Iranian APT OilRig Uses New Saitama Backdoor

In late April 2022, Fortinet and Malwarebytes security researchers discovered a malicious Excel document sent by the OilRig hacker group (also known as APT34, Helix Kitten, and Cobalt Gypsy) to a Jordanian diplomat to inject a new backdoor called Saitama.

The phishing email came from a hacker disguised as an employee of the IT department of the Ministry of Foreign Affairs. The attack was discovered after the recipient forwarded the email to a real IT employee to verify the authenticity of the email.

According to research notes provided by Fortinet, the macro uses WMI (Windows Management Instrumentation) to query its command and control (C&C) server and is capable of producing three files: a malicious PE file, a configuration file, and a legitimate DLL file. Written in .NET, the Saitama backdoor uses the DNS protocol to communicate with C&C and exfiltrate data, which is the stealthiest method of communication. Methods of masking malicious packets in legitimate traffic are also used.

Let me remind you that we also reported that Cross-platform SysJoker backdoor attacks Windows, macOS and Linux and that Hackers send resumes with more_eggs malware to recruiters.

Malwarebytes also published a separate backdoor report, noting that the entire program flow is explicitly defined as a state machine. In simple words, the machine will change its state depending on the command sent to each state.

States include:

1. The initial state in which the backdoor receives the launch command;
2. “Live” state, in which the backdoor connects to the C&C server, waiting for a command;
3. Sleep mode;
4. Receiving state, in which the backdoor accepts commands from the C&C server;
5. Operational state in which the backdoor executes commands;
6. Submission state, in which the results of command execution are sent to attackers.