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Guildma (Astaroth) malware infection from Brazilian Portuguese email, (Tue, Sep 1st)

Guildma (Astaroth) malware spread via geofenced Brazilian Portuguese phishing emails, using zip archives, shortcuts, and AutoIt loaders.

SANS researchers documented a Guildma (Astaroth) malware infection initiated on 2026-08-31 by a malicious Brazilian Portuguese email offering a DocuSign-themed PDF. The delivery link is geofenced to Brazil and requires Brazilian Portuguese browser and OS language settings, otherwise serving a legitimate installer. The infection chain uses a zip archive containing a Windows shortcut that retrieves a DLL saved as an alternate data stream, which installs a compiled AutoIt package for persistence. Unique SHA-256 indicators and HTTPS traffic to Azure-hosted and .cfd domains were observed, with prior reports noting the campaign's abuse of GitHub.

SANS Internet Storm Center · 14d agoMalware in the wild

"Blank Slate" Campaign Takes Advantage of Hosting Providers to Spread Ransomware

Unit 42 profiles the Blank Slate malspam campaign: blank emails with double-zipped attachments delivering Cerber ransomware while cycling abused hosting provider domains.

The Blank Slate campaign sends empty emails containing double-zipped archives with macro-enabled Word documents or JavaScript files that launch PowerShell to download ransomware, primarily Cerber, and occasionally Sage 2.0 or Locky. Unit 42 observed 555 campaign domains over seven months, with actors repeatedly registering new domains and cycling abuse of legitimate hosting providers after takedowns. In a five-day January-February 2017 window, at least eight domains across seven IP addresses were observed hosting Cerber payloads.

Palo Alto Unit 42 · Aug 17, 2026Threat actor in the wild1

Locky Ransomware Installed Through Nuclear EK

Unit 42 reports Locky ransomware delivered through the Nuclear exploit kit using Flash exploits, adding a drive-by path to existing malspam distribution.

Unit 42 observed Locky ransomware being delivered by the Nuclear exploit kit in March 2016 via Flash exploits, following February reports of Neutrino EK distributing Locky. Infections follow a drive-by chain through a gate to the Nuclear EK, which either installs Locky directly or drops a downloader that retrieves it from another domain. Locky retains two distribution paths: malspam with malicious Office macros or JavaScript attachments and exploit kit traffic triggered by casual web browsing.

Palo Alto Unit 42 · Aug 17, 2026Ransomware in the wild1

The MAL Simulator: Cyber Operations Simulation based on Attack & Defense Graphs

MAL Simulator grounds attack-defense graph simulations in a CRATE-emulated network, training RL attacker and defender agents where attackers outperform search methods.

The MAL Simulator is a cyber operations simulator built on the Meta Attack Language (MAL), enabling decision-driven attack and defense simulations adaptable to new domains without modifying source code. Case studies trained defensive and offensive agents, grounded in data collected from an emulated network implemented in the CRATE cyber range. The trained attacker policy reached designated targets more efficiently than compared search methods, and the trained defender induced lower costs than a naive heuristic under noisy alerts, though defender performance dropped significantly against an RL attacker.

arXiv cs.CR · 1d agoResearch

Mole Ransomware: How One Malicious Spam Campaign Quickly Increased Complexity and Changed Tactics

Unit 42 tracks the new Mole ransomware (CryptoMix family) spread via USPS-themed malspam, with tactics escalating to JavaScript downloaders dropping multiple malware families.

On April 11, 2017, a malspam campaign began distributing Mole ransomware, a CryptoMix-family strain, through USPS-themed emails linking to fake Microsoft Word Online sites offering a bogus Office plugin. By April 13 the campaign added Nemucod JavaScript downloaders installing Mole alongside Kovter and Miuref, and by April 18 it switched to the KINS banking Trojan before moving to speeding-ticket themes and a fake parking services website. Unit 42 notes the rapid tactic changes are likely intended to evade detection, and CryptoMix variants like Mole are typically repackaged within weeks.

Palo Alto Unit 42 · Aug 17, 2026Ransomware in the wild

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.

