.exchange)
(TXT) w3m dump (infosec.exchange)
| gnoack wrote:
| In the mid-2000ds, there eventually came a time when the xlock
| (Ex-lock) screen locker disappeared from the last university
| workstations that still had it. People routinely got puzzled when
| they could not run it. It was a fun prank to tell them that Ex-
| Cee-lock was the replacement for it (which would, of course, run
| the clock application). :)
| mcv wrote:
| Xlocking workstations became a problem at our university.
| People would claim a workstation, lock it, go do something else
| (lunch, lecture) and then come back to their reserved
| workstation. So the admins added a button that you could log
| someone out if the screen had been locked for more than half an
| hour.
|
| They didn't want to ban xlock because they cared about
| security.
| yomlica8 wrote:
| In high school I'd reserve workstations for my friends by
| unplugging the keyboard. The PC would fail to boot with
| "Keyboard not found, press F1 to continue" which was enough
| to get it designated broken and avoided.
| LoganDark wrote:
| > Keyboard not found, press F1 to continue
|
| I don't know why this is so funny. Probably because it's a
| catch-22 since you need a keyboard anyway in order to press
| F1.
| alexjm wrote:
| It's a poorly worded message, but the idea is that you
| press F1 after plugging in (or otherwise fixing) the
| keyboard.
| jweather wrote:
| I did this unintentionally in college once by switching the
| keyboard layout to Dvorak, which for some reason persisted
| across logins. I came back later that day to the same lab
| and the station I had been using was marked "Out of Order".
| Huh, that's weird. Sat down at the station next to it. Next
| day both of them were marked "Out of Order". Oh, huh. Is
| there something weird with the keyboard? I might know what
| happened...
| dspillett wrote:
| _> So the admins added a button that you could log someone
| out if the screen had been locked for more than half an
| hour._
|
| In our CS labs the PCs re-imaged themselves on boot0, from a
| choice of OS images1, so you didn't have to worry about
| causing corruption of the machine by just power-cycling it to
| get around the locked status. This meant that locking a
| workstation to reserve it didn't work.
|
| My workaround to that2 was to set the wallpaper which
| displayed behind the unlock prompt to an image of a
| bluescreen indicating a hardware error and move the window
| containing the lock prompt to the for bottom right of the
| screen, so it was just a single pixel and not easily noticed.
| Hey presto: a locked machine that no one wanted to claim by
| restarting because it looked faulty. Obviously anyone with
| half a brain watching me unlock the machine a short while
| later would immediately work out the trick, so the knowledge
| spread soon enough and the ruse stopped being as effective.
| It was very effective for a while.
|
| --
|
| [0] from the same shared network drive, which was initially a
| problem (this was the first year that lab had been in
| operation) if several machines re-imaged at the same time as
| head thrashing caused IO throughout to fall through the
| floor. Later revisions of the setup helped by tweaking cache
| settings, and giving the server more RAM, so that the second
| and subsequent read of an image in a given period would come
| from cache, also the images were compressed for the same
| reason and also to reduce the second bottleneck: the glut of
| traffic through the server's single 100mbit NIC.
|
| [1] usually just Windows NT and the local Linux build, but
| sometimes other options were present
|
| [2] which I used very occasionally, partly to not be a dick
| but mainly so as to not give the game away to quickly
| Trixter wrote:
| In high school in 1988, a friend and I discovered a vulnerability
| in the netware deployment of 30 IBM PS/2 Model 30-286s in our
| brand new computer lab that allowed us to insert programs into
| the autoexec netboot sequence. Prior to that, we'd been hacking
| on the (brand new at the time) VGA registers and figured out how
| to switch from 80x25 text mode to 320x200 256-color graphics mode
| with no flicker or glitches, as both modes have a refresh rate of
| 70Hz. So he created a TSR that preloaded a digitized picture of a
| clown face (a popular upload on BBSes at the time) into
| A000:0000, and after about 4 minutes, it would display the clown
| face for a few frames and then immediately switch back to
| whatever the user was working on. We gave ourselves away because
| we couldn't stop laughing in the corner of the room watching all
| the students get very confused/horrified looks. One bonus was the
| comic timing of a student calling the instructor over, having him
| stare at the screen for 3+ minutes, turn away, then have the
| clown face flash when he wasn't looking.
|
| My friend's name was Brian, one of the smartest people I've had
| the privilege of knowing. Ten years later, we created
| mobygames.com.
| LorenPechtel wrote:
| My gag was a bird chirp that would play every so often--
| typically minutes between chirps. There were several random
| numbers that went into making the chirp so it would be
| different every time and every noise it made would be shifting
| frequency, never a moment of a fixed tone (back when speakers
| usually just went BEEP.) Leave it running on a machine that
| wasn't being used...
| daly wrote:
| IBM 370 mainframe, 80+ programmers, running VM/370 which creates
| virtual machines, one for each programmer. I'm one of two systems
| programmers with "superuser" privs.
|
| In the virtual machine you normally ran CMS but you could run
| anything. Some machines ran MVS.
|
| To direct a command to the virtual machine itself you would
| prefix the command with a special character which by default was
| # but any chosen character could be the magic prefix. So #cp ...
| would be a command to the virtual machine.
|
| Bored one day I wondered if a virtual machine could run VM
| itself, on the "second level". I booted it up, changed the prefix
| character to ! (so, !cp). I could create new virtual machines
| inside this new VM.
|
| So, could a second level virtual machine run VM? I booted it up
| on the "third level", changed the prefix to @ (so, @cp)...
|
| I got 8 levels deep. So, yes, VM could run VM, could run VM,
| could run VM... etc.
|
| Game over. Time to start shutting down these embedded levels.
|
| Out of habit I typed "#cp shutdown" ... and it did. The REAL VM
| on the REAL machine shut down. Panic run to the machine room to
| push the start button on the console.
|
| Of course the system keeps a log ... and the other systems
| programmer showed up at my door ... and said "don't do that
| again".
|
| Fun times.
| rwmj wrote:
| I wrote this for abusing qemu in the same way:
| http://git.annexia.org/?p=supernested.git;a=summary
| Neil44 wrote:
| When I worked in IT at a big company we had a fake screensaver
| that emulated a blue screen and boot loop situation. Nobody ever
| thought to press a key or move the mouse which would have cleared
| it, they would always go for a power cycle followed by lots of
| hilarious troubleshooting, before it happened again and again.
| Good times.
| 1vuio0pswjnm7 wrote:
| For text-only browser users:
|
| https://infosec.exchange/@paco/110772422266480371/embed
| raverbashing wrote:
| You mean for the poor people that don't have an X capable
| terminal and only have a VT100
| hulitu wrote:
| I don't even have a VT100. I have an Android phone.
| EgregiousCube wrote:
| Sort of a meta-comment about infosec.exchange, so I expect a few
| downvotes, but while this was a funny dad joke it took more
| scanning and reading than it was worth. Mastodon UI's are very
| dated despite being new. I miss interdepartmental unix pranks!
| rblatz wrote:
| I tried to read it and it was unusable. I had to turn on reader
| mode to make it at all usable.
| o1y32 wrote:
| This thing has a side bar even on a mobile device which shrinks
| the width of the text even more. The text is very difficult to
| read. You have to acknowledge that Twitter is a carefully
| designed and mature product at least in terms of UX.
| devin wrote:
| I wrote some code to run on the office computer that we used to
| stream music from. At a random time every 24-48 hours, it would
| turn its volume up and say "I love you" using the Mac OS whisper
| voice.
| guerrilla wrote:
| Ahh, I miss AppleScript and those voices...
| dzdt wrote:
| A grad school prank one of my friends pulled on another:
| echo sleep -1 >> .login
|
| was appended to the .login file of the victims account. The
| victim stepped away from the terminal briefly leaving themselves
| logged in allowing the prankster to make the addition. It was
| days later with over 20 sleep statements appended before it was
| apparent that something was uniquely wrong with that student's
| login. Day after day the victim grew increasingly frustrated with
| the slower and slower times from initial login to active
| terminal. Finally when it was getting unbearable the prank was
| discovered.
| kwantam wrote:
| Came here to reminisce about the same trick :)
|
| After a while we decided that adding one second per login was
| too subtle... echo "echo sleep 1 >> ~/.login"
| >> ~/.login
| NoZebra120vClip wrote:
| Good news! Now that "sleep" supports fractional seconds, you
| could ratchet up the suspense verrry slllowly...
| fit2rule wrote:
| [dead]
| awiesenhofer wrote:
| And here I thought for a second this would be a story about a
| professor who still uses an old SparcStation today...
| heelix wrote:
| Back in the day when a 4x CD-ROM burner was a luxury, we got a
| phone call from a customer we shipped a CD to. Would not read.
| Did a second burn at 1x speeds, tested on several machines, and
| mailed out the disk. Would not read. Burned a third and tried on
| every unique setup we could find on the most premium disk we
| could buy. Would not read.
