VMware ESXi - Obfuscated Shell Command Decode and Execute
Detects obfuscated shell command execution on VMware ESXi as hunted by CrowdStrike, where attackers hide esxcli commands (e.g. syslog config reset for log evasion, vm process list for recon) behind decode-and-execute wrappers such as printf hex/octal escapes, awk BEGIN blocks (chr/ord/xor/zero-width-unicode/morse/binary decoders), python -c chr() reconstruction, sed/od character-reversal ciphers, and $TERM/$SHELL substring reassembly, frequently invoking /usr/lib/vmware/busybox/bin/busybox or staging output in hidden /vmfs/volumes//.sys files before piping the reconstructed command into sh. This is a living-off-the-land technique used to evade detection and hinder forensic reconstruction of attacker activity on ESXi hosts, and has been observed enabling syslog exfil-log evasion and VM/hypervisor reconnaissance.
YARA-L
