[HN Gopher] iOS 14 and Facebook Pixel causing increase in PSL in...
       ___________________________________________________________________
        
       iOS 14 and Facebook Pixel causing increase in PSL inclusion
       requests
        
       Author : CameronBanga
       Score  : 210 points
       Date   : 2021-04-07 15:54 UTC (7 hours ago)
        
 (HTM) web link (github.com)
 (TXT) w3m dump (github.com)
        
       | lmb wrote:
       | Seems like the right move from a volunteer run project, what will
       | the future will hold though? Artificial scarcity is always a
       | problem.
       | 
       | On another note, for just 20k$ I can offer you exclusive use of
       | the xxgfzrf.dinglebop.me Public Suffix so that you can keep
       | tracking your users. Please reach out to sales@example.com if you
       | are interested.
        
         | devrand wrote:
         | To make things worse, it's basically impossible to remove a
         | domain from the PSL as no one knows how software built against
         | the PSL would handle it. A removal could break tremendous
         | amount of software that people rely on.
        
         | dialtone wrote:
         | It's interesting because being added to the PSL reduces your
         | ability to track users. So yeah, I have a bridge to sell you,
         | interested?
        
           | djrogers wrote:
           | > being added to the PSL reduces your ability to track users
           | 
           | Not really, in fact it can increase your ability to track
           | users if it's (ab)used in specific ways - see use case #2 and
           | #3 here:
           | 
           | https://github.com/privacycg/private-click-
           | measurement/issue...
        
             | dialtone wrote:
             | There's an approval process to be added to the PSL so
             | abuses would be quite surprising and easy to remove when
             | discovered.
        
               | iudqnolq wrote:
               | This entire discussion is literally about how that's not
               | the case.
        
       | irrational wrote:
       | >PSL is maintained by volunteers and there should be zero
       | expectation of turnaround times on PR (and a respect for the
       | labor burden shifted onto them by orgs using PSL as a bozofilter)
       | 
       | What is to stop Facebook from assigning an engineering team to
       | act as volunteers so the turnaround time drops to zero?
        
         | seoaeu wrote:
         | Um, because those engineers don't have commit access to the
         | repository? You can't just hire an engineering team and take
         | over any open source project you want.
        
           | irrational wrote:
           | Oh, I was assuming the engineering team would lie a pretend
           | like they did not work for Facebook. I assumed they would
           | slowly work to gain the confidence of those in control and
           | little by little they gain the access they required
           | themselves. Maybe they could pretend not to know each other
           | and use that to their advantage. Surely a company with the
           | resources of Facebook could manufacture fake alternate lives
           | for the engineering team to make them look completely
           | legitimate and harmless.
        
       | kogir wrote:
       | Isn't the easiest solution here for companies to register their
       | own domain? Why be company.service.tld and not just company.tld?
       | What are these businesses doing for email?
        
         | mrweasel wrote:
         | In this case I think the issue is trackers. If you owned a
         | retargeting or tracking service, you might have
         | customer1.retargetting.com and customer2.retargetting.com.
         | Apple will now see these as being the same site, unless
         | individually registered in PSL. This limits the amount of data
         | that can be aggregated by retargetting.com, unless each
         | subdomain is added to PSL.
        
         | donmcronald wrote:
         | Yes, it is. The main reason I can think of for using subdomains
         | would be for super low value content that isn't worth $10-30 /
         | year for a real domain.
         | 
         | There could also be a setup / maintenance angle I guess.
         | Specifying a big list of custom domains is more work than
         | *.example.com.
        
           | mangosquash wrote:
           | I work on digital advertising for a franchise where each
           | individual store manages their own shopify site at
           | location.franchise.com. Soon, these sites won't be able to
           | run ads that track purchases, unless franchise.com is added
           | to this list.
           | 
           | I understand the PSL managers' position that this is an
           | unfair burden to place on them though.
        
             | local_dev wrote:
             | >these sites won't be able to run ads that track purchases
             | 
             | Isn't that part of the purpose of the changes that Apple is
             | making? As a user, this seems like a great change. Less
             | tracking is a positive.
        