Security Affairs · 9d agoMalware1

Researchers Uncover 10,000+ Malware Loaders Behind YouTube and SEO Poisoning Campaign

Unit 42 uncovers CL-CRI-1171, a two-year pay-per-install campaign distributing 10,000+ OfferLoader samples via YouTube and SEO poisoning.

Palo Alto Networks Unit 42 tracked a campaign as CL-CRI-1171, an infection-as-a-service platform operating for at least two years. It used 11 YouTube gaming channels with hundreds of thousands of subscribers and SEO-poisoned download pages for trojanized WinDirStat and Bluetooth driver installers to distribute OfferLoader, a disposable loader embedded in Inno Setup installers. Payloads delivered included Insomnia RAT (Node.js and Python backdoors), ARKTunnel (a WebSocket-based RAT using LSB steganography), and Docro Hijacker (Chrome browser hijacker), with later infections delivering GCleaner and Socks5Systemz. Over 200 rotating domains across .xyz, .cfd, .space, and .info TLDs were used, with gating filters that served broken links or decoy pages to scanners and researchers.

GBHackers · 4d agoMalware in the wild2

KREMLIN Banking Malware Infects Over 1,500 Systems With Malicious Chrome Extension

Elastic tracks KREMLIN banking malware that used fake Brazilian bank JavaScript lures to deploy malicious Chrome and Edge extensions on 1,515 systems.

Elastic researchers tracked the KREMLIN banking malware operation across seven campaigns over 15 months, infecting 1,515 systems, 98.75% of them in Brazil. Portuguese-language lures posing as bank records and invoices deploy a hostile 'AVSync' extension into Chrome and Edge profiles that harvests passwords, session cookies, keystrokes and screenshots. Loaders check for sandboxes, create scheduled tasks and fetch fresh infrastructure from an Ethereum smart contract; a network canary takeover temporarily disrupted infections.

Cyber Security News · 3h agoMalware in the wild

The hidden work of modernizing Malwarebytes

Malwarebytes details its migration of Windows product managed components to .NET 10, citing security, supportability, diagnostics, and performance benefits.

Malwarebytes says it migrated the managed portions of Malwarebytes for Windows to .NET 10 while leaving native drivers and the detection engine untouched. The vendor cites a supported runtime, safer defaults, stronger cryptography, better diagnostics, and JIT/GC performance improvements as benefits. The migration also deprecated Windows 7 support, and the company applies staged rollouts and automated validation because its code runs with elevated privileges on millions of endpoints. No vulnerabilities or incidents are described.

Malwarebytes Labs · 11d agoIndustry1

Google Doc Sidebar Sends Mac and Windows Users Down Different Paths to Malware

Huntress analysts trace one X direct message into separate Mac and Windows malware chains delivering AMOS infostealer and NetSupport Manager RAT.

Huntress SOC analysts dissected a malware campaign distributed via an X direct message styled as a Google Docs sidebar. macOS users were routed to the AMOS infostealer, while Windows users received NetSupport Manager remote access malware. The write-up details how a single message branched into two distinct delivery paths per operating system.

Huntress · 4d agoMalware in the wild 4 sources

FrostyGoop’s Zoom-In: A Closer Look into the Malware Artifacts, Behaviors and Network Communications

Unit 42 dissects FrostyGoop OT malware, which sent Modbus TCP commands to disrupt heating for 600+ apartment buildings in Ukraine.

Palo Alto Unit 42 analyzed new FrostyGoop/BUSTLEBERM samples, the ninth known ICS-centric malware, first used against a Ukrainian municipal energy company by sending Modbus TCP commands to ENCO control devices. The attack caused a two-day heating outage affecting over 600 apartment buildings during sub-zero temperatures. The Go-compiled malware accepts Modbus register operations and timing parameters via command-line arguments or a JSON configuration file, uses an obscure open-source Modbus library, and checks the Windows BeingDebugged flag to evade debuggers. Unit 42 telemetry recorded over 1 million Modbus TCP devices exposed to the internet between September and October 2024.

