Security researchers have developed a new malware process injection technique called "Waiting Thread Hijacking" (WTH), which executes harmful code within legitimate processes while avoiding detection by security measures. This method improves upon traditional Thread Execution Hijacking by using a different sequence of operations that bypasses commonly monitored API calls.
WTH involves allocating memory and injecting malicious payloads using standard functions, identifying dormant threads within the target process, acquiring thread context with less suspicious permissions, and overwriting the return address on the stack with the injected shellcode. The technique ensures stability by preserving the original state of the thread and allows it to resume normal operations after executing the malicious code.
Additionally, WTH employs an obfuscation technique that distributes its steps across multiple child processes to evade behavioral detection systems. While WTH can avoid many conventional detection triggers, it is not completely immune, as some Endpoint Detection and Response (EDR) solutions can block unauthorized memory writes. Check Point Research has observed that WTH is effective against certain EDRs while others can block it but not older methods, illustrating the variability in EDR capabilities.