               | fshbbdssbbgdd wrote:
               | In principle, you can know that an ad click resulted in a
               | purchase without knowing who clicked the ad and who made
               | the purchase. Apple supports these kinds of measurements
               | for its own Apple Search Ads product.
               | 
               | The "entropy limit" you see people talking about
               | elsewhere in the thread is one means that attempts to
               | allow ads to be measured like this without revealing
               | information about the users. But if every store
               | *.shopify.com is in the same entropy pool, there won't
               | even be enough information to tell which ad campaign led
               | to a sale on which store.
        
               | mangosquash wrote:
               | Apple is doing some cool things to make personally
               | identifiable tracking from Facebook ads much less
               | pervasive, while still providing advertisers/businesses
               | data about whether or not their ads are working. These
               | things include sending batches of data every 36-48 hours
               | instead of data as it happens, etc. But in order for
               | these tools to work, Apple is asking Facebook to rely on
               | this list to see if subdomains would be able to set up
               | conversion events to collect this anonymized batched
               | data.
               | 
               | This system will make ads worse, but I think it's an
               | alright balance. Not being able to have any conversion
               | tracking will make ads dismal.
               | 
               | I wish that Apple would work to maintain their own list
               | that served this purpose, or provided support to the
               | volunteers that were tasked with keeping this updated.
        
               | donmcronald wrote:
               | Yeah, but if they're talking about physical location
               | franchises individually owned by local residents (there
               | are a lot), the tracking they want to do probably isn't
               | nearly as pervasive as Facebook as a whole.
               | 
               | For example, each location might want to track the
               | effectiveness of ads for their locality. Facebook is
               | probably a decent place for them to run ads too.
               | 
               | The big problem is that Facebook has earned a reputation
               | of abusing all the data they collect, so most people are
               | going to say the same thing as you and not have any
               | sympathy, but it probably screws over the poster you're
               | replying to pretty bad.
        
             | donmcronald wrote:
             | Yeah, I didn't quite understand it correctly at first.
             | That's a really good example of a legit use case that's
             | collateral damage from Apple vs Facebook.
             | 
             | I can think of other issues now too. For example, I think
             | government services should be structured as subdomains
             | instead of each department registering a separate domain.
             | This will encourage the use of separate domains if they
             | need to track effectiveness and that's bad IMO. We don't
             | want to normalize stuff like irsonline.com because of the
             | boost it gives phishing.
             | 
             | There's definitely two sides to this one.
        
       | jefftk wrote:
       | Summary: Apple introduced PCM [1], and to keep people from using
       | it for cross-site tracking it limits the bits available to a
       | single site (as defined by the PSL). If shop-a.retail.example and
       | shop-b.retail.example are completely separate, and don't want to
       | compete for bits, Apple will still treat them as a single site
       | unless retail.example is on the PSL. Being on the PSL is a big
       | change (partitioned cookies, etc) but could be appropriate for
       | different shops.
       | 
       | FB issued guidance suggesting domains like retail.example
       | consider getting themselves added to the PSL, and now the PSL (a
       | volunteer project) is getting a lot of requests. The PSL project
       | has put these requests on hold, and asked FB and Apple to work
       | this out. FB is talking to Apple in
       | https://github.com/privacycg/private-click-measurement/issue...
       | 
       | [1] https://webkit.org/blog/11529/introducing-private-click-
       | meas...
        
         | devrand wrote:
         | It sounds like there's two cases:
         | 
         | 1. Multi-tenant domains that probably should've always been in
         | the PSL (ex. to provide cookie silos) but are only realizing
         | now that they should be in it due to the arrival of PCM.
         | 
         | 2. Sites that want to abuse an eTLD to do something like give
         | all users on their social network a custom subdomain so that
         | they're not polluting the same pool.
         | 
         | --
         | 
         | I think it was actually reasonable for Apple to consider the
         | PSL as it's basically the most comprehensive eTLD list that we
         | have and would allow them to match browser behavior.
         | 
         | The problem now is that case (1) is sending a bunch of requests
         | at once as something will now actually break for these sites.
         | Before now it was really just them being lax with security and
         | not considering that cookies should be siloed. This isn't a
         | unique situation btw, PSL also saw a large increase in
         | inclusion requests when LetsEncrypt added rate limits based on
         | eTLDs.
         | 
         | (2) is obviously bad and there's really no other justification
         | for these sites being in the PSL.
         | 
         | Therefore I think it's reasonable for PSL to deny inclusion
         | requests that are solely for PCM reasons.
         | 
         | This all being said, the PSL is a massive hack [1] and really
         | needs to be replaced by something else. It probably is about
         | time for these companies to invest in a replacement.
         | 
         | [1]: https://github.com/sleevi/psl-problems
        