Palo Alto Unit 42 · 27d agoMalware in the wild

KREMLIN Banking Malware Hijacks Chrome and Edge to Steal Credentials and Session Tokens

Elastic Security Labs details KREMLIN, Brazilian banking malware using malicious Chrome/Edge extensions and Ethereum smart contracts to steal credentials and session tokens.

Elastic Security Labs documents KREMLIN (tracked as REF9334), a Brazilian banking malware toolkit active since at least May 2025 that impersonates a dozen Brazilian banks. It uses multi-stage JavaScript loaders, a C++ installer that DLL-sideloads via a legitimate SentinelOne binary, and a malicious Chrome/Edge extension named 'AVSync System Inc.' Ethereum smart contracts act as dead-drop resolvers for C2 endpoints, a shift that occurred May 19, 2026, making infrastructure hard to disrupt. The extension harvests cookies, sessionStorage/localStorage, browsing history, screenshots, and full page HTML via WebSocket plus CSS-disguised polling endpoints. The group has run seven distinct campaigns and also distributes Pulsar RAT and Remcos RAT.

The Hacker Newsupdated · 6h agofirst · 16h agoMalware in the wild 2 sources

Hackers Use Fake Claude and ChatGPT Installers to Infect Mac Users With Password-Stealing Malware

Attackers distribute MacSync macOS infostealer via fake Claude and ChatGPT installers and sponsored search ads, stealing passwords, cookies, keys, and wallets.

SEQRITE reports a malware-as-a-service campaign pushing MacSync, a macOS password stealer, through sponsored search results and fake Claude and ChatGPT download pages. ClickFix-style prompts trick users into pasting a Terminal command that launches a stager, which loads an in-memory AppleScript to harvest credentials. The malware collects browser vaults, Keychain data, SSH keys, session cookies, messaging sessions, and cryptocurrency wallets, then persists via renamed LaunchAgents and can request screen-recording permissions.

Cyber Security News · 6d agoMalware in the wild 2 sources

Almost Half of Malware Samples Communicate Direct to IP

Unit 42 analysis of 4 million malware reports finds 45% of C2-active samples connect directly to hard-coded IPs, bypassing DNS defenses.

Palo Alto Unit 42 analyzed over 4 million Advanced WildFire dynamic analysis reports and found that 45.32% of malware samples with C2 activity made at least one direct-to-IP connection, accounting for 23.17% of all C2 connection attempts. The firm proposes zero trust IP (ZT-IP), an enforcement approach that verifies whether outbound destinations were ever sanctioned by a DNS response. ZT-IP analysis surfaced Phorpiex ransomware droppers fetching payloads directly from C2 IPs, a persistent data exfiltration campaign using an obfuscated \GET protocol, and Mozi P2P botnet payloads delivered to IoT devices without DNS. Only 1% of benign samples connected directly to untrusted IP addresses.

Palo Alto Unit 42 · 29d agoResearch

C2Looper: A New Backdoor Likely Tied To Ransomware With GitHub C2

Zscaler ThreatLabz identified C2Looper, a new Rust-based backdoor likely tied to ransomware actors and delivered via ClickFix chains, using GitHub for C2.

In July 2026, Zscaler ThreatLabz identified C2Looper, a new Rust-based backdoor family. The malware supports arbitrary command execution, reconnaissance, and deployment of second-stage payloads, and uses GitHub as its command-and-control channel. ThreatLabz assesses with low-to-medium confidence that it is delivered through multi-stage ClickFix infection chains and is likely leveraged by a ransomware-related threat actor. The analysis covers multiple C2Looper variants, their network protocols, and capabilities.

Zscaler ThreatLabz · 29d agoMalware in the wild1

BraZetsu Malware Turns Compromised Windows Hosts Into Criminal Marketplace Inventory

Group-IB details BraZetsu, a modular Python Windows malware that monetizes compromised-host access through the Infected Marketplace for initial access brokers.

