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Facebook crawls links in PDFs you send in Messenger

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Re: Facebook crawls links in PDFs you send in Messenger

#101

This will keep happening until they enable e2e. I’ve had Facebook block several links sent in private message groups, to completely legal and safe sites (Messenger prints out an obscure API error and refuses to send the content). They have done this for a long time.

If you don’t mind what kind of fishy stuff are you messaging that you want to hide it so badly?

Re: Facebook crawls links in PDFs you send in Messenger

#104
post #85

Earlier quoted context omitted.

Other guy was right. Think about this easy scenario If (E2E_ENABLED) { SkipCrawler(); SkipContentChecks(); }

Again, it isn't to prove the encryption works, it is only a test that could prove that it doesn't work.

Ah, yea, I got the argument backwards. I thought he was saying if content wasn’t blocked that it proved encryption worked. Can’t prove the negative.

Re: Facebook crawls links in PDFs you send in Messenger

#106
post #65

This will keep happening until they enable e2e. I’ve had Facebook block several links sent in private message groups, to completely legal and safe sites (Messenger prints out an obscure API error and refuses to send the content). They have done this for a long time.

Worth noting WhatsApp also provides link previews now. Although it is supposedly e2e communication, the link previews are likely generated by reaching out to a similar facebook unfurl service. They can then have a single map of phone num -> links rendered between fb and whatsapp.

WhatsApp also scans pdf files you send to a contact. Easy to confirm as well: get some random pdf with chinese filename and chinese content. Send it to a contact. Watch the delay in send/receive. Now do the same for any random pdf that's all English. Watch the regular send/receive time occur.

The only conclusion: it takes a little time for a file that's flagged - based on its language - to pass the scanners?

Re: Facebook crawls links in PDFs you send in Messenger

#107
post #99
post #87

Earlier quoted context omitted.

Same can be done if e2e is enabled. Nothing prevents Facebook from sending links from client to a "validation" service. They do this already in WhatsApp for instance.

Maybe I'm being foolish, but isn't the point of e2e that Facebook wouldn't even know what you were sending (a link or otherwise), it being encrypted in flight?

Yes, but it's hard to trust e2e when keys go through a blackbox (Facebook's API), and clients are controlled by Facebook (closed source applications and JS).

It's better than no encryption, but not what technical people usually mean by e2e encryption

Re: Facebook crawls links in PDFs you send in Messenger

#108
post #5

Sidenote i wonder why FB doesnt launch a search engine since they crawl most of the web anyways

That would let people leave the Facebook platform and explore the open web.

They could create their own AMP-like tech to keep people on their website/application

EDIT: Actually they already did, it's called Facebook Instant Articles.

Re: Facebook crawls links in PDFs you send in Messenger

#109
post #15

Earlier quoted context omitted.

I remember the sheer awe when I first learned there was a huge open web outside of AOL. I'm sure people nowadays are aware of the rest of the web, but if the draw is minimal, they will likely get stuck in the same loops of well-trodden space.

A lot of the same people who kept that AOL walled garden alive, just migrated to Facebook. To them Facebook is the web, the restaurants they like are there, the tired celebs they worship are there and whatever crazed conspiracy theories someone told them at work or at church are under Facebook News. It's comfortable and I agree with you and like how you phrased it as "the same loops of well-trodden space."

People follow celebrities on Facebook? Don't they use Twitter for that?
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