           | TechBro8615 wrote:
           | Nice link to the GitHub issue which explains the problems
           | clearly.
           | 
           | Can anyone explain why something like this wasn't implemented
           | in the first place via DNS TXT records or tied to SSL
           | somehow?
        
             | [deleted]
        
         | ghughes wrote:
         | That thread between FB & Apple is fascinating. The potential
         | solutions being discussed have significant implications:
         | 
         | 1. Apple: "not support eTLDs in PCM and only support TLDs" - so
         | no more ad attribution for multi-tenant domains.
         | 
         | 2. Facebook: "some sort of vetting process to determine who is
         | using subdomains in a way that is aligned with the intended
         | purpose of the PSL" - so Apple takes over the PSL inclusion
         | process and institutes strict vetting to prevent abuse of PCM,
         | which would presumably take months to implement.
         | 
         | This looks like a serious design problem with no solution that
         | could be implemented before ATT drops.
        
           | donmcronald wrote:
           | The biggest problem is that no matter what "scale" of
           | tracking is tolerable on a single domain / subdomain,
           | Facebook still gets the aggregate.
           | 
           | So if you fix it for small multi-tenant domains, nothing
           | changes for Facebook and they still get all the aggregate
           | data, right?
           | 
           | There's going to be a lot of collateral damage before ads and
           | tracking get fixed IMO.
        
           | cma wrote:
           | ATT?
        
             | Zelphyr wrote:
             | App Tracking Transparency
        
             | tony101 wrote:
             | https://developer.apple.com/documentation/apptrackingtransp
             | a...
        
       | nsxwolf wrote:
       | Paid Sick Leave?
        
         | kapp_in_life wrote:
         | Public Suffix List. It's in the link.
        
         | foolproofplan wrote:
         | Pumpkin Spice Latte
        
       | fotta wrote:
       | > It is inappropriate for presence or absense in PSL to be used
       | by Facebook as a means to include or reject entries due to the
       | IOS14 change, as PSL is not any form of security screen
       | whatsoever, and the volunteer team maintaining the PSL is
       | receiving the burden of being a sieve for the changes on
       | interaction between those systems, which is taxing our resources.
       | 
       | > The ONLY validation performed by PSL volunteers and Github
       | process to add listing in the PSL is to check that a DNS entry is
       | added by the domain administrator that can be tied to, and this
       | can be completely illusory and lite in reality in contrast to
       | perhaps the deisred level of security that had been intended
       | between Facebook Pixel and Apple.
       | 
       | > We are freezing the approval of new submissions that cite the
       | FB / IOS 14 interop issue in order to provide Facebook or Apple,
       | with a much more robust set of resources, the opportunity to sort
       | this out amongst/betwixt themselves.
       | 
       | https://github.com/publicsuffix/list/issues/1245#issuecommen...
       | 
       | ~~Seems like FB was abusing the work of volunteers here as a
       | reaction to changes in iOS 14.~~ I don't see why they can't run
       | their own PSL a la NTP servers.
       | 
       | edit: Seems like Apple was the one to declare PSL as canonical.
        
         | marketingtech wrote:
         | Apple is the company that declared this the canonical Public
         | Suffix List. Facebook is just directing their customers towards
         | it. "If you need to be considered a public suffix for Apple's
         | new policy, you'll need to send your pull request to this
         | repo."
        
           | HappyTypist wrote:
           | Apple should be officially supporting this project and turn
           | it into an independent, but full-time gig. If the maintainers
           | decline, Apple should hire someone to manage their own.
        
           | fotta wrote:
           | Ah I just read the links in jefftk's comment and it seems
           | like you're right.
        
