Security Experts:

Source Code of Android Banking Trojan "GM Bot" Leaked

The source code of an Android Trojan that allows cybercriminals to steal online banking credentials and other information from infected devices has been leaked.

The malware family whose source code has been published is known as GM Bot, MazarBot, SlemBunk, Bankosy, Acecard and Slempo. The threat is capable of displaying phishing pages on top of mobile banking applications in an effort to trick users into handing over their credentials.

GM Bot is also designed to intercept SMS messages and forward phone calls, which helps cybercriminals bypass additional bank security mechanisms. The SMS interception and call forwarding features can be used in combination with an option that allows fraudsters to lock a device’s screen in an effort to give them additional time to work.

Attackers can also use the threat to spy on victims (i.e. obtain their location via GPS), steal information entered on various websites, and delete data from the infected device.

According to IBM researchers, someone leaked the GM Bot source code in an effort to boost their reputation on an underground forum. The leaker posted a tutorial on the use of mobile malware for banking fraud, along with a password-protected archive containing the code for the GM Bot and its control panel.

“[The fraudster] indicated he would give the password to the archive only to active forum members who approached him. Those who received the password in turn passed it on to other, unintended users, so the actual distribution of the code went well beyond that discussion board’s member list,” IBM cybersecurity evangelist Limor Kessem wrote in a blog post.

Experts determined that the GM Bot control panel allows malware operators to manage stolen data, configure the Trojan, and create new phishing pages that are displayed on top of legitimate bank applications.

Attackers can use the control panel to access stolen information associated with credit cards, bank accounts, applications found on infected devices, online forms filled out by victims, and accounts for various online services. The stolen details can be sorted based on the country of origin.

It’s not uncommon for malware source code to get leaked, in many cases as a result of a dispute between cybercriminals, like in the case of the RIG exploit kit. Now that the GM Bot code has become available, experts believe we’ll likely see new Android threats based on it.

“The exposure of GM Bot’s code is comparable to the source code leaks of PC Trojans that include Zeus, SpyEye, Carberp and others. While GM Bot may not be as prolific as the major banking Trojans mentioned here, it is definitely a game changer in the realm of mobile threats. Its source code leak, similar to the Zeus leak, is likely to give rise to many variations of this sort of malware,” Kessem said.

Related: KINS Malware Toolkit Leaked Online

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Eduard Kovacs (@EduardKovacs) is a contributing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.