Windows TinyCC Shellcode Execution — Detection Rule
Detects abuse of Tiny-C-Compiler (TinyCC) for shellcode execution, where tcc.exe is renamed to masquerade as svchost.exe and used to compile and execute C source files containing shellcode. This technique was observed in the Lotus Blossom Chrysalis backdoor campaign, where attackers renamed tcc.exe to svchost.exe and executed conf.c containing Metasploit block_api shellcode with the flags -nostdlib -run. TinyCC is a legitimate C compiler, but its ability to compile and execute code on-the-fly makes it attractive to attackers seeking to evade detection. The combination of a renamed compiler binary executing from non-standard locations with suspicious flags is a strong indicator of malicious activity.