         | tialaramex wrote:
         | The existence of multiple independent definitions for eTLD+1
         | would be very likely to create security holes, via a Confused
         | Deputy-type scenario.
         | 
         | If I was a security researcher, or a blackhat, and I found that
         | bar.example is on the Mozilla PSL, and so Firefox considers
         | foo.bar.example and quux.bar.example to be separate sites -
         | while it isn't on the Apple PSL and so Apple's APIs treat
         | foo.bar.example and quux.bar.example as parts of the same site
         | (or vice versa), then I know I'm going to find weird bugs where
         | Apple and the Firefox browser understand things about these two
         | names differently and I can likely exploit that.
         | 
         | The preference from PSL team members is to do _less_ with this
         | hack over time, to put it behind us. But alas instead it
         | motivates people to turn a hand-wavy notion  "You know, a web
         | site" into further reliance on the PSL instead of actually
         | building a robust solution to their problem.
         | 
         | This is particularly inexcusable from Apple because it's not
         | like Apple is hurting for resources. If they actually wanted to
         | solve problems, they could put the work in; so I think we can
         | conclude they weren't much interested in solving the problem,
         | only as usual in ensuring somebody else takes the blame.
        
         | NovemberWhiskey wrote:
         | > _edit: Seems like Apple was the one to declare PSL as
         | canonical._
         | 
         | Dependency on the Public Suffix List is already baked into
         | essentially 100% of the global browser market for purposes like
         | control of setting cookies - I'm not sure Apple made it any
         | more 'canonical' by depending on it here.
        
       | rectang wrote:
       | PSL: Public Suffix List
       | 
       | https://publicsuffix.org/
       | 
       | > _A "public suffix" is one under which Internet users can (or
       | historically could) directly register names. Some examples of
       | public suffixes are .com, .co.uk and pvt.k12.ma.us. The Public
       | Suffix List is a list of all known public suffixes._
       | 
       | > _The Public Suffix List is an initiative of Mozilla, but is
       | maintained as a community resource._
        
       | kristofferR wrote:
       | Is this actually a problem? From the Github page it seems like
       | the rate of invalid inclusion requests is very low, less than one
       | per day:
       | 
       | https://github.com/publicsuffix/list/pulls?q=label%3Awontfix...
        
         | kelnos wrote:
         | That's not the issue; addition requests volume has suddenly
         | gone way up because of this new Apple policy, and the
         | volunteers that run the PSL are not prepared for it.
        
       | throw14082020 wrote:
       | What is a PSL inclusion request? Public Suffix List?
        
         | pugworthy wrote:
         | Same question - what is PSL?
         | 
         | My best guess at the moment is Public Suffix List.
        
       | manzu wrote:
       | I'm just here to point the finger at Facebook, or anyone, for
       | finding this workaround of declaring your legitimate website as a
       | domain suffix just for tracking entropy purposes this is so
       | laughable. like my ford fiesta identifies as an apache attack
       | helicopter
        
         | tick_tock_tick wrote:
         | Apple is the one that declared this list to be the source of
         | truth. Facebook is just information customers of Apple's
         | decision.......
        
       | gruez wrote:
       | Can someone provide more context here? How does being added to
       | the PSL affect tracking? Why are businesses adding themselves to
       | the PSL en masse?
        
         | twobitshifter wrote:
         | PSL is used to determine the level that a unique domain is
         | registered at. This restricts cookies and privileges to that
         | domain. It's just a simple list because both .com and .co.uk
         | are valid suffixes. Ios14 is using this list to prevent apps
         | from tracking you across sites by limiting the data that can be
         | stored per site. If you can get your domain recognized as a
         | suffix as mysite.com then you can split information between all
         | higher level domains. client1.mysite.com and
         | client2.mysite.com. This allows you to store as much
         | information as you want.
        
           | TechBro8615 wrote:
           | The PSL has always been a giant hack and totally
           | unmaintainable in the long term. It's only a matter of time
           | before someone mistakenly relying on it for security purposes
           | gets owned by a rogue PR. Also, as mentioned in some of these
           | issues, browsers don't even update it on any sort of
           | guaranteed schedule.
        