|
| I drove out to do the manual install a stack of media in hand.
| Got to the customer site - and watched in horror as they put the
| CD-ROM in the 5.25" floppy drive. It fits.
| datenwolf wrote:
| If you really, really want to ruin an X11 session, I got you
| covered:
|
| https://git.datenwolf.net/codesamples/tree/samples/X11/x11at...
| g051051 wrote:
| Someone at work played this prank on a business analyst and
| almost got fired. It was the early 90's, and we were a shop
| running HP/UX on Apollo workstations. She was a SME for the
| application we were developing, but was otherwise non-technical.
| He and her were friends, so one day he fired up xroach on her
| system. When she moved a window she absolutely freaked out, and
| wanted the guy fired. He kept his job, but I don't think they
| were friends after that.
| NoZebra120vClip wrote:
| Plenty of people in this thread with Apollos in their past. We
| had no fun on the Apollos in college; they ran DOMAIN/OS, I
| programmed the 68xxx assembly and I got out of there.
|
| I did all my mischief on the Unix machines: 3B2s with dumb
| terminals, and diskless SPARCstation SLCs.
| ggm wrote:
| In some ways it was a sw bug: the roaches should have been more
| apparent, not simply breeding.
| maxbond wrote:
| Friends don't let friends merge code that consumes resources
| without bounds.
| silisili wrote:
| True. In reality once they started crowding they'd have started
| scrambling in the open.
| pmontra wrote:
| I remember a variant of xroaches: it had crawling babies with
| diapers. Maybe they wouldn't multiply under windows but they
| could be just a different bitmap with the same algorithm.
| rwmj wrote:
| xneko was the best one.
| n6h6 wrote:
| I looked it up, and aww :)
|
| https://en.wikipedia.org/wiki/Neko_(software)
|
| Unlike many of the things people talk about on this website
| that I didn't experience growing up, I actually did download
| this on Windows Vista once. It might have been a version with
| malware, but I don't remember.
| ragebol wrote:
| Wanted to install xroach on my Ubuntu box, but no apt package is
| available.
|
| There is xroachng though [0], created by: Willem_ _vermin_ :-)
|
| [0] https://sourceforge.net/projects/xroachng/
| codewiz wrote:
| No Wayland version yet?
| pavon wrote:
| From what I understand this would have to be built into the
| compositor, as it is the only process that knows the
| positions of all the windows.
| alexeiz wrote:
| It's available in openSUSE repos. Just saying...
| lordgrenville wrote:
| Looks pretty easy to compile
| https://github.com/interkosmos/xroach
| ragebol wrote:
| Yep, couldn't be easier. It's been running on my box since I
| left my comment. No bugs observed yet, maybe they are hiding
| too well
| Gordonjcp wrote:
| [dead]
| p0d wrote:
| Must be 20 years ago as Google was a thing and we had a split
| monitor and kvm with the one computer in the school IT classroom.
|
| My colleague types hello into the Google search box from the next
| room. The student then typed who's this? Colleague types, Jimi
| Hendrix...student turns computer off at the plug :-)
| nathell wrote:
| Ah, the golden student days of yore.
|
| Mine were in the early 2000s. Back then, the computers at the lab
| at my uni were not very powerful, so people would do work at a
| Linux console, saving themselves the hassle of running a bulky X
| session.
|
| Some time around 2001 I read the console_ioctl(4) manpage and
| found it replete with prank possibilities. I wrote little
| programs that would flip the console font so that all the
| characters were upside down; or swap capital letters with small
| letters, again by way of manipulating the font; or flash patterns
| on the keyboard LEDs; or fade to black and back by manipulating
| the palette.
|
| I then added a server component so that I could leave it running
| at an innocuously-looking terminal, wait for a victim, fire up
| these effects remotely from another box in the same room, and
| watch what happens. Fortunately, I soon discovered that the
| coding part was more fun than the watching-people-slip part, so I
| gave up on the latter.
|
| Another prank I used to do was simulate a successful root login
| on these terminals by just typing in what would be printed,
| including the motd, at the getty login prompt, simulating
| newlines with tabs/spaces (and never ever pressing RET), ending
| in `[root@mailhost root]# `. Then, again, step back and watch
| what happens. Some people would curiously type in `whoami` and be
| puzzled why they got a password prompt; some would step back in
| terror without touching anything, switch terminals and email the
| sysadmin.
| 0x6c6f6c wrote:
| I wish I'd had Linux systems. I was doing the same type of
| thing with Windows networks since you could effectively run any
| program as any user with task scheduling so long as they were
| logged into the system. Pair that with active directory and you
| have user info. So knowing who was where, open iexplorer at
| certain site, innocuous word doc, etc. The most malicious case
| was an automated logout batch script.
|
| People eventually caught on to the approach and tried to
| replicate the remote execution but executing as themselves
| instead of that user so when the IT admins came around there
| was a very obvious trail to who had been running it. I stopped
| playing around but eventually IT then SWE became my profession.
| I sometimes wonder how it'd have gone if I'd been reprimanded
| though.
| xolve wrote:
| This certainly sounds fun! This is how people realise coding is
| immensely fun and impactful when you are involved in the
| results :)
| lizknope wrote:
| The xroach man page has some options that not everyone knows
| about
|
| Turn on -squish and set the -rgc (roach gut color) and you can
| make your screen look disgusting! It was great in college in the
| mid 1990's
|
| Then there were the jokes about "SEE ALSO" for xroachmotel and
| xddt
|
| https://manpages.opensuse.org/Tumbleweed/xroach/xroach.1x.en...
|
| -rc roach_color Use the given string as the color for the bugs
| instead of the default "black".
|
| -speed roach_speed Use the given speed for the insects instead of
| the default 1.0. For example, in winter the speed should be set
| to 0.1. In summer, 2.0 might be about right.
|
| -roaches num_roaches This is the number of the little critters.
| Default is 10.
|
| -squish Enables roach squishing. Point and shoot with any mouse
| button.
|
| -rgc roach_gut_color Sets color of the guts that spill out of
| squished roaches. We recommend yellowgreen.
|
| SEE ALSO
|
| xroachmotel(1), xddt(1)
| password4321 wrote:
| In my case a professor took a lab PC for their office, but the
| script to shutdown all the lab computers every night wasn't
| updated...
| frellus wrote:
| The other trick, aside from xroach, we would play on professors
| would be to take a screenshot of their desktop and re-display it
| as their wallpaper, with windows opened and all. To see a
| professor close an app window and still see it on the screen
| (from behind where it was) and to try over and over futilely to
| hit the "x" to close it on X Windows was a beautiful sight.
|
| It wasn't _our_ fault professors typically ran "xhosts +" in
| order to make their lives easier.
|
| Source: my 25 year-ago mischievous self ... Sparc. Miss those
| days.
| m463 wrote:
| I remember lots of things like this, from the sunos days.
|
| There was a program that would sort of melt your screen.
|
| There was another one that would animate a little character at
| the bottom who would then push your desktop off the side of the
| screen.
|
| and there was a way to take all the workstations in the group,
| and play sounds on them.
|
| So (nearest I can vaguely recall): for i in
| machine1 machine2 machine3 ... do rsh $i "play
| applause.au &" done
|
| sunos came with sound files for laughter and applause, and it was
| amusing to have all the machines in the group laugh or applaud
| like a crowd.
|
| (well it was amusing the first few times anyway...)
| lakkal wrote:
| We had some Apollo Domain machines at school which could also
| run similar programs - I remember 'Crumble' and 'Melt' being
| two of them. And you could run them on other peoples' display.
| So we used to melt/crumble the screens of the engineering
| students in the next lab over. 'We' in this case had admin
| privileges, though, and only did it a couple of times.
| AnimalMuppet wrote:
| > There was a program that would sort of melt your screen.
|
| This existed for PCs, too. It was called "drip". When idle,
| individual characters would "drip" down your screen like
| raindrops, at random times, for random distances.
|
| Another one I remember was "drain". In the very early PC days,
| you could add this program to the AUTOEXEC.BAT of an
| unsuspecting victim's computer, so that it would run at
| startup. It would start flashing "SYSTEM ERROR 0304-B" for a
| moment, then add "Water detected in disk drive A:". Another
| moment, then "Now draining", and it would play this gurgling
| sound out of the speakers (as best you could, on the speakers
| of the original PC). That would peter out, then "Now starting
| spin dry cycle", and it would play this whining sound for a
| bit, ramp that down, and then tell you that it was OK to use
| the system now.
|
| In those days, there weren't "logins" to PCs. If you saw a PC
| without the normal user present, you could do _anything_ to it.
| Starwatcher2001 wrote:
| I seem to recall that "Drain" spun up the motor on the floppy
| drive to create the spin dry cycle.
