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CASHEWS: Source Preprocessor for LLM-based Malicious Package Detection

CASHEWS preprocessor boosts LLM-based malicious npm package detection, raising coverage to 98.8-100% and cutting false negatives by up to 18.6 points.

Researchers present CASHEWS, a JavaScript preprocessor for LLM-based malicious package detection that deobfuscates code iteratively, extracts bundled modules and dynamically executed code, identifies malicious sinks, and computes backward slices to produce compact detector input. Threat actors evade LLM detectors by exploiting limited context windows with high token-density obfuscation and by bundling malicious code with benign packages, as seen in supply-chain attacks such as Shai-Hulud. Across 512 large package files, two scanner types, and three LLMs, CASHEWS raised analysis coverage from 69.1-85.7% to 98.8-100% and reduced false-negative rates by up to 18.6 percentage points. Median preprocessing time is 30 seconds while net analysis cost drops 34.6%.

arXiv cs.CR · 21h agoResearch

The extension you never installed: KREMLIN forges Chrome's own integrity checks to steal banking sessions

Elastic details KREMLIN, a Brazilian banking malware whose malicious Chrome/Edge extension forges Chromium integrity checks to steal sessions.

Elastic Security Labs tracked operation REF9334 and its KREMLIN toolkit, a Brazilian banking malware campaign impersonating twelve banks across seven campaigns since May 2025. The infection chain uses multi-stage obfuscated JavaScript loaders with sandbox checks (file and process counting), scheduled-task persistence, and an Ethereum smart contract acting as a dead-drop resolver for C2 and payload URLs, abusing Archive.org for hosting. The malicious browser extension bypasses Chromium integrity mechanisms by manipulating Secure Preferences and regenerating required HMACs and App-Bound encrypted hashes. Threat Command disrupted over 1,500 infections by registering the kill-switch canary domain.

Elastic Security Labs · 3d agoMalware in the wild

Security Affairs newsletter Round 594 by Pierluigi Paganini – INTERNATIONAL EDITION

Weekly Security Affairs newsletter aggregates top stories including Cisco FMC exploitation, Qilin ransomware, Chrome zero-days, and Berlin leak.

Pierluigi Paganini's Security Affairs newsletter Round 594 (International Edition) rounds up the week's security headlines. Topics include attackers exploiting a critical Cisco FMC flaw to deploy Qilin ransomware, SonicWall mass exploitation linked to a UK council attack, multiple CISA KEV additions, Chrome zero-days used by four nation-state actors, a $320 million Liquid Network theft, and a Berlin ransomware data leak. It also covers AI security items such as agent sandbox failures and distillation campaigns by Chinese AI firms.

Security Affairs · 3d agoIndustry in the wildCVE-2026-42016CVE-2026-42018CVE-2026-82329+1 CVEs1

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