JSCeal Hides Crypto Malware in V8 Bytecode
Check Point details JSCeal, a crypto-stealing malware delivered as compiled V8 bytecode, and built a decompiler pipeline to expose its capabilities.
JSCeal, tracked by Check Point Research since early 2025, is a cryptocurrency stealer delivered as heavily obfuscated JavaScript compiled to V8 bytecode (.jsc) and run by a bundled Node.js runtime. Check Point, presenting at Black Hat USA 2026, extended the open-source View8 decompiler into a pipeline that recovered readable code from 23 samples, revealing theft of browser credentials and cookies, Telegram sessions, keystrokes, screenshots, HTTPS traffic interception with attacker-controlled certificates, and automated Google account takeover. Targeted overrides rewrite content for Binance, Bybit, and Ledger users. Later samples added AES-256-CBC encryption with externally supplied keys and expanded targeting to macOS.
TasmScan: Continuation-Aware Taint Analysis for TVM Bytecode with Savelist Abstraction
TasmScan introduces source-free taint analysis for TON smart-contract bytecode, detecting 95.3% of defects with 96.8% precision and 17x speedup.
TasmScan is the first bytecode-level static analysis framework for the TON Virtual Machine, enabling cross-continuation data flow reasoning without source code by modeling savelist semantics through forward register analysis with formal over-approximation guarantees. It lifts bytecode into a typed intermediate representation (TASIR) and performs path-sensitive taint analysis. On a 208-contract benchmark with human-confirmed ground truth it detects 95.3% of defects across five classes at 96.8% precision, and resolves 294,546 dynamic continuation targets with 100% precision across 2,921 registry contracts. It achieves a 17x median speedup over symbolic-execution baselines.
Breaking the Seal: Static Deobfuscation of JSCeal’s Compiled V8 Bytecode
Check Point's hasherezade details static deobfuscation of JSCeal, a V8-bytecode stealer targeting cryptocurrency applications since March 2024.
JSCeal is an infostealer distributed as compiled V8 bytecode (.jsc) executed by a bundled Node.js runtime, aimed at cryptocurrency applications. Other vendors track the same family under the names WEEVILPROXY or MeadowLocust. Check Point Research has tracked the campaign since early 2024, with activity dating back to March 2024. The write-up presents a static approach to unpacking the bytecode without executing it.
New SLEEPWALKER Backdoor Waits for One Crafted Packet, Then Runs Its Own Bytecode
A new Windows backdoor dubbed SLEEPWALKER hides as ESET Management Agent's dpapi.dll, waits for a crafted network packet, then executes custom 23-instruction bytecode.
Researcher Dominik Reichel documented SLEEPWALKER, an unsigned 59,904-byte 64-bit Windows DLL that side-loads into ESET Management Agent's ERAAgent.exe while impersonating dpapi.dll. The implant monitors every network interface indefinitely for a specifically crafted trigger packet, then executes commands written in a custom 23-instruction bytecode language over six transports, including TCP, UDP, ICMP, SMB named pipes, raw promiscuous capture, and VMware VMCI. It has no embedded infrastructure, makes no outbound connections of its own, and requires prior local administrator access to install; no victims, attribution, or in-the-wild deployment are confirmed. Reichel assesses the design as consistent with a targeted, well-resourced operation, while ESET calls the scenario's security relevance negligible since it provides no new access path.
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.
CVE-2026-81578 + CVE-2026-82078 | PaperCut NG/MF Authentication Bypass and Unsafe Dynamic Class Loading Vulnerabilities
Two chained PaperCut NG/MF flaws, CVE-2026-81578 and CVE-2026-82078, enable pre-auth RCE, with active exploitation confirmed in customer environments.
PaperCut NG/MF is affected by CVE-2026-81578, an improper access control flaw (CVSS 4.0 8.8) allowing unauthenticated configuration changes, and CVE-2026-82078, an unsafe dynamic class loading flaw (CVSS 4.0 9.4) enabling arbitrary Java bytecode execution. Chained, they yield pre-authentication remote code execution on the PaperCut Application Server. PaperCut confirmed active exploitation and customer incidents, and Huntress observed exploitation starting August 26, 2026. Emergency Patch Release 2 is available for NG/MF v24-v26, with IOCs including suspicious pc-app.exe child processes, truncated server.log files, and AnyDesk installs.
IntentFuzz: A Protocol-Aware Fuzzer for Automated Invariant Violation Detection in Intent-Based Cross-Chain Bridges
IntentFuzz protocol-aware fuzzer recovers bridge structure from unannotated Solidity and confirmed 22 invariant violations across 24 real-world deployments.
IntentFuzz formalizes a taxonomy separating invariant violations from settlement exposures in intent-based cross-chain bridges, then recovers a bridge's intent structure and deposit/fill function roles from unannotated Solidity source. It classified deposit and fill functions with 100% recall and 82% combined precision, and achieved 100% recall and precision on 23 planted-bug mutants. Across 24 real-world deployments it confirmed 17 genuine invariant violations with heuristic-only input generation, rising to 22 with its LLM-assisted tier, spanning eight vulnerable GitHub repositories with findings reproducible against public deployed bytecode.