| AnimalMuppet wrote:
| If I recall correctly, the drive light stayed on, the drive
| was spinning, but the whine came from the speakers, and
| moved to a higher pitch partway through. It also smoothly
| ramped down in "RPM" (frequency) at the end, which is not a
| thing that the floppies could do.
| m463 wrote:
| PCs always had better stuff. I remember (fondly?) the After
| Dark Totally Twisted screensavers.
| lizknope wrote:
| If someone xhosted my machine I would run xmeltdown back to
| their display. I wrote in another post in the thread about how
| and why someone would xhost my machine.
|
| https://github.com/veltzer/xmeltdown
| mcguire wrote:
| Largely unrelated, but I was told once by a senior sysadmin
| that I was never, ever to send an email with the Open Firmware
| song attached to it.
|
| https://youtu.be/b8Wyvb9GotM
| pjmlp wrote:
| On our university lab, the main reason why most of the savy users
| would have "xhost -" on their login scripts would be to avoid
| being shown not so convenient images at the wrong times.
| bluedino wrote:
| Back in my MSP days I had a client report that their server was
| slowing down after an hour. They would also use this "server" (a
| tower computer in a back room) to adjust inventory, print
| reports, etc, but after an hour of having used it, everything
| would slow to a crawl. It was running databases and such that
| other computers in the building accessed.
|
| Every time the server slowed down, someone would go back there
| and restart the software, or reboot the whole computer, and it'd
| be fine for another hour.
|
| Sure enough, after an hour, some fancy ass 3D screen saver came
| on and pegged the CPU. It was some shareware thing that someone
| downloaded because it looked cool. I ended up turning the
| screensaver off and just set the monitor to go to sleep after 10
| minutes.
| yjftsjthsd-h wrote:
| It's funny how many stories from earlier times boil down to "it
| wasn't meant to be malicious, just funny, but people didn't
| realize that it would multiply that much or use so many
| resources". See also: the morris worm (I mean, that arguably
| _was_ designed as malware, but supposedly wasn 't supposed to be
| nearly as bad as it was)
| Reason077 wrote:
| Guy is still running a SPARC4? In 2023? No wonder it's slow!
| phs318u wrote:
| Back in 1989 I worked as a one-man-IT-department for a bunch of
| ex-academic economists doing econometric modelling on a Digital
| VAX 11/750. This mini-computer was running VMS - a multi-user
| operating system. All users had admin rights and each one thought
| that they could make their models run faster by bumping up the
| process priority as far as it could go - which of course
| interfered with the realtime processes needed to manage the
| effective running of the computer. Unsurprisingly, this had the
| opposite effect to what they intended. When I discovered this was
| what was happening, I revoked their privileges and after a system
| restart, sanity was restored. I was thanked for finally making
| the system work faster.
| ycombinete wrote:
| Great example of the economic principle _The Tragedy of the
| Commons_ :
| https://en.m.wikipedia.org/wiki/Tragedy_of_the_commons
| ww520 wrote:
| Economy is all about incentives and behaviors. Did they learn
| any lessons from how they acted during the episode? And
| hopefully published a whole bunch of papers from it?
| jjp wrote:
| Had exactly the same with a bunch of developers who could
| change the queue priority on a mainframe for their own work.
| They couldn't work out for themselves that if everybody set
| their work to the highest priority it had no benefit to any of
| them. Trying to educate them failed, so we revoked access.
| darkclouds wrote:
| > All users had admin rights and each one thought that they
| could make their models run faster by bumping up the process
| priority as far as it could go - which of course interfered
| with the realtime processes needed to manage the effective
| running of the computer
|
| It amazes me what the bios and OS or OS api's let you do, even
| on modern devices.
| LoganDark wrote:
| > It amazes me what the bios and OS or OS api's let you do,
| even on modern devices.
|
| Same, but not necessarily in a negative way. I like pushing
| my hardware and software to the limits, becoming unable to
| push those limits would be pretty disappointing.
| Kon-Peki wrote:
| I'm not sure anyone should call VMS "modern", but that's
| beside the point ;)
|
| VMS has a very comprehensive system of quotas and limits,
| so a "properly" configured system wouldn't suffer those
| issues.
|
| And furthermore, VMS isn't intended to be used
| "interactively" as such. You should be submitting work to
| the built-in batch queues - each with various attributes
| that can include the priority level. This allows the system
| to intelligently manage work based on a comprehensive view
| of the entire system - something a single user in a multi-
| user system can't have. If you like pushing a multi-user
| system to its limits, you'd be impressed with what VMS
| could do even way back in the 1990s.
| infostud wrote:
| I remember going along to a VAX/VMS System Administration
| workshop. Another bloke and I did a prank where we substituted
| text of the text editor that would produce blinking "Working"
| if it got busy. We substituted "or" with "an". The workshop
| coordinator caught us because we forgot to do something I can't
| remember and a login was tied to the change in the executable.
|
| Happy System Administrator's Day!
| latchkey wrote:
| Oh, my first internet access was through one of those in 1991
| at college! Found a cool exploit that let me anonymously
| broadcast messages to anyone. Sure freaked out a lot of people.
| Was fun cause you'd get to see the effects of your action in
| real time because it was a bunch of people in the same room on
| shared terminals.
| pdntspa wrote:
| Reminds me of WinPopup spam on Windows 95
| cheese_van wrote:
| Around '84 doing seismic data. We just got a terminal in the
| office that would allow you to monitor the jobs running on
| the IBM mainframes downstairs. Completely new tech to all of
| us. It had a command line message capability. Because it was
| quite easy to send to all instead of just your recipient, one
| marriage ended rather suddenly. Seeing the effects of your
| actions with new tech in real time indeed.
| sokoloff wrote:
| Working at a hedge fund with multiple locations, the
| founder insisted that mail to "staff" would reach everyone
| at the local office and mail to "all" would reach everyone
| (in all offices).
|
| One afternoon (in the middle of the trading day), we got a
| weird email with an empty body and a bunch of nonsense
| email addresses. Turns out some poor trader wrote an online
| dating email, but pasted/wrote the mail in the cc line,
| resulting in all of us learning that he thought "you don't
| seem like all the other girls", which was sent to you@,
| don't@, seem@, and the dreaded all@.
| joshjje wrote:
| Nice, reminds me of my high school computer lab. I wrote a
| trojan horse in VB6 and distributed it among the lab PCs
| somehow, then from mine I would open and close peoples CD
| trays, turn their monitor off, send them to... questionable
| websites where they would swear it wasn't them! Haha, good
| times.
| FractalParadigm wrote:
| A friend and I were able to phish passwords from nearly the
| entire school we went to with VB6 - the school (board) used
| active directory for logins on a shoddy network where some
| switches would often just drop all traffic to a random port
| for any length of time, meaning a PC would lose connection
| to the AD server at random. The kicker was that attempting
| a login after the connection was dropped greeted you with a
| "could not connect to //SCHOOL_BOARD//SCHOOL_NAME/PC_NAME"
| to which the solution was reboot the PC and it would work
| again (99% of the time, anyways). The other kicker was the
| background image and login domain were the same for every
| single computer at a single school. We exploited this; we
| created a full-screen/un-exitable UI with the same
| background image behind a form simulating the normal login
| screen. We would first login to our own account and run the
| program (there were no login limits either), at which point
| someone else later through the day would sit down and try
| to login. The credentials that got typed in were added to a
| .txt in my own user folder before the user rebooted the
| "non-functional" system. Of all the dumb shit we did,
| that's probably the only thing we never got caught doing,
| and probably because we never did anything nefarious with
| them.
| taneq wrote:
| "Cool exploit"? Like net send? :)
| KnobbleMcKnees wrote:
| I was banned from the school computer suites several times
| for (ab)using net send. Good times.
| adenner wrote:
| I remember someone getting a bit wild with their netsend
| and accidentally spamming the entire school district,
| including the administration. We also found out that you
| could DoS your instructor with enough messages.
| myself248 wrote:
| On our high-school network, the Guest account had NET
| SEND privileges. It was somehow less chaotic than one
| might expect.
|
| We had a single shared T1 pipe for the whole district.
| Which was enough for email and stuff, but when web
| browsers got popular, it was suddenly woefully
| inadequate.
|
| So I figured out I could NET SEND * SERVER ROOM POWER
| FAILURE - 9 MINUTES OF BATTERY REMAIN - SAVE YOUR WORK
| AND LOG OUT and after a flurry of traffic, the network
| fell to nearly-idle. I could max out the T1 with whatever
| I needed to do for a few minutes, then NET SEND * SERVER
| ROOM POWER RESTORED and nobody would be the wiser.
|
| The admin did go check on the "flaky UPS" a few times
| before looking closely at the message. Had a good laugh
| and told me not to use it too often.
| fullstop wrote:
| I was able to use samba to generate these messages such
| that they looked like they came from other users in the
| lab. We had a lot of fun with that.
| gadders wrote:
| I remember in the mid to late 90's when you could get spam
| from outside of your network via net send. Happy days...
