Malware Abuses Trust to Spread on Twitter

Researchers at Trusteer say a notorious piece of financial malware is now hitting Twitter with a new mission – to break into the accounts of unsuspecting users.

According to Trusteer, the malware is known as TorRAT. While normally it is focused on financial information, a new iteration has been seen hijacking the Twitter accounts of those it infects.

“The malware launches a Man-in-the-Browser (MitB) attack through the browser of infected PCs, gaining access to the victim’s Twitter account to create malicious tweets,” blogged Dana Tamir, director of enterprise product marketing at Trusteer.  

The malware spreads using malicious links accompanied by tweets written in Dutch, such as “Onze nieuwe koning Willem gaat nog meer verdienen dan beatrix. check zijn salaris,” which translates to “Our new King William will earn even more than Beatrix. Check his salary” in English. While the attack is targeting the Dutch market right now, this type of attack “can be used to target any market and any industry,” Tamir noted.

“The attack is carried out by injecting Javascript code into the victim’s Twitter account page,” according to Tamir. “The malware collects the user’s authentication token, which enables it to make authorized calls to Twitter’s APIs, and then posts new, malicious tweets on behalf of the victim.”

The malware posts the tweets on behalf of the user directly into the live Twitter session the user has,” explained Yishay Yovel, vice president of Trusteer.

“This session tampering is the same approach hackers use to create fake financial transactions targeting user logs into their online banking account and a live session exists between the user and the bank,” he told SecurityWeek.

“We don’t often see malware spreading on Twitter the way this malware is,” Yovel added. “This attack is similar to when an email account gets compromised – the recipients on the email contact list are likely to click a malicious link in an email because they trust the user. The malware on Twitter uses this same method of exploiting the trusted relationship between the Twitter handle owner and the followers.”

That makes it particularly difficult to defend against, Tamir noted.

“Twitter users follow accounts that they trust,” she said. “Because the malware creates malicious tweets and sends them through a compromised account of a trusted person or organization being followed, the tweets seem to be genuine.”