Jan 2, 2014 - 15:51:00 - Finding Friends with Phone Numbers


Occasionally computer security professionals and other helpful people reach out to us about potential bugs and vulnerabilities in Snapchat. We are grateful for the assistance of professionals who practice responsible disclosure and we’ve generally worked well with those who have contacted us.

This week, on Christmas Eve, a security group posted documentation for our private API. This documentation included an allegation regarding a possible attack by which one could compile a database of Snapchat usernames and phone numbers. 

Our Find Friends feature allows users to upload their address book contacts to Snapchat so that we can display the accounts of Snapchatters who match the phone numbers found in the address book. Adding a phone number to your Snapchat account is optional, but it’s helpful for allowing your friends to find you. We don’t display the phone numbers to other users and we don’t support the ability to look up phone numbers based on someone’s username.

Theoretically, if someone were able to upload a huge set of phone numbers, like every number in an area code, or every possible number in the U.S., they could create a database of the results and match usernames to phone numbers that way. Over the past year we’ve implemented various safeguards to make it more difficult to do. We recently added additional counter-measures and continue to make improvements to combat spam and abuse.

Happy Snapping!

This is so amazing.

Step 1: Security researchers find huge holes in Snapchat (Refresher: Snapchat are the “ephemeral messaging wait what do you mean screenshots exist???” people) API with which you can steal their users phone# and associated user name, Snapchat does nothing, presumably because like most IT companies, they do not give a shit about their users data, they just want to be able to pretend they do.

Step 2: Security researchers eventually post about it and post a proof of concept exploit.

Step 3: Snapchat…. does nothing, writes a blog post detailing how their app is TOTALLY secure and how the security researchers totally cannot do what their exploit that is right there and that you can run actually literally does - i.e. they lie about it and pretend there is no problem when there obviously is one.

Step 3.5: Time passes, somebody presumably runs the exploit code, which as it turns out, works.

Step 4: The phone numbers and associated user IDs of a large part of Snapchats userbase are now on the internet, for anybody who is curious to download! Congratulations, Snapchat: You’re a bunch of fucking assholes! Still no reason to care, though, because consequences for you will be minimal! A shame for your users, though, wouldn’t want to be any of them!

Happy Snapping!

p.s. when do we get a law that penalizes cavalier handling of user data like this? Probably never, because any attempt to pass laws that may actually improve network security but are a bother for companies get shot down real quick!

Reviewer comments

  1. lomolif reblogged this from halcy
  2. lovehabiblove reblogged this from snapchatme
  3. abdiraxmaan reblogged this from snapchatme
  4. sabrinabizzleeckrichjb reblogged this from snapchatme
  5. hctr31690 reblogged this from snapchatme
  6. edithigunborxxx123 reblogged this from snapchatme
  7. rudy-calmez reblogged this from snapchatme
  8. fourfatasses reblogged this from halcy
  9. camylleme reblogged this from snapchatme
  10. mellow937 reblogged this from snapchatme
  11. ziltoidsmug reblogged this from halcy and added:
    snapchat was compromised. might not be a bad idea to look at your account to see what’s up
  12. cmlh reblogged this from snapchatme and added:
    Since I have some experience in disclosing vulnerabilities in Social Media I would agree with SnapChat’s position in...
  13. wonder-meathead reblogged this from jessesbizarreventura and added:
    >expecting big name companies with millions of dollars and high paid lawyers to actually give a fuck about you, or your...
  14. jessesbizarreventura reblogged this from halcy
  15. halcy reblogged this from snapchatme and added:
    This is so amazing. Step 1: Security researchers find huge holes in Snapchat (Refresher: Snapchat are the “ephemeral...
  16. gloria1234love reblogged this from snapchatme


Somewhat average だめ人間 masters CS student at University of Karlsruhe who likes to make demos. I enjoy anime, various video games, touhou project, oversized pixels and DIGITAL SPORTS .

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