Hackers Weaponize AI Safety Guardrails to Hide Malware From LLM-Powered Security Scanners
ESET says Russia-aligned actor UAC-0099 hid guardrail-triggering comments in VBScript to derail LLM-based malware scanners in Ukraine.
ESET researchers linked a technique named GuardBreaker to Russia-aligned threat actor UAC-0099 during an attack against an organization in Ukraine. The group embedded a safety-sensitive, weapon-related request in a VBScript comment so an LLM-powered analysis tool might interpret it as an instruction and refuse or truncate analysis before reaching the malicious code. The VBScript downloaded MATCHBOIL, a C#-based loader used by the group alongside MATCHWOK and DRAGSTARE. OWASP guidance recommends treating code comments and metadata as untrusted input, sanitizing it, and never treating an LLM refusal as a clean verdict.
- GuardBreaker uses indirect prompt injection via comments to evade AI security scanners
- UAC-0099 previously targeted Ukrainian government, defense, transportation, and energy sectors
- Similar instruction-flooding tricks found in malicious PyPI and npm packages
- Defenders should correlate LLM analysis with signatures, sandboxes, EDR, and human review
From the original article
3 min read at gbhackers.com
Threat actors are adapting malware not only for conventional endpoint defenses and sandboxes, but also for large language model-powered tools increasingly used to triage suspicious code. ESET researchers linked the activity to Russia-aligned threat actor UAC-0099, which used the method during an attack against an organization in Ukraine. The group inserted a safety-sensitive, weapon-related request […]
By Mayura Kathir · gbhackers.com
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