| jethro_tell wrote:
| Wall
| em-bee wrote:
| the key "feature" of the exploit was the ability to send
| messages anonymously. the unix commands "write" and "wall"
| allow you to send a message to any users terminal.
|
| apparently "wall" has a switch "-n" to hide the sender
|
| https://unix.stackexchange.com/questions/99460/sending-
| messa...
|
| for windows there was "net send" which could be exploited
| by a tool called NetSendFaker, but this was 1991, so i
| doubt that already existed.
| idontwantthis wrote:
| If a group of economists can't coordinate their behavior to
| prevent tragedy of the commons then they should rethink their
| career and life choices.
| zer8k wrote:
| A group of economists couldn't coordinate splitting a bill at
| Applebee's.
| yabbs wrote:
| Applebee's... Does not compute.
| hgomersall wrote:
| On the contrary, it was a rational attempt to limit their
| ability to break things.
| dghughes wrote:
| That reminds me of a story from a guy I worked with.
|
| I'm not sure where he worked but it involved a queue of people.
| He said someone asked him if they could be given priority for
| their problem to be looked at before others in the queue. In
| other words jump to the head of the queue.
|
| He said "Sure!" to the surprise of the person asking "But you
| do realize I will do that for anyone else who asks the same
| thing?"
|
| So they person chose to remain in their place in line.
| shagie wrote:
| There was a system that a bunch of students administered (I was
| one of the students at the time). We would occasionally prank
| each other. On this DEC station where memory was scarce, one
| guy ran emacs.
|
| Another guy wrote a program that forked 1000 copies of itself,
| nice itself to 19, did a sleep(0) and then exit. As soon as it
| got _any_ cpu time, it would exit, but it never would as long
| as emacs was running. Meanwhile, the load (as displayed by
| xload) became a solid black box.
|
| So the emacs guy would run 'ps -ef | grep procname | xargs
| kill' as root.
|
| This meant that it had to get some cpu time to handle the kill,
| which took longer than a sleep(0) and was largely ineffective.
|
| The second time this prank was done, the process was named
| 'ema'... which promptly also killed all instances of emacs too.
|
| The third time this prank was done, the process was named 'et'.
| This happened to have also matched /etc/initd and the machine
| rebooted rather suddenly.
| arethuza wrote:
| We used to play pranks on each other such as logging into the
| NeWS server on a colleagues machine and manually setting a
| small rotation in the transformation matrix for a terminal
| window that someone was typing in....
|
| NeWS had an interactive PostScript shell and almost no
| security so this kind of mucking about was trivial...
| jfk13 wrote:
| Ah, good times.... we used to do similar things across the
| HP Apollo workstations at the place where a friend of mine
| worked (and I unofficially "borrowed" computing facilities
| for a project of my own -- though I did also contribute a
| substantial speed optimization to their main product, so
| nobody seemed to mind).
| gcr wrote:
| For april fools' day, on my first job as a troublesome
| ~16-year-old administering our university lab's firewall
| (academia was a different land when it comes to trust), I
| set up some automatic network-wide substring replacement
| filters for incoming HTTP responses to replace `<body` with
| something like `<body style="transform: rotate(0.1deg);"`.
| This was in the time before HTTPS was ubiquitous, so it
| worked on most websites.
|
| Unfortunately, it broke some pages that lab users needed
| for school. I later learned one colleague wasn't able to
| complete a homework assignment because of my prank.
| crest wrote:
| The joy of running Upside-Down-Ternet as transparent
| proxy on April Fool's day.
| Aperocky wrote:
| "occasionally"
| shagie wrote:
| Occasionally. It wasn't a daily, or even weekly occurrence.
| But, in all honesty those pranks were some of the things
| that helped my early sysadmin experience.
|
| When you have nice, well behaved users you'll not have
| problems that need solving. When things go awry - that's
| when you'll need to solve problems... sometimes even
| without pranks.
|
| Before we had yp set up on the machines, we just copied the
| password file between them with a note "make sure you
| change your password on foo" since that was the one we
| regarded as authoritative and would copy that to bar.
|
| One time, while adding a person to the /etc/groups file for
| write access to the web server, someone did rcp /etc/groups
| bar:/etc/password (I suspect it was muscle memory) and,
| well, now bar was unhappy and wouldn't let anyone log in...
| or even su to root to fix it. Found someone who had an open
| terminal and had them do a while 1 sync... and then powered
| the machine down and brought it back up. It wasn't happy,
| so started up in single user mode. Just needed to get the
| password file in there... but the terminal was 300h which
| didn't have a proper termcap entry for vi or emacs to work.
| I was a mudder and knew how to use ed... so ed
| /etc/password and then the contents of the minimal password
| file were dictated to me. When done, we got it back up and
| then copied the password and groups files to the proper
| spots.
|
| Another time (and this was a prank), someone left
| themselves logged in and someone else created a directory
| path that was about 3000 characters long. /user/jsmith/I/wi
| ll/not/leave/myself/logged/in/I/will/not/leave/myself/logge
| d/in/ ... The problem with this is that `rm -rf` won't
| handle paths longer than 2048 characters long. So it didn't
| get removed "I'll do it later." You know what else doesn't
| like paths longer than 2048 characters long? fsck. So when
| the machine was rebooted/crashed at some point, the root
| volume (yea, user directories were on the root volume)
| failed to fsck... and failed to mount. Stuck in single user
| mode with the backup partition and reading the man pages
| for mount on the other machine we found how to force a
| mount without fsck and then had the guy who did the
| extremely long path fix it (and promise not to do it again)
| and got machines working.
| schoen wrote:
| Somehow I've never considered what will happen on Unix if pid
| 1 exits!
|
| Even though I'm pretty sure I've run with init=/bin/sh and
| then typed "exit" at some point in my single-user session, I
| have absolutely no recollection of the results. I should try
| it on a few OSes and see!
| suid wrote:
| If PID 1 exits, the system usually panics immediately and
| restarts.
| rzzzt wrote:
| "Attempted to kill init!" https://github.com/torvalds/lin
| ux/blob/0b5547c51827e053cc754...
| rollcat wrote:
| "...and that's why we have to put half a million lines of
| C in PID 1"
| NikkiA wrote:
| i'm reasonably sure that kill -1 1 used to be a canonical
| way to `halt`
| mcguire wrote:
| I used to work with a long-time AIX kernel developer. His
| method of shutting off his machine was "sync; sync; kill
| -9 1".
|
| Of course, his method of preparing to move offices (a
| common occurrence at IBM) was to
|
| 1. Take his (RS-6000) workstation home with him the night
| of the move.
|
| 2. Otherwise, just lock his desk.
|
| He didn't have anything in his office but his chair,
| desk, and workstation.
| olddustytrail wrote:
| I'm pretty sure psdoom warns you against killing init
| LorenPechtel wrote:
| I had something of the opposite experience.
|
| Digging into the manuals I figured out how to launch the
| compiler as a background process so I could still have a
| working system while waiting for it. Brought the whole
| classroom to a halt.
|
| More digging revealed that the background priority was set well
| above user priority. AFIAK no malice involved, just someone who
| didn't know how to set the system up and left that landmine for
| me to find.
| havnagiggle wrote:
| A bunch of economists couldn't play nice?
| quickthrower2 wrote:
| Behaving like perfectly rational actors, of course.
| eru wrote:
| That's like complaining that real world physicists don't
| behave like frictionless spheres in a vacuum.
| dtech wrote:
| But they were, economic rational actors behave in their
| own self-interest
| jychang wrote:
| Getting his software stuck and then kicked off the
| computer is his self interest?
| Dylan16807 wrote:
| Wow, you annoyed someone enough to get your comment hidden,
| impressive.
| bstpierre wrote:
| In 1993 my freshman CS class was taught in scheme. All of our
| assignments had to be developed and tested on some shared
| Digital machine running Ultrix. The scheme interpreter was kind
| of slow to start, especially when there were 20+ users logged
| in. Helpfully, our TA taught us how to ctrl-z to suspend the
| interpreter, then edit our program in vi, and then "fg" to get
| back into the interpreter.
|
| Unfortunately the fg part of the equation was lost on about 2/3
| of our class... after editing they would start another scheme
| instance! I recall being in the terminal lab the night one of
| our first assignments was due, and the machine slowed to an
| absolute crawl. Can't remember exactly how it was resolved but
| I do recall being taught how to look for classmates running two
| or more instances of scheme to remind them about fg. (Also not
| helpful to machine load: "solutions" to the 8 queens problem
| with infinite recursion. The real lesson here was, in later
| years, to not be logged in on nights when CS 401 had
| assignments due.)
| gte525u wrote:
| I had a similar story with a friend in college in the 2000's.
| He would always hit Ctrl-z'd to "close" emacs when logged
| into the server which would've been fine if he wasn't using
| screen or tmux as well. At some point, he was using a
| ridiculous amount of RAM on the server and the admins
| suspended his login to force him to come in.
