Security News > 2022 > January > State hackers use new PowerShell backdoor in Log4j attacks

Hackers believed to be part of the Iranian APT35 state-backed group has been observed leveraging Log4Shell attacks to drop a new PowerShell backdoor.

As part of their research, the analysts also spotted something new in the form of a PowerShell modular backdoor named 'CharmPower.

The exploitation of CVE-2021-44228 results in running a PowerShell command with a base64-encoded payload, eventually fetching the 'CharmPower' module from an actor-controlled Amazon S3 bucket.

The core module keeps sending HTTP POST requests to the C2 that either go unanswered or receive a Base64 string which initiates the downloading of an additional PowerShell or C# module.

'CharmPower' is responsible for decrypting and loading these modules, and these then establish an independent channel of communication with the C2. The list of modules to be sent to the infected endpoint is generated automatically based on the basic system data retrieved by CharmPower during the reconnaissance phase.

Command Execution - Remote command execution module featuring Invoke-Expression, cmd, and PowerShell options.

News URL

https://www.bleepingcomputer.com/news/security/state-hackers-use-new-powershell-backdoor-in-log4j-attacks/