             | jakear wrote:
             | The fun thing is you can s/PSL/DNS/g and the statement
             | still holds. Same for BGP
        
       | FemmeAndroid wrote:
       | This followup issue seems to have a more clear writeup,
       | especially for someone like me who is a bit out of the loop when
       | it comes to the PSL:
       | 
       | https://github.com/privacycg/private-click-measurement/issue...
        
         | vHMtsdf wrote:
         | The linked discussion makes me wonder, how much of our
         | existence on the internet is just an unintended consequence of
         | some minor engineering decision? Whim of an unknown engineer
         | creating or destroying million dollar industries down the
         | line...
        
         | djrogers wrote:
         | While it does have quite a bit of details, this followup issue
         | is clearly written by someone from FB or one of the other AdCos
         | who wants to point the finger back at Apple. The tone and
         | wording used here is rather rich and entitled.
        
           | [deleted]
        
           | pandemicsyn wrote:
           | you're not joking: https://github.com/privacycg/private-
           | click-measurement/issue...
           | 
           | >Who will vet such a list continuously at a global scale?
           | >Apple should. >Apple created this issue in the first place.
           | The need for multi-tenant websites to add themselves to the
           | PSL exists only because of the PCM design decision to limit
           | measurement to registrable domains. The urgency exists
           | because Apple's planned ATT enforcement.
        
           | romanhn wrote:
           | Ben Savage is a pretty high-level engineer from Facebook's
           | Ads org
        
           | dkonofalski wrote:
           | Seriously. I can see reasons that aren't entirely altruistic
           | for Apple in trying to increase these privacy protections but
           | trying to offload it back to Apple as if Facebook's abuse of
           | consumer data isn't the real reason for this is ridiculous.
        
           | wffurr wrote:
           | They seem to think that people can't really "opt out" of
           | "tracking" (scare quotes theirs). Talk about entitled.
        
             | dialtone wrote:
             | The quotes are entirely appropriate because adding some
             | domain to the PSL makes the subdomains siloed cookie-wise
             | so they can't share cookies and the PSL cannot use cookies
             | anymore. Since they can't share cookies you can't track
             | across even the same domain when added to the PSL.
             | 
             | This is a feature needed for sites like Rakuten, Shopify,
             | Alibaba that have multiple merchants under the same
             | domains.
             | 
             | Nothing to do with entitlement.
        
               | kelnos wrote:
               | FB seems to believe they are entitled to the ability to
               | track people on iOS. Apple is under no obligation to
               | allow that.
        
               | dialtone wrote:
               | Apple literally built a feature that requires addition to
               | PSL to support a usecase that was addressed multiple
               | times in the PrivacyCG meetings. How is this entitlement,
               | they are following the Apple requirements.
        
           | dswalter wrote:
           | According to the comments in the history of that user on
           | Github, it is someone who claims to be an engineer from
           | Facebook in an earlier post: https://github.com/WICG/trust-
           | token-api/issues/28#issue-6447...
        
         | marketingtech wrote:
         | This is fascinating to see Apple and Facebook engineers
         | politely yet publicly arguing over potential technical
         | implementations of Apple's privacy policies.
        
       | [deleted]
        
       | varispeed wrote:
       | To be honest Facebook should offer a tracking free version with
       | paid subscription. It is not acceptable that the only way to use
       | Facebook and contact your family is to sacrifice your own and
       | theirs privacy. When are we going to have a regulator step in and
       | tackle this? It doesn't seem that GDPR has helped much, so I
       | think more radical steps are needed. Such tracking that is being
       | done online would be illegal offline (stalking), so I don't see
       | how long this is going to go. It's not sustainable.
        
         | echelon wrote:
         | iPhone users are probably among Facebook's most valuable
         | advertising demographic (ie. lots of disposable income).
         | Apple's decisions to block tracking are hurting them in a big
         | way, and offering a paid subscription probably won't seem
         | attractive to users if Facebook prices it at the full value
         | lost.
         | 
         | We've trained people that everything is free. We can't get away
         | from that now that the genie is out of the bottle. Furthermore,
         | people might just decide Facebook isn't worth it for them at
         | the level of functionality they provide. As more churn happens,
         | the overall value of the network decreases.
         | 
         | Apple just checkmated Facebook.
        