| grepfru_it wrote:
| Once upon a time, we had several Sun Enterprise 450s that my
| college used to teach Oracle to students. It was well
| underutilized and the hit game Quake had come out. Of course we,
| the IT support staff, ran a Quake server and invited all of our
| friends to play on it. Imagine our surprise when one of our
| professors we support came into our office and said "Hey our
| Oracle instance is very slow, can you guys take a look at it?".
| Whoops, we shutdown the quake server and he later sent an email
| "I don't know what magic you guys did, but the performance is
| amazing!".
|
| Another fun one, not targeted at professors, but at our student
| compute lab. We had a lab of 25 Sparc Ultra 60s that was pretty
| well utilized. Well one day, before I became a sysadmin, I was
| thinking to myself "all of these servers are rsh enabled, what if
| I logged into all of them". So I wrote a script that would cut up
| an AU file (sun's audio format) into tiny parts and then wrote a
| program that would synchronize with each other and play a
| different part out of a different workstation. I vividly remember
| playing a screaming sound in a ring around the entire room at a
| low volume before playing the entire sound out of the three
| middle workstations at full volume a few seconds later. The lab
| was full. At least 15 people immediately noped out. I was sitting
| in the back cracking up.
|
| Another time the sysadmins of the same computer lab left rwalld
| running. So I sent an rwall "The system will shutdown in 5
| minutes" or whatever the shutdown message was. The professor at
| the time got angry "they always do this, they perform maintenance
| whenever the g.d. please" and he stormed out of the room.
| Suddenly the professor and an angry IT administrator was peering
| in the door and pointing at me. They threatened to revoke all of
| my access which would cause me to fail out. I just shrugged, I
| knew what they were up against and instead asked to work for
| them. The anger turned to surprise and I worked there for almost
| 6 years before leaving for greener pastures.
|
| Ahh the SunOS days were really the days of yore
| lbriner wrote:
| Since I was at college in the second half of the 90s, we still
| had unix text consoles for reading emails so my favourite prank
| was to tell others in my dorm that I had worked out how to
| remotely log in from the dorm (we had to use a computer room back
| in them days!) and with my 10 line Turbo Pascal program created a
| fake login screen like looked identical to the normal one. After
| capturing a password, I would explain to each person that maybe
| it wasn't quite working so "sorry", so they were none the wiser
| that they had given me their passwords.
|
| I didn't do anything with the passwords, it was just interesting
| how easy it was to get away with.
| dspillett wrote:
| Someone was discovered to be collecting passwords that way on
| our universities VT terminals (I'm old enough that at Uni plain
| text terminals were still a thing, though they were generally
| used just as terminals for email & such when the lab rooms full
| of PCs were fully occupied) by leaving what looked like a login
| prompt on-screen. Someone with much tech knowledge immediately
| saw it wasn't quite right (that is how the issue was found) but
| these were terminals used by the general populace not just us
| CompSci students so the vast majority of the users were not at
| all technical (what we might assume almost everyone knows these
| days was still new fangled magic to the average student back
| then, for many arriving at Uni was their first encounter with
| having an email account for instance).
|
| To my knowledge they never worked out who did it, or how long
| it had been going on for other than "may have been months",
| because the fake login app would exit and logout after sending
| off the captured credential, and next time it was run it was
| done from one of the captured accounts, so only the very first
| capture would have been done by the culprit's own account (even
| that maybe not if they'd guessed or stolen a password by other
| means first). Captured credentials were sent to a popular high
| volume usenet newsgroup so they couldn't track who was reading
| the result that way. Also, no evidence of the attacker actually
| using the compromised credentials for anything else, so it was
| possibly someone "playing" to see what they could do rather
| than a more malicious intent.
|
| It became standard practise ("enforced" by notices in large all
| caps text) to reset terminals before logging in to be more sure
| that was a real login prompt.
| loph wrote:
| I once set up a job on a co-workers VAXstation 3100 that would
| run XCrab every 10 minutes. What is XCrab? It is an annoying
| little program, when it runs a crab scurries across the screen,
| grabs the mouse pointer, and runs off the screen with it. I
| renamed the job PRT$SYMBIOINT so it looked like part of the print
| spooler, he never figured it out.
| Ensorceled wrote:
| I installed that on a coworker's machine only to find out he had
| a bug phobia. He shrieked like a kindergartener! I had to buy him
| beers for weeks before he forgave me.
| fvdessen wrote:
| This story is either fake or exaggerated, the number of roaches
| in xroach is constant, and there's a hard limit as they are
| statically allocated (I checked the original source code)
| nuancebydefault wrote:
| I never heard before about roaches that can be minimized. Reminds
| me of the original meaning if debugging -- physically removing
| cockroaches.
|
| Probably the story would sound more funny to me if I knew more
| about xwindows and SPARCs?
| fcatalan wrote:
| Mid 90s were fun at Uni.
|
| Replacing a T-connector with a broken one to sabotage unpopular
| classes... Or binary searching it with a terminator to save one
| you liked...
|
| Learning that pinging Windows 3.1 with a big payload would BSOD
| it and writing a script to perform a rolling BSOD of the entire
| lab while sitting in the back...
|
| Sending random insults to random spots on ttys while people read
| their mail using Elm...
|
| Writing a trojan to steal and then delete the MUD accounts of the
| dudes hogging the only 2 computers with Internet access available
| to undergrads...
|
| And being caught and let go with a not so stern warning. Simpler
| times.
| phkahler wrote:
| >> Sending random insults to random spots on ttys while people
| read their mail using Elm...
|
| Receiving such a write and tracking down the offender for a
| face to face "you got a problem man!?!?" ;-)
| fcatalan wrote:
| I still treasure friendships forged that way :)
| Twirrim wrote:
| > Replacing a T-connector with a broken one to sabotage
| unpopular classes
|
| When I started working in academia they had _mostly_ phased out
| 10BASE2. Every now and then we 'd get reports of network being
| broken and would have to get out the break detector to track
| down where. Inevitably we'd find a student had unplugged a
| T-connector in a classroom, disrupting the others on the same
| loop.
| mcv wrote:
| I believe either my brother or someone he knew once wrote a
| program that spawned lots of child processes. He did that to test
| a scheduler or something like that, but it got a bit out of hand
| and swamped a major server in endless processes. Admins weren't
| pleased. But also not too upset, because they approved of
| students experimenting. We had pretty cool admins.
| danieldk wrote:
| A fork bomb. In shell: :(){ :|:& };:
| doetoe wrote:
| Could you explain how this works?
| system33- wrote:
| A function called ':' is defined. In its body, it calls
| itself twice at the same time (':|:') (piping the output of
| the first call into the second, which doesn't do anything
| useful) and sends these calls to the background ('&').
| After function ':' is finished being defined, it is called.
|
| The first call spawns two clones. Each of those spawn two
| more. Etc.
| doetoe wrote:
| Great, thanks!
| xav0989 wrote:
| :() defines a new function called : { :|:& } is the body of
| the function, where we call the : function recursively,
| piping (|) its output to another call to :, then
| backgrounding the whole thing (&) ; indicate the end of a
| statement and the start of a new one : and finally the last
| : calls the function we defined to start the chain
|
| Essentially each time the function is ran, it creates 2 new
| copies of itself, which each create 2 copies of themselves,
| etc. until your OS stops responding and crashes.
|
| Nowadays many shells recognize this particular fork bomb
| and refuse to execute it
| _flux wrote:
| > Nowadays many shells recognize this particular fork
| bomb and refuse to execute it
|
| Nice try!
|
| Though, do they really? I quickly checked if I would find
| something like this in bash, zsh or tcsh and failed, but
| I only spent a minute or so..
| sva_ wrote:
| Well I can experimentally confirm that it works on
| zsh/alacritty ;)
| [deleted]
| [deleted]
| mcguire wrote:
| Oh, lord. The sheer number of fork-bombs launched by the
| students in the systems programming course the week the
| professor introduced fork()....
| sam99x wrote:
| In the early '90s, I was a fresh Computer Science undergraduate
| student at a state university. Our computer lab was packed with
| the Sun SPARCstation IPCs, each running SunOS. We had this
| rudimentary email system that everyone in the department used to
| communicate. The tech-savvy folks, of course, had started
| exploring Usenet, but for the majority of us, the e-mail was our
| digital universe.
|
| One day, my group of friends and I decided to have some fun. We
| concocted an idea inspired by the famous 'fortune' command that
| prints out random adages. We wrote a simple shell script that
| would take a random line from a text file full of humorous and
| nonsensical messages we'd written, then mail it to a random user
| in the computer science department. The script was set up as a
| cron job, scheduled to send one of these messages every hour.
|
| Initially, it was just a harmless prank. People found the
| messages funny and would often share them in the lab. The source
| of these messages became the talk of the department, but nobody
| knew where they were coming from. We took great pleasure in
| watching our peers and professors speculating about the
| mysterious sender.
