Photo messaging service Snapchat downplayed an attack against its service outlined by last week by security researchers.
On Christmas Eve, Gibson Security publicly released details of two exploits against the service. The first was an attack against Snapchat’s ‘Find My Friends’ feature. Normally, Find My Friends allows users to look up their friends’ usernames by uploading the phone numbers in their devices’ address book and searching for accounts with matching numbers. In a proof-of-concept, the researchers abused that capability to do that on a massive scale, going through ten thousand phone numbers in approximately seven minutes.
In response to the disclosure, Snapchat called the attack theoretical, and said that it has taken steps against it.
“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,” the company stated in a blog post. “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.”
While the company may feel the severity of the exploit is exaggerated, in reality that is not the case, Gibson Security contended in an email to SecurityWeek.
“If someone has a rough idea of where you live, they can find you, provided your phone is on a nearby exchange,” according to Gibson Security. “You can also use this attack to generate large databases of users and phone numbers, which can link to profiles.”
In addition to the Find My Friends exploit, Gibson Security also posted a proof-of-concept for a second attack in which they were able to perform bulk registration of accounts, which they said could be used for speeding up the registration process or for spam.
“Many web services put one or more speed-bumps in the way of account creation, for example by sending an email containing a URL that needs to be visited to activate a new account, or by asking the applicant to solve a CAPTCHA,” blogged Sophos’ Paul Ducklin. “Spammers, scammers and other miscreants love services that make it easy to automate the creation of new users, and to recover information about existing users.”
Gibson Security criticized Snapchat for dragging its feet with its response, noting that they contacted the company months ago. Snapchat responded by praising security professionals “who practice responsible disclosure” and stating that the company has generally worked well with the researchers that have contacted it.