Cybersecurity researchers have identified a worrying trend where hackers are exploiting shortcut files to distribute CHM malware. Shortcut files, commonly used and trusted, are now being weaponized to execute malicious code, effectively bypassing standard security protocols. This allows attackers to deploy malware without arousing suspicion, making systems vulnerable to data theft and unauthorized access. The recent discoveries by ASEC and AhnLab spotlight the active abuse of these weaponized files targeting Korean users specifically, with malware designed to steal sensitive information.
The attack involves CHM files that, when executed, display a help document while concurrently running a malicious script. This script performs several functions such as creating and initiating Link.ini within the user’s profile. It then connects to a remote server via a modified URL to download and execute additional malicious scripts. These scripts are cleverly concealed using advanced obfuscation techniques, making them hard to detect with standard anti-malware tools.
The sophistication of this malware is further demonstrated by its execution process, which includes the exfiltration of system information, files, and running processes. It uses encoded PowerShell scripts to perform its operations, enhancing its stealth and complexity. The malware registers itself to run periodically, ensuring persistence in the infected system and continuous data theft. This involves keylogging and clipboard data capture, with the stolen data sent back to the attacker’s server before being erased locally to avoid detection.
Given the specific targeting of Korean users, it is imperative for individuals and organizations within this demographic to be vigilant. The attackers are employing highly sophisticated methods to hide their activities, using formats like LNK, DOC, and OneNote files that seem innocuous but are in fact laced with malware. Users are advised to be particularly cautious about opening files from unknown or suspicious sources, as these could potentially be part of this malware distribution campaign.
