The cybersecurity landscape has witnessed a new threat with the emergence of the DocSwap malware, which disguises itself as a “Document Viewing Authentication App” to deceive users into installing it on their Android devices.
This sophisticated malware is suspected to be linked to a North Korean-backed Advanced Persistent Threat (APT) group, as revealed by the S2W Threat Intelligence Center in a recent report.
Malware Analysis and Features
The malicious app employs an XOR operation to decrypt a “security.db” file within its package.
It dynamically loads a DEX file and communicates with a Command and Control (C2) server to execute malicious commands.
These commands include keylogging and various forms of information theft, such as camera and microphone recording, as well as file downloading and deletion.
The app’s name and the presence of Korean-language strings suggest it primarily targets mobile users in South Korea.
However, its capabilities pose a threat to Android users worldwide.
Attribution and Detection
When initially discovered, the C2 infrastructure associated with DocSwap included a phishing page masquerading as CoinSwap.
By February 27, 2025, accessing the C2 address revealed a Naver favicon and the message “Million OK !!!!”, hinting at a possible connection to the Kimsuky group, a known North Korean-backed threat actor.
According tot the Report, The S2W Threat Research and Intelligence Center has designated the threat actors using DocSwap as “puNK-004,” part of their tracking efforts for unidentified threat groups linked to North Korea.
To protect against DocSwap, users should exercise caution when installing apps from unknown sources and avoid executing suspicious links or email attachments.
The malware’s ability to perform keylogging through accessibility services and its communication with the C2 server for malicious commands underscore the need for robust security measures.
Organizations and individuals are advised to stay vigilant and implement threat detection systems capable of identifying such advanced threats.
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