           | dialtone wrote:
           | This has nothing to do with tracking to target ads. Facebook
           | doesn't need Apple to execute that, people share data with FB
           | voluntarily.
           | 
           | This is about measuring the impact of advertising while
           | following a standard published by Apple itself and covering
           | the usecase of big marketplaces with sub stores in it.
        
         | PeterisP wrote:
         | I don't think that such a paid subscription would be feasible.
         | Facebook currently earns more than 150 $/year on ads for each
         | of their US/Canada user _on average_ ; and iPhone users who
         | would be willing to pay for such services probably are worth
         | more than the average, so the appropriate market-determined fee
         | to replace invasive ad targeting would be quite large.
         | 
         | I don't think people would be willing to pay for tracking-free
         | Facebook more than they pay for Netflix.
        
           | varispeed wrote:
           | I don't think profits of a private company should be a
           | justification for such invasion of privacy. There is plenty
           | of ways they could make it work, but we need a legislation to
           | compel them to do so. That option should be mandated by law
           | even if it turned out to be niche.
        
       | sergiotapia wrote:
       | So much brain power and work wasted on this ad bullshit
        
         | amelius wrote:
         | Yes and ads also stimulate over-consumption which hurts the
         | planet.
         | 
         | The solution is to block all ads, or even better, ban them.
        
       | layoutIfNeeded wrote:
       | Why are we using a centralized list for determining who's an eTLD
       | and who's not? Why don't we store this metadata in the actual DNS
       | records?
        
       | marketingtech wrote:
       | This is a result of Apple limiting the entropy of marketing data
       | that can be received from a domain (defined as an eTLD+1) to 6
       | bits.
       | 
       | This causes problems for platforms like Shopify or marketplaces
       | like Alibaba or eBay that may have multiple sellers trying to run
       | ads on a domain and competing for the same small pool of entropy.
       | 
       | This solution? Leverage the "public suffix" list to define your
       | domain as an eTLD and give every seller a separate subdomain so
       | that everyone gets their own data entropy namespace.
       | 
       | Now every hosting provider or online marketplace is scrambling to
       | re-architect their site into subdomains with public suffixes to
       | maintain the status quo.
        
         | gsnedders wrote:
         | > This causes problems for platforms like Shopify or
         | marketplaces like Alibaba or eBay that may have multiple
         | sellers trying to run ads on a domain and competing for the
         | same small pool of entropy.
         | 
         | This is essentially https://github.com/privacycg/private-click-
         | measurement/issue....
         | 
         | Effectively it boils down to, "how can you distinguish the
         | seller from the website owner?", if you want to give both
         | seller and website owner entropy.
        
         | tekstar wrote:
         | Pretty much all Shopify shops have their own domains, only a
         | minority drive traffic to their .myshopify.com subdomain
        
           | bredren wrote:
           | I was a bit surprised that a shopify biz that could not be
           | bothered to use its own domain would be very concerned about
           | monitoring ad performance.
           | 
           | Seems someone would first effect to have a better branded
           | site. As in, a decent TLD.
           | 
           | And that if anything, this is a kick in the pants of an
           | ecommerce site to get its own domain(s) to deal with this.
           | 
           | Do I have that right?
        
             | 43920 wrote:
             | There's probably a decent number of sites that get most/all
             | of their traffic from impulse purchases off of Facebook
             | ads, and who have no actual branding. Obviously they should
             | go ahead and just get a domain name, but they likely
             | haven't had any reason to care up until this point either.
        
             | simlevesque wrote:
             | Well, I could own google.myshopify.com and be happy with it
             | but have no way to buy the .com
        
               | Macha wrote:
               | Just suck it up and buy google-calculatorstore.com or
               | whatever - if you're happy with the myshopify domain you
               | clearly don't care _that_ much.
               | 
               | Of course, that specific example, since Google is
               | trademarked and well known might get you on the wrong end
               | of Shopify's ToS or a UDRP request either way.
        
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       (page generated 2021-04-07 23:00 UTC)