The Iran-linked cyber espionage group known as Charming Kitten, also referred to as APT35, Phosphorus, Newscaster, and Ajax Security Team, has been observed by security firm Volexity using an updated version of their PowerShell backdoor called POWERSTAR in a spear-phishing campaign.
Charming Kitten gained notoriety in 2014 for orchestrating an extensive online spying campaign using social media, and they have been active since at least 2011, targeting individuals, organizations, and entities in the Middle East, United States, U.K., Israel, Iraq, and Saudi Arabia.
Volexity’s recent report reveals that Charming Kitten has been evolving their malware alongside their spear-phishing techniques, employing enhanced anti-analysis measures in the POWERSTAR implant.
Volexity first detected the POWERSTAR backdoor in 2021, distributed in various ways, including through malicious macros embedded in DOCM files and spear-phishing messages with password-protected RAR files containing LNK files.
Charming Kitten has transitioned from using cloud-hosting providers like OneDrive and Dropbox to privately hosted infrastructure such as Backblaze and IPFS.
The group targeted an organization that published an article related to Iran, initiating contact with victims under the guise of sharing a document on U.S. foreign policy. The interaction progressed with benign emails and questions until the victims received a password-protected RAR file containing a malicious LNK file labeled as a “draft report.”
To evade analysis, Charming Kitten separates the decryption method from the initial code and avoids writing it to disk, hindering detection of the backdoor’s functionality.
The POWERSTAR backdoor enables remote execution of PowerShell and CSharp commands, achieves persistence through startup tasks, Registry Run keys, and PowerShell scripts, and gathers system information while also capturing screenshots and enumerating running processes. The group has expanded its cleanup module to remove traces of the infection.
By continuously refining their malware, Charming Kitten aims to make detection more challenging and secure their cyber espionage operations.
