Description

The threat actor known as Mysterious Elephant, also referred to as APT-K-47, has been observed utilizing an upgraded version of the Asyncshell malware in its recent campaigns. The group, active since at least 2022 and originating from South Asia, primarily targets entities in Pakistan. Its tactics and tools show overlaps with other regional threat groups, such as SideWinder, Confucius, and Bitter. The Knownsec 404 team uncovered that the group's latest campaign employed Hajj-themed phishing lures to trick victims into executing malicious payloads disguised as Microsoft Compiled HTML Help (CHM) files. These files were included in ZIP archives alongside a hidden executable, presented as information about the Hajj policy for 2024. When victims opened the CHM file, it displayed a decoy document a legitimate PDF hosted on Pakistan’s Ministry of Religious Affairs and Interfaith Harmony website while stealthily executing a malicious binary in the background. This campaign delivered Asyncshell, a malware designed to establish a cmd shell with a remote server. Knownsec 404 identified overlaps between the malware's functionality and previous versions used by Mysterious Elephant since mid-2023. The group has released four versions of Asyncshell to date, incorporating capabilities to execute cmd and PowerShell commands. Early infection chains leveraged vulnerabilities in WinRAR to initiate malware deployment. Later iterations evolved to use HTTPS instead of TCP for command-and-control (C2) communications and employed updated techniques, such as using Visual Basic Scripts to display decoy documents and executing tasks via scheduled processes. In its recent operations, Mysterious Elephant has adopted a more sophisticated approach by replacing fixed C2 servers with variable C2 configurations. The change, which leverages disguised service requests to dynamically control the final shell server address, underscores the group’s focus on enhancing Asyncshell’s attack chain and payload capabilities.