A newly identified threat actor called Dark Pink, also known as Saaiwc Group, is actively updating its custom toolset to expand its operations in Southeast Asia while evading detection.
Security researchers, including Group-IB and Tencent, have observed Dark Pink utilizing a malicious Microsoft Excel add-in for persistence. Dark Pink has targeted various entities, including government agencies in Brunei and Indonesia, a Thai military agency, educational institutions in Belgium, and government, military, and religious organizations across Vietnam, the Philippines, Malaysia, Cambodia, and Bosnia and Herzegovina.
The Excel add-in employed by Dark Pink establishes communication with the command-and-control infrastructure upon launching Excel, instead of device power-on, ensuring effective concealment.
The group downloads the Excel extension during the infection process from their GitHub page. Dark Pink also utilizes decryption techniques within its binaries to evade sandbox analysis and detection through static analysis.
Dark Pink’s tactics have drawn attention from cybersecurity experts, with Dutch company EclecticIQ noting improved obfuscation routines used by the threat actor. The group has shown interest in diplomatic engagements between European and Asia-Pacific countries, leading to speculation of a potential connection with Chinese state hackers.
Dark Pink follows a consistent infection chain, luring victims to download an ISO file containing a decoy MS Word document, a signed executable file, and a malicious DLL file. The DLL acts as a malware dropper, launching the KamiKakaBot malware through an MSBuild utility. Dark Pink communicates with KamiKakaBot via a Telegram channel and commands it to execute various actions, including stealing browser data and executing scripts.
After the public disclosure of their activities, Dark Pink shifted to a new GitHub account to store PowerShell scripts, zip archives, and custom malware. Analysis of the repository conducted by Group-IB revealed tools designed to steal information from the Zalo messaging app, as well as tools used for privilege elevation and launching PowerShell commands.
Dark Pink promptly deactivated the repository when URLs for its files were uploaded to VirusTotal, indicating a proactive effort to maintain operational security.