|
| However, things started to get out of hand when the Dean received
| an especially absurd message that read, "Why do computer
| scientists confuse Christmas and Halloween? Because Oct 31 == Dec
| 25!" He found the joke incomprehensible and thought it was some
| sort of cryptic message or even a potential threat.
|
| The campus IT team was called in to investigate, and a week-long
| frenzy ensued as they tried to trace the source of the emails. My
| friends and I watched in trepidation, wondering if we'd be found
| out and expelled for our seemingly harmless prank.
|
| Finally, after several sleepless nights, we decided to turn
| ourselves in. We went to the Dean and confessed. After an anxious
| silence, he started laughing. Apparently, he had been let in on
| the joke by one of the Computer Science professors and was
| waiting to see how long it would take for us to come forward. He
| was good-natured about the prank and found our initiative
| creative, although he warned us about the unintended consequences
| of such pranks.
|
| Looking back, it was a fun, memorable prank that gave us a
| valuable lesson about the ethics of technology use. It's a story
| I often recount when I'm teaching my own Computer Science
| students about the importance of ethical conduct in the digital
| world.
| unilynx wrote:
| The interesting part is that it occurred to no one to just reboot
| and see if that fixes it. Apparently systems were a lot stabler.
| kristopolous wrote:
| Calling IT is the right move here. Could have been an intruder
| or a remote user doing something important.
|
| It's a different relationship. The department workstations were
| much closer to the refrigerator or copy machine. If it's broken
| you don't touch it and just call somebody.
|
| In modern money these machines were between $7,000-$10,000 each
| depending on configuration.
|
| To put it in context, pretend you work somewhere where they
| provide you with a half height rack and a Precision 7960
| https://www.dell.com/en-us/shop/workstations-isv-certified/p...
|
| And it starts acting up. What do you do?
|
| (As an aside, I've always wondered how many maxed out
| configuration orders they get - you know, when you kick that
| price up to $100k - what's the threshold where they ask if they
| could put someone on a plane to visit you? 10 of them?)
| eru wrote:
| I'd probably reboot it every day (or every week) as a matter
| of course. Not just when there are problems.
|
| Just so that I know that there are no unexpected surprises
| happening when I need to reboot it in an emergency.
| aflag wrote:
| That sounds needlessly disruptive. It is a workstation
| after all. I restart mine as little as I'm allowed to and
| once a month sounds way too much already.
| dmbche wrote:
| What is the negative?
| aflag wrote:
| You have to close all windows (and possibly tabs in your
| editor), restart long running jobs you have in the
| background, restart your SSH sessions, lose your undo
| tree, lose all the variables you have loaded in your
| interpreter or bash, among others that I have possibly
| forgotten.
|
| All recoverable, but annoying. I can't imagine doing that
| every day. It's fine for a home computer, but for a
| workstation, I just want it always on. Though these days
| even my personal laptop is essentially always on.
| computerfriend wrote:
| Downtime.
| kristopolous wrote:
| At least on older hardware, number of reboots was a
| stronger correlative with failure than hours on.
|
| I'll readily admit this may have been apocryphal. It was
| a common adage when I was a child in the 80s and now that
| I'm actually qualified enough to suss out such a
| statement I've never cracked open the historical
| literature at archive.org on this one to actually check.
|
| It could just be a portage from incandescent lightbulbs
| (where this is true) and older cars (where this is also
| true). The idea of non-technicals thinking magical
| computer dust having the same problem is understandable
| pjc50 wrote:
| Somewhat against UNIX culture. There used to be proudness
| in having very high system uptimes. The modern security
| arms race has basically killed that.
| somat wrote:
| I don't think that long uptimes is unix culture at all.
| unix was always about being small, simple and fun to use,
| A place where having something now is much more valuable
| than being correct later. A hackers OS. This is also
| where most of the sins of unix come from.
|
| "We went to lunch afterward, and I remarked to Dennis
| that easily half the code I was writing in Multics was
| error recovery code. He said, "We left all that stuff
| out. If there's an error, we have this routine called
| panic(), and when it is called, the machine crashes, and
| you holler down the hall, 'Hey, reboot it.'"
|
| https://multicians.org/unix.html
| AnimalMuppet wrote:
| Not sure it's just security. I wonder if it's also that
| people don't host important services on non-redundant
| machines as much anymore.
| TristanBall wrote:
| I'd guess orders for these probably skew to the higher end.
|
| If you're putting workstations in racks it's either to share
| them, or due for power/cooling/noise reasons, and the fact
| that you've got a workload that justifies having those kind
| of problems probably means all your other costs will still
| dwarf hardware.
|
| There's usually a large premium on whatever the current
| largest size dimms, ssds and the top 10% or so of cpus and
| video cards. So I expect they sell a lot of machines that are
| "50%" size ( either max physical capacity with 50% size
| components, or half physical capacity, with 90-100%
| components ), and a fair number of maxed out just because it
| will often be cheaper to have 1 maxed out option then 3
| smaller ones, and budgets don't matter except they do.
|
| Places who cost engineering time at $100k/hour won't blink at
| $100k computers if it gets the job done.
| tmn007 wrote:
| Hard reboot on those old Sun systems usually meant a dirty
| filesystem and telling off by the admin as they needed an fsck
| IggleSniggle wrote:
| No matter how many times I see it I always read fsck as
| "(for) fucks sake" and then internally correct to "file
| system check." I think I've got a flashbulb stressful memory
| floating around in there.
| r_klancer wrote:
| The headline put me in mind of a different memory I had of the
| campus BBS from undergraduate days, and then I clicked through
| and realized that the author was actually the admin of that BBS!
|
| Anyway, in addition to the BBS there was also an IBM mainframe
| (?) running VM/SP that you could connect to, and somehow that was
| how you got to IRC.
|
| One night several of us spent hours chatting on IRC, and the next
| day we got called into the campus computing service where it was
| patiently explained that some professor's overnight batch job
| running stats had failed because it was constantly being
| interrupted by interactive-priority jobs ... i.e., our chat
| sessions. Which we should now stop.
|
| I remember writing a passionate open letter using my vague
| knowledge that had trickled out about "hacker culture" in places
| like Berkeley where students were surely right now exploring
| these new things called "Usenet" and "the Internet", arguing that
| even though _we_ weren 't doing anything fancy like running stats
| for an economics paper, and even though we didn't know what any
| of it would actually amount to, the important thing for our
| education was that we had the chance to experiment with it for
| ourselves...
| bigjump wrote:
| The simple pranks are the best.
|
| We just used to add an alias for 'ls' which introduced a subtle,
| but ever increasing delay each time it was run.
| _flux wrote:
| Debian also comes with the package 'sl' that can be amusing. At
| first at least.
| raverbashing wrote:
| Is it too late to open a bug with the xroach developers?
| oaiey wrote:
| while (fork()) { while (malloc(1000)) { }
| } while (true) {} // or whatever true was in good old C
| ;)
|
| my most loved program when I was a young student on a mainframe
| with 20 other kids.
| boffinAudio wrote:
| We used to 'rain-bomb' each others terminals:
|
| $ rain | wall
|
| This was always really fun with the newcomers to the ops centers
| ..
| notbeuller wrote:
| Our unix (Gould GLX or something?) with dozens of terminals
| lacked appropriate permissions on /dev/ttyNN - so we just piped
| rain directly to the neighbors terminal.
| nickdothutton wrote:
| In my day we ran irc servers and MUDs on the professors
| workstations, which were of course tied in to the campus-wide
| NIS/NIS+ system, and often more lightly loaded than the big iron
| (that being VAX6000 or 8000, or if you were lucky a Sparc20).
| poutine wrote:
| Back in the day I played a prank on a fellow sysadmin by adding
| an 'echo "sleep 1" >> .login'
|
| Took him a week to figure it out, he was not pleased. :)
| deckar01 wrote:
| I once had to troubleshoot the math department director's PC
| misbehaving. It turned out that he let prime95 have every spare
| cycle on a core 2 duo for a decade and the machine would only
| boot if it had cooled to room temperature.
| Exmoor wrote:
| It took me way too long to remember that Prime95 is useful for
| something other than stress testing.
| oxygen_crisis wrote:
| Looks like the project averaged about one new Mersenne Prime
| per year for 1996-2009, and then only 4 hits for 2010-2018
| with none since 2018.
|
| Obviously the tflops::hit difficulty ratio is ramping up as
| the numbers get larger, but I can't help wondering if the
| cryptocurrency craze dampened their work rate.
|
| They're reporting 78,012 tflops of work done today, but my
| five minutes of investigation wasn't enough to find a
| historical chart of tflops/day and five minutes is about the
| limit of my curiosity on this matter for now.
