ZeroHour

Search: “ESET”

262 stories

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.

GBHackersupdated · 5d agofirst · 6d agoThreat actor in the wild 2 sources1

GentleKiller targets more than 400 security processes across 48 products

ESET details the Gentlemen ransomware gang's in-house GentleKiller EDR-killer framework targeting over 400 security processes across 48 products, supplied to affiliates.

ESET analyzed the Gentlemen ransomware gang's in-house GentleKiller EDR-killer framework, confirmed through an internal data leak from May 2026. The framework has at least eight variants impersonating legitimate security products and abusing vulnerable or malicious kernel drivers, targeting more than 400 process names across 48 security products. Gentlemen emerged in late 2025, became one of the five most active ransomware gangs in Q1 2026, offers affiliates a 90% ransom share, and practices double extortion using Go-based and C-based ESXi encryptors. The suite also reuses outside tools including HexKiller, ThrottleBlood, and HavocKiller, unified by a shared evasion layer that mimics well-known security vendors.

Help Net Security · 24d agoRansomware in the wild