Researchers have disclosed a new offensive framework referred to as Manjusaka that they call is a "Chinese sibling of Sliver and Cobalt Strike."
"A fully functional version of the command-and-control (C2), written in Golang with a User Interface in Simplified Chinese, is freely available and can generate new implants with custom configurations with ease, increasing the likelihood of wider adoption of this framework by malicious actors," Cisco Talos said in a new report.
Sliver and Cobalt Strike are legitimate adversary emulation frameworks that have been repurposed by threat actors to carry out post-exploitation activities such as network reconnaissance, lateral movement, and facilitating the deployment of follow-on payloads.
Written in Rust, Manjusaka -- meaning "cow flower" -- is advertised as an equivalent to the Cobalt Strike framework with capabilities to target both Windows and Linux operating systems. Its developer is believed to be located in the GuangDong region of China.
"The implant consists of a multitude of remote access trojan (RAT) capabilities that include some standard functionality and a dedicated file management module," the researchers noted.
Some of the supported features involve executing arbitrary commands, harvesting browser credentials from Google Chrome, Microsoft Edge, Qihoo 360, Tencent QQ Browser, Opera, Brave, and Vivaldi, gathering Wi-Fi passwords, capturing screenshots, and obtaining comprehensive system information.
It's also designed to launch the file management module to carry out a wide range of activities such as enumerating files as well as managing files and directories on the compromised system.
On the other hand, the ELF variant of the backdoor, while including most of the functionalities as its Windows counterpart, doesn't incorporate the ability to collect credentials from Chromium-based browsers and harvest Wi-Fi login passwords.
Also part of the Chinese language framework is a C2 server executable that's coded in Golang and is available on GitHub at "hxxps://github[.]com/YDHCUI/manjusaka." A third component is an admin panel built on the Gin web framework that enables an operator to create customized versions of the Rust implant.
The server binary, for its part, is engineered to monitor and administer an infected endpoint, in addition to generating the appropriate Rust implants depending on the operating system and issuing the necessary commands.
That said, the chain of evidence suggests that it's either under active development or its components are offered to other actors as a service.
Talos said it made the discovery during its investigation of a maldoc infection chain that leverages COVID-19-themed lures in China to deliver Cobalt Strike beacons on infected systems, adding the unnamed threat actor behind the campaign also used the implants from the Manjusaka framework in the wild.
The findings arrive weeks after it emerged that malicious actors have been observed abusing another legitimate adversary simulation software called Brute Ratel (BRc4) in their attacks in an attempt to stay under the radar and evade detection.
"The availability of the Manjusaka offensive framework is an indication of the popularity of widely available offensive technologies with both crimeware and APT operators," the researchers said.
"This new attack framework contains all the features that one would expect from an implant, however, it is written in the most modern and portable programming languages. The developer of the framework can easily integrate new target platforms like MacOSX or more exotic flavors of Linux as the ones running on embedded devices."