Zeus Malware Hidden In Fake LinkedIn Messages

Prospective employers and job applicants are not the only ones using LinkedIn for research. Cyber-criminals are increasingly using the social networking site for professionals to identify potential victims, according to security experts.

Security firm Trusteer uncovered spam messages designed to look almost the same as legitimate notification messages from LinkedIn, Trusteer CEO Mickey Boodaei wrote in the company blog on June 2. When users click on the link in the message, usually an invitation to connect with someone, they are redirected to a malicious server in Russia serving up malware.

Pilfering LinkedIn Company Profiles

Through LinkedIn, cyber-criminals can build a profile of targeted enterprises and locate key people within the organisation. The spam messages sent to those people could be used to install malware which could steal login credentials or other confidential information.

“Sounds unlikely? Well, think again,” Boodaei said.

The fraudulent LinkedIn messages take users to a salesforceappi.com domain. Despite the name, the domain has nothing to do with Salesforce.com. It was registered May 31 and the server associated with the IP address is based in Russia.

The users are then hit by drive-by-download attacks based on the BlackHole exploit kit to install Zeus 2 Trojan on the computer, according to Trusteer. This Zeus variant transmits the stolen data to a server in Zhejiang, China.

While commonly associated with banking fraud, Trusteer’s Boodaei said Zeus has other capabilities and can allow attackers to access workstations and other data stored on the corporate network.

“We’ve recently seen evidence of Zeus targeting enterprise networks in order to steal proprietary information and to gain unauthorised access to sensitive systems,” Boodaei said.

A recent Trusteer survey found that 68 percent of enterprise users who receive a fake LinkedIn message are likely to click on it. It is not entirely their fault, as LinkedIn and other social networking sites “educate us to click on links “, Boodaei said. The sites regularly send out calls for actions to encourage users into going back to the site.

“This is extremely dangerous as many users almost automatically click on these links without trying to verify their authenticity,” Boodaei said, especially considering that LinkedIn hides the link behind a button, which makes it even harder to check the URL.

It is increasingly becoming harder to identify phishing and malicious email messages as attackers get more creative. Trusteer recommends users to train themselves to never opening emails from social networking sites, let alone clicking on the links in those messages. Users should access the social networking Website by typing the address manually, and handle all the notifications from the site directly, Boodaei said.

Recent attacks against RSA and Oak Ridge National Laboratory tricked employees into opening attachments or clicking on links in malicious messages. “Cyber criminals are putting a great deal of effort in these attacks and are unfortunately successful,” Boodaei said.

There have been several variations of the LinkedIn scam, with researchers at Cisco Systems reporting a similar campaign last autumn.

The BlackHole exploit kit locates vulnerabilities on a computer and prepares a customised payload depending on operating system and installed software, according to Bitdefender. It used to sell for $1,500 (£900) back when it appeared on the black market a year ago, but nowadays can be obtained for free.