Threats Tagged 'infostealer'

A previously undocumented Windows loader designated as OXLOADER delivers the CASTLESTEALER infostealer through malicious Google Ads campaigns, achieving remarkably low detection rates. The loader employs multiple obfuscation layers including control-flow flattening, opaque predicates, and mixed Boolean-Arithmetic techniques, along with self-modifying decryption stubs and abuse of the Windows .reloc section for shellcode staging. Distribution occurs via malvertising impersonating Node.js installations, redirecting victims through intermediary domains to Storj-hosted batch scripts. The loader implements five anti-VM and language checks, including CIS-region and Russian-language exclusions, suggesting a financially motivated Russian-speaking threat actor. OXLOADER uses DonutLoader to deliver the .NET-based CASTLESTEALER payload in memory, evading traditional detection mechanisms through deliberate engineering choices.

MediumMalwareUnited States