| jl6 wrote:
| When the project started, CPU frequency scaling wasn't a
| thing, so CPUs would run at full speed (and full power
| draw) 100% of the time. If you weren't making maximal use
| of the CPU, any remaining capacity would go to waste.
| Distributed computing projects could make use of that
| remaining capacity.
|
| Today, CPUs are built with power efficiency in mind, and
| will attempt to scale down rapidly when not fully in use.
| Thus there is no longer such a thing as "spare CPU time".
| Any time spent on distributed computing projects is paid
| for in electricity costs. Some choose to continue anyway,
| but many have been disincentivized.
| organsnyder wrote:
| For a while I had a Home Assistant automation that would
| spin up Prime95 on a machine in my homelab when the
| closet it was in (in an unheated garage) got too cold.
| The closet also has the water meter, so it has to be kept
| above freezing. There's also a resistive heater, but I
| figured I'd rather get a bit of productive use out of
| those watts.
|
| Then I realized that the computers heated the closet
| plenty without artificially pegging CPUs, so I didn't
| bother reimplementing it when I did a migration.
| tedunangst wrote:
| The hlt instruction has been around for a while.
| post-it wrote:
| I don't think that saved any power on a CPU without
| frequency scaling.
| spookthesunset wrote:
| Hmmm.... there was some windows program called
| "waterfall" that kept your CPU cool when it was idle.
| Very useful for overclockers.
| ChainOfFools wrote:
| It may have been replaced by a cryptocurrency indeed, for
| there was PrimeCoin, one of the very few that actually did
| something that was both productive and unprofitable
| (critically important for the economics of mining) with its
| mining cycles, and that is look for prime numbers. Although
| I don't remember if these were Mersenne Primes. It was one
| of the very earliest altcoins and by its nature was CPU
| bound which made it unpopular with large scale mining
| farms, but extremely popular with CPU cycle thieves working
| in clueless corporate and educational IT departments.
| JTbane wrote:
| Unused cycles are wasted cycles. /s
| ufo wrote:
| Does anyone know where we find a video of xroach in action?
| mcguire wrote:
| Once upon a time a (fameous) CS professor reported that his email
| was annoyingly slow.
|
| He was using the good ol' mailx MUA.
|
| He never deleted emails.
|
| He never moved emails out of his inbox.
|
| He had been doing this for many years.
|
| His .mbox file was many, many megabytes.
|
| Apparently, he had never noticed the problem before because he
| very rarely logged out, but IIRC some system work meant he needed
| to do so several times just prior to his complaint.
| lizknope wrote:
| I was in college in the mid 1990's. Our school had hundreds of
| Unix workstations from Sun, HP, DEC, IBM, and SGI. Everything was
| tied together with MIT's Project Athena which used the AFS Andrew
| File System, Kerberos, and the Zephyr instant messaging system.
|
| Your home dir would be mounted as /school/login
|
| The directory paths would be really long like
| /afs/school/math/maple/maple5.3 so there were 2 commands named
| add and attach to mount dirs to /school
|
| add maple5.3 and you would have /school/maple5.3 and it would
| source .environment script in that dir to set up the tool and it
| /school/maple5.3/bin to your PATH
|
| The attach command did the same thing but did NOT source the
| .environment file
|
| If you needed to access another student's dir it was explicitly
| written in the intro computing class book to use attach and not
| add
|
| I had a lot of scripts and utilities that friends would use. They
| told other random people that I didn't know.
|
| So of course I made a file that would be updated any time I
| logged in showing my current machine name. Then I made a
| .environment file that would xhost + my_machine and send me a
| Zephyr message saying "I just added and xhosted your machine"
|
| I would wait a few minutes and then run xflip and xmeltdown and
| set the -display to their machine. If they were in the same
| computer lab as me I would see them start to freak out. These
| programs basically froze your display for a few seconds while
| inverting the screen or causing everything to appear to melt to
| the bottom.
|
| https://github.com/veltzer/xmeltdown
|
| No real harm but it was pretty funny when I was 19
| zerealshadowban wrote:
| for OS class we had to write a distributed game on top of the
| Andrew File System; debugging a nasty crash I managed to
| distill our team's code down to 10 lines to remotely
| crash/reboot any chosen AFS workstation on campus; thus I
| regularly emptied workstation rooms at CMU (most students just
| gave up after a couple of sudden computer reboots) so that CS
| friends could work on and finish their homework; I may have
| also crashed some professor workstations from time to time, idk
| lizknope wrote:
| I still miss AFS ACLs.
|
| For the last 25 years at 8 different jobs everything is over
| NFS. Every company uses Unix groups and some have used groups
| to manage project access. Sometimes it can take 3 days to get
| added to a group.
|
| When I started college in 1993 we learned in the "Intro to
| Computing Environment" class our first semester how to create
| ACL groups.
|
| I have a degree in computer engineering so I understand
| binary, octal, hexadecimal, but chmod 755 or 644 or whatever
| is not exactly intuitive.
|
| AFS permissions are much easier to understand. When we had a
| group project we would all make a directory for that project
| and only give access to the other people in our group. We
| could give them read or write and everything worked great.
|
| I know NFSv4 has ACL support but I've never seen it actually
| used anywhere.
| nirui wrote:
| > Please be aware that this version still has some bugs
|
| That's ... very obvious, but thanks for the reminder.
| RegnisGnaw wrote:
| In unversity, I was bored one day and added this to another
| student's .bashrc echo "sleep 1" >> ~/.bashrc
|
| He used the Solaris SPARC machines to do his work, so everytime
| it logged in it opened 4 terminals or so (not sure why). By the
| time he asked the help desk for help, it was up to a 6 minute
| wait after logging in before he got the prompt.
| once_inc wrote:
| Once when doing tech support at a local hospital, one of the
| nurses called us stating that she had "some sort of weather
| report" up in a window on screen, but she couldn't click it away
| because the most would go under the screen. Obviously piquing my
| interest, I told her not to touch the computer until I arrived.
|
| Since the hospital was quite big, it took me about 10 minutes to
| reach her workstation, where she exclaimed that "the window
| closed on its own a minute ago. I swear it was on there for half
| an hour".
|
| That, coupled with the layout of the desk, the description of the
| window led me to a hypothesis. I pressed the button on the
| monitor (which she had unknowingly pressed with the corner of her
| keyboard) which called up the system menu of the display. It
| showed 100% sun (brightness). The mouse would go under it.
|
| Then, I hiked back another 10 minutes to await the next phone
| call.
| nuancebydefault wrote:
| Nice story! Sounds like the more advanced version of the "my
| 4x-labeled cupholder is broken" story of the nineties.
|
| In fact the nurse gave a quite accurate description of events i
| might add.
| c22 wrote:
| I had to do a tech support call once where 'the screen keeps
| glitching out I think I have a virus' ( _The Net_ was still in
| theaters). I showed up, removed the boombox with two large
| speakers from on top of the CRT and like magic the problem was
| solved!
| nyanpasu64 wrote:
| I have the misfortune of my rescued VGA CRT displaying
| incorrect colors in the corners, unless I either leave
| magnets on the screen, or flip the magnets while degaussing
| and remove them before using the display.
| tomcam wrote:
| Well now I need to know what you can use a VGA for these
| days
| arcanemachiner wrote:
| 640x480, but that's not important right now.
| gtk40 wrote:
| Works great in old conference rooms... I have a USB-C VGA
| adapter in my bag still.
| [deleted]
| mulmen wrote:
| I also did tech support in a hospital. I'm not sure IT is a
| value add in that environment, at least not as much as IT
| thinks it is. Nurses are busy doing things like saving lives
| and caring for people experiencing the worst day of their life.
| On top of that nurses have to deal with poorly implemented and
| maintained workstations. Then when they ask for help the very
| people who created the problem in the first place come and
| belittle them.
|
| I'm not accusing you of anything. Just noting my own perception
| that IT people tend to be very smug and see the world from an
| IT-centric perspective. Nurses aren't dumb and they certainly
| aren't lazy. They just have better things to do with their time
| than deal with inconsequential IT issues.
|
| As I recall everything in the hospital that was actually
| critical to providing care had some specialist that maintained
| the system. The computer running the MRI machine wasn't bound
| to Active Directory and might not even be on the network.
| Issues with it were routed to GE, not the guy that fixes
| printers.
| tiffanyg wrote:
| Ha - I know where you're coming from, but, like every
| opinionated SOB on this site, can't help but throw in my own
| opinion*:
|
| 1) The parent comment seems completely neutral and non-
| judgmental. Seems quite just "I had this experience",
| essentially a set of facts (compared to frequent enough
| comments that possibly really ought to generate a response /
| "note of approbation").
|
| 2) Stereotypes are the epitome of judgmental thinking,
| language, attitudes, etc. That may sound judgmental itself,
| and I apologize for that - that's due, in part, to
| connotation "issues" with words we use (although, I can't,
| obviously, claim that even removing those removes all of that
| issue - I am literally labeling and characterizing strictly
| in denotation). To be fair, people, in general, can be very
| smug.
