Mobile, TDR, Endpoint Security

Snapchat flaw lets researcher crash iPhone with flood of messages

By exploiting a flaw in photo messaging service Snapchat, an attacker could render victims' iPhones temporarily inoperable by flooding their account with messages, a researcher found.

In a Saturday blog post, Jaime Sanchez, a security researcher in Spain, explained that the denial-of-service (DoS) attack was possible due to Snapchat's method of creating security tokens for user authentication.

The tokens, which are used in place of passwords for authenticated users, don't expire, Sanchez wrote. By exploiting the vulnerability using a custom script he created, Sanchez was able to reuse Snapchat security tokens to send new messages to account holders.

Sanchez demonstrated the attack method in a YouTube video, carrying out the DoS on a Los Angeles Times reporter's phone. On Friday, the Times published an article on the vulnerability.

The reporter was forced to shut down and restart his phone after Sanchez sent 1,000 Snapchat messages within five seconds to his account, Sanchez's blog post said.

“I've been using for the attack one token create[d] almost one month ago,” Sanchez wrote. “So, I'm able to use a custom script I've created to send snaps to a list of users from several computers at the same time.”

Sanchez later added that a targeted iPhone may still be disabled for awhile, even after a user restarts their device.

"As you've seen on the video, on iPhone, it will crash you[r] phone and when it powers up, it still hangs until the attack is over," he explained.

SCMagazine.com reached out to Snapchat, but did not immediately hear back from the company. On Monday, the service did, however, say via its Twitter account that it addressed the issue “immediately after the LA Times publication.”

Through his research, Sanchez also found that the attack method could be used against Android devices, though it wouldn't cause them to crash, but “slow their speed” of operation.

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