Group-IB attributes BraZetsu to the Exilware threat actor, believed to be native Portuguese speakers targeting Iberian and Latin American e-commerce, financial, industrial, and law enforcement victims. The framework, first observed in early May 2026, uses generative AI for data triage and target prioritization, steals browser histories and digital certificates, and hunts Brazilian CNAB financial remittance files. Access to compromised hosts is sold on the Infected Marketplace from roughly $5.80, letting buyers remotely deploy secondary payloads over WebSocket-linked infrastructure. Some samples evaded detection on VirusTotal; delivery likely uses VBS loaders from a domain also used to distribute the Ousaban banking trojan.

The Hacker News · 12d agoMalware in the wild

Why Is SHAP Not a Reliable Standalone Explanation Framework for Malware Detection?

arXiv paper shows SHAP gives unreliable standalone explanations for malware detection, with attribution dilution and sign reversal in dependent PE feature spaces.

The paper argues SHAP's formal guarantees are insufficient for reliable malware interpretation because the explained feature-coalition game is fixed only by analyst choices, not by malware behavior in the data. In static Portable Executable feature spaces, dependent feature groups cause conditional SHAP to dilute credit by a factor of 1/m across redundant features, attribute importance to features the model never uses, and even reverse attribution signs; interventional SHAP queries off-manifold coalitions no real executable exhibits. Experiments on EMBER-2018, EMBER-2024, and BODMAS with fixed LightGBM and XGBoost detectors confirm these effects. The authors position SHAP as a limited diagnostic requiring explicit data-distribution statements and domain validation, not a standalone explanation framework.

arXiv cs.CR · 12d agoResearch1

Go-Based macOS Malware Steals Crypto and Secrets

Security researchers detected Go-based macOS malware stealing cryptocurrency, passwords, and other secrets from infected systems.

A Go-based malware variant targeting macOS has been detected in active use. The malware steals cryptocurrency, passwords, and other sensitive secrets from infected Macs.

Infosecurity Magazine · Aug 10, 2026Malware in the wild

Tracking Elirks Variants in Japan: Similarities to Previous Attacks

Unit 42 links new Elirks backdoor variants attacking Japanese organizations to 2012 Taiwan attacks, delivered via spear-phishing PDFs exploiting Adobe Flash CVE-2011-0611.

Unit 42 analyzed new Elirks backdoor variants found in an attack on a Japanese business, noting strong similarities to 2012 attacks on Taiwanese ministries. The backdoor retrieves its C2 address from attacker-created accounts on Japanese blog and SNS services. Recent deliveries used an airline e-ticket lure named "E-TKT" with a PDF exploiting Adobe Flash CVE-2011-0611. Shared infrastructure and tactics with the Scarlet Mimic campaign suggest possible ongoing cyber espionage across East Asia.

Palo Alto Unit 42 · 29d agoThreat actor in the wildCVE-2011-0611

SEMA-GUARD: Semantic and Graph-Based Vulnerability Detection in Assembly Code

SEMA-GUARD uses semantic analysis and graph neural networks to detect vulnerabilities in assembly code, achieving 85.1% accuracy on a Juliet-derived benchmark.

SEMA-GUARD is a framework that detects vulnerabilities in compiled programs when source code is unavailable, targeting malware, firmware, and embedded systems analysis. It enriches control flow graphs with low-level execution semantics including stack manipulations, memory accesses, and data flow. Evaluated on a Juliet Test Suite set compiled to assembly and split into function-level chunks, it achieves 85.1% accuracy and an F1 score of 0.801, outperforming purely statistical or structural approaches.

arXiv cs.CR · 21h agoResearch1

Campaign Evolution: pseudo

Unit 42 traces the pseudo-Darkleech campaign's 2016 shift from Angler to Neutrino to Rig exploit kits and rotating ransomware payloads.

Unit 42 documents how the pseudo-Darkleech exploit kit campaign evolved through 2016, switching from Angler EK to Neutrino EK in June and to Rig EK in September after Neutrino ceased operations. Payloads rotated from TeslaCrypt to CryptXXX, CrypMIC, and finally Cerber ransomware by October 2016. Injected script on compromised websites changed from 12,000-18,000 character obfuscated blocks to short, unobfuscated hidden iframes starting July 1, 2016.

Palo Alto Unit 42 · Aug 17, 2026Threat actor in the wild