Astaroth Trojan Disguises as JPEG, GIF File Abuses OS and Antivirus Process to Steal Data

A new unique campaign abuses system native OS process and security software to steal passwords and personal information. Threat actors disguise the Astaroth Trojan payload as JPEG, GIF, and extensionless to avoid file detections.

The campaign especially targets the users in Brazil and the initial infection starts with a phishing-based campaign.

Researchers form cybereason observed a major difference between the new and the old campaign and the attack has improved significantly when compared to the previous campaign. With this new campaign, attackers use the BITSAdmin tool to download the final payload.

The campaign begins with the phishing email with a .7zip attachment contains a .lnk file that initiates the malware process, then it uses legitimate windows tool wmic.exe to initiate an XSL Script Processing attack.

According to researchers, the XSL Script is highly obfuscated to hide its activities from Antivirus and to evade analysis. Then the XSL Script abuses the BITSAdmin admin tool to download the malicious payload.

Once the malicious payload executed in the machine it looks for avast installation and injects a malicious mode into the avast process for loading other modules and gathering information about the machine. The Second module looks to exfiltrate the password and other information.

If the trojan executed successfully it exfiltrates the following information

users keystrokes
Intercept OS calls
ail account passwords
Messenger accounts
Internet Explorer passwords
Infiltrates clipboad information

The malicious process infects for a certain time through target process it deletes itself and then continue the process periodically. Once the system infected with the malware it continues exfiltrating information and sends to C2 server.