|
| In my experience, there has been an "enrichment" of that in
| "IT", but, for example, try talking to some of the especially
| high-ranking surgeons, say ... or, certain professors. In
| particular, I've personally come across a somewhat bimodal
| distribution, I think. Some people who reach "very high
| levels of expertise" are very humble ("right-sized" - not
| subservient or etc.) and super nice (surprisingly willing to
| help and talk to even "the layman" / "novice"). Then, there
| are the outright "arrogant bastards".
|
| So, to add some kind of summation - calling out "IT people"
| specifically, and especially the parent comment ... well,
| what's the point? Again - not meant to be rhetorical or
| aggressive ... but, I think many would agree that people in
| general should cut that $h1t out.
|
| _This opinion brought to you by my "Big Giant Head...
| remember, when you're thinking of giant heads, think [my] Big
| Giant Head..."_**
|
| * Which, we all know is likely to be comparable to ...
| something else everyone's got. Though, I'm telling myself, of
| course, that I've got something useful to say. "Caveat
| lector". :)
|
| ** With apologies to the writers and other people involved in
| making "3rd Rock from the Sun"
| rat9988 wrote:
| You are way too apologetic with the original post. It was
| not just a set of facts. You could feel the superior
| attitude. It's kind of obvious in the last sentence. The
| person you answer did well to call it out.
| richie_adler wrote:
| I read the post in Mastodon with a tone of amused
| incredulity at the unusual situation. Yes, some unusual
| habits of the professor may have contributed, but I don't
| read any negative judgement there.
|
| Somebody got burned too many times with IT people, I
| think.
| [deleted]
| ShakataGaNai wrote:
| Every group of people who's remotely decently specialized...
| will get very smug assholes. I've met IT people who just want
| to help you get your shit done, and those who look down at
| you for being a "stupid user". Also I've met Doctors whom
| think they are god, and Doctor's who want to be a partner in
| your health journey and are totally non-judgemental (at least
| outwardly).
|
| I'm sure you'd find the same in any similar field. Engineers.
| Pilots. Mechanics. Nurses.
|
| And yes, everyone looks at the world from their personally
| centric view of the world. It's the only way we, as humans,
| know how. After all, how would you get to your oh-so-
| important job if not for the road engineer, or the mechanic
| who built your car, or the city designer who designed the
| routes that you use every day.
|
| Some are more aware of main character syndrome [1] than
| others... and some are just less assholes than others.
|
| [1] https://www.cxomedia.id/human-
| stories/20220722170529-74-1756...
| [deleted]
| nuancebydefault wrote:
| Thanks for sharing the interesting article!
| teh_klev wrote:
| Seeing as we're sharing our fun and games...
|
| When I was at college back in the 80's we had access as students
| to the college's VAX 11/750 (an 8750 Systime clone) to work on
| our coding projects. The student terminals were on one half of a
| large divided room, the other half being used by the college IT
| folks. Often, if there wasn't a spare terminal on the IT admin
| half of the room, one or two of the IT folks would use two of the
| nearest terminals just over the divider.
|
| One day, bored out of my mind waiting for my COBOL project to
| compile, I wondered if I could capture the sys admin's username
| and password. I wrote a script using the CLI to perfectly
| simulate the login prompt complete with beeps, messages and all.
| All it did was clear the screen, sit there waiting for user to
| enter their username and password, when they did the script would
| mail me said username and password, display a username/password
| error then logout to the real login process.
|
| After trying the script out on a couple of unsuspecting
| classmates and having a bit of anonymous tomfoolery I decided it
| was time to try this out for real with the sysadmins. I logged
| into both terminals the IT folks normally used and left the
| script running. A few hours later I returned and to my surprise
| and mild anxiety I found out that I'd captured the SYSTEM login
| password :o. For about a month or so I'd full control of that
| machine, and would re-run the script occasionally whenever the
| SYSTEM password changed. I told no-one and on my last day at
| college logged in and deleted the script, just in case (this was
| around the time the law in the UK was getting a bit heavy with
| regards to unauthorised computer access).
|
| Combined with access to the huge set of manuals for that machine
| I spent a heap of time exploring and learning about VMS and no-
| one had a clue.
| samch wrote:
| Fun fact: Login spoofing like this is why, from Windows NT on,
| users have had to first enter a security context with
| Ctrl+Alt+Del.
|
| https://en.wikipedia.org/wiki/Control-Alt-Delete
| gumby wrote:
| an approach that goes back the the rainbow books, at least.
| There was some scheme to use the "break" key on the teletype
| for this (maybe in Multics, or OS/360 perhaps?) but I have no
| idea if it was ever implemented.
|
| For those who don't remember, "break" was not an ASCII
| character but a literal long unmaskable pause in
| transmission, and couldn't be generated in software or by
| reading the paper tape punch, nor could it be read on the
| host side into an input buffer as it wasn't a character.
| eichin wrote:
| The magic words being "Secure Attention Key" (on multics in
| particular, it was specifically caught by the Front End
| Processor, so nothing in the OS could interfere by (for
| example) catching the signal and printing a fake login
| prompt, becauase it was literally a separate computer
| handling the request...)
| TimTheTinker wrote:
| In MS-DOS, Ctrl+Break could be simulated through ASCII
| character 0x03. Literally, hit Alt+3 and it would respond
| the same way.
|
| The sysadmin for my high school computer lab had written a
| text-mode DOS login screen that would start Windows 3.11
| for workgroups after the user logged in. A few of us kids
| figured out we could just Ctrl+Break out of it and
| install/play DOOM, Descent 2, etc. He wised up and wrote a
| trap for the Ctrl+Break sequence, but I discovered the
| Alt+3 trick and we continued on our merry way. I don't
| think he ever figured out how we did it.
|
| (We also hid our games inside a directory named Alt+255,
| which appeared as a space. A single space was not allowed
| as a directory name, so it felt like magic to us.)
| chx wrote:
| Ha yes, name your TSR keylogger REMalt+255.COM , put it
| into AUTOEXEC.BAT , it looks like an innocent comment.
| 0x6c6f6c wrote:
| This is great. Reminds me of the BASIC program I wrote on my
| Ti-83 to simulate the memory reset process for algebra tests
| because our teacher walked around and would run it himself.
|
| Big surprise now I program for a living.
| teh_klev wrote:
| > Big surprise now I program for a living.
|
| Oddly, me too :)
| gonzus wrote:
| This seems like a rite of passage... I did the same thing with
| the VAX at my school, but decided to come clean and gave the
| sysadmin all the passwords I gathered after one day (including
| several with SYSTEM privileges). They gave me my first job :-).
| I also made sure to grant the necessary permissions to one or
| two obscure accounts, so that I could regain SYSTEM when it was
| revoked on my "official" accounts. Fun times, and innocent too
| -- I never used the privileges to cause havoc.
| intrasight wrote:
| I recall a student at CMU getting in big trouble for doing that
| - around 1985.
| dormento wrote:
| Its funny how writing a user login replacement seems kind of
| ubiquitous for all future hackers. Mine was in Visual Basic (5
| iirc) for a Windows (Novell?) network. This was back in school.
| You could trivially change win.ini to set it up to run _before_
| the real login screen. Mine would save the username and
| password to either a shared network drive or a local file, then
| display a "password error" and exit to the real login prompt.
|
| What got me in the end was that a "friend" used the same trick
| and started copying peoples files from their network account to
| his own. My suspicion is that when he eventually maxed his
| quota, the system must've warned the network admin... a cursory
| look would later reveal he copied some teacher's thesis files,
| and that was a big no no.
|
| Eventually this incident would land me my first computer
| related job as a junior tech support/network admin.
| db48x wrote:
| Stories about software bugs are the best :D
| rwmj wrote:
| Back in the day we banned using animated xlock to lock your
| screen. The Sun workstations in the lab ran the X server local
| and picked a random other machine to run the window manager and
| clients when you logged in. (Which is kind of an odd way to do it
| when I think about it now, but also cool that it was possible.)
| However this was all running over shared 10 Mbps ethernet with
| probably 100 machines and only 2 or 3 segments. This all worked
| fine until a few people use animated xlock running remotely over
| the shared network.
| dspillett wrote:
| _> ran the X server local and picked a random other machine to
| run the window manager and clients_
|
| Are you sure they were full workstations and not more dumb
| terminals (just enough processing power to be an X display)
| with all your logins being to a central beefy server (or one of
| a few) rather than some random machine?
|
| If that were the case then an animated xlock would potentially
| chew up an unfair amount of CPU time as well as clogging the
| network spitting the results out to your local X display.
| rwmj wrote:
| Some were indeed "dumb" X terminals, but most were top of the
| line Sun workstations provided at greatly reduced cost to the
| university.
|
| The best machines were the few HP PA-RISC ones though.
| Blazing fast.
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