Cybersecurity researchers have uncovered an updated version of Hijack Loader, a malware loader with new features for evading detection. This latest version introduces call stack spoofing, which hides the origin of system and API calls. By manipulating the call stack, it replaces real stack frames with fabricated ones, making it harder to identify. Additionally, Hijack Loader now includes anti-VM checks, which detect virtual machines typically used for malware analysis. This addition helps attackers avoid detection in sandbox environments where malware is usually analyzed.
Hijack Loader, originally discovered in 2023, offers several capabilities designed to bypass security software and inject malicious code.
The loader can deliver second-stage payloads, including information-stealer malware, which compromises user data. In the new version, the malware targets a broader range of security solutions by including new processes to block. For example, it now includes “avastsvc.exe,” a component of Avast Antivirus, on the blocklist. By blocking this process, Hijack Loader introduces a delay in execution, making it harder for antivirus tools to detect its activities and providing attackers with more time to operate undetected.
The updated Hijack Loader also improves persistence by adding two new modules: ANTIVM and modTask. ANTIVM specifically targets virtual machine environments, ensuring that the malware can detect and avoid analysis in these environments. The modTask module, on the other hand, sets up scheduled tasks to maintain persistence on compromised systems. This ensures that Hijack Loader remains active and operational, even if the system is rebooted or temporarily cleaned.
These enhancements show the malware operators’ intent to refine Hijack Loader into a long-term threat, designed to evade detection and continuously infect systems over time.
Alongside Hijack Loader, a new malware family called SHELBY has surfaced, using GitHub as a command-and-control (C2) channel. SHELBY uses a unique method to communicate with attackers by making commits to a private repository on GitHub. These commits contain instructions for the infected systems, such as commands to exfiltrate data or load additional payloads. The malware uses a Personal Access Token (PAT) embedded within its binary to access the repository and execute commands. Notably, SHELBY uses sophisticated techniques to detect sandboxes and evade traditional monitoring tools, marking a new evolution in cyberattack strategies..
