Iranian Cyberspies Deployed New Backdoor to 34 Organizations

Iran-linked cyberespionage group Charming Kitten has been observed infecting 34 victims with a new backdoor, cybersecurity firm ESET reports.

Believed to be operating on behalf of Iran’s Islamic Revolutionary Guard Corps (IRGC) and also tracked as APT42, Ballistic Bobcat, Mint Sandstorm (formerly Phosphorus), and NewsBeef, Charming Kitten has been targeting activists, government organizations and journalists for more than a decade.

Recently, the advanced persistent threat (APT) actor has been engaging in financially motivated ransomware operations and was seen targeting critical infrastructure organizations in the US last year.

Since 2021, the newly identified Sponsor backdoor has been deployed mainly against organizations in Israel, in the automotive, engineering, financial services, healthcare, manufacturing, media, technology, and telecommunications sectors.

For initial access, Charming Kitten exploited known vulnerabilities in internet-facing Microsoft Exchange servers. However, many of the identified victims lack an obvious intelligence value, suggesting that the attacks were not targeted, but rather a scan-and-exploit operation.

This theory is also supported by the fact that 16 of the 34 identified victims were compromised by other threat actors as well, ESET notes.

Written in C++, the Sponsor backdoor is executed as a persistent service that uses configuration files dropped on the disk, which contain an interval for contacting the command-and-control (C&C) server to receive commands, and a list of C&C servers.

The backdoor gathers system information and sends it to the C&C server, which responds with a node ID. The malware also collects the host’s Windows domain and the current username.

Sponsor’s operators can issue commands to retrieve the backdoor’s process ID, execute a command on the host system, receive files and execute them, sleep, and to update the list of C&Cs and predetermined check-in intervals.

Charming Kitten has been observed using two versions of the backdoor, with no changes in functionality between them. As part of the campaign, the APT used previously known infrastructure, as well as a new C&C server and multiple IPs to deploy various open source tools in support of its operations.

“The group continues to use a diverse open source toolset supplemented with several custom applications, including its Sponsor backdoor. Defenders would be well advised to patch any internet-exposed devices and remain vigilant for new applications popping up within their organizations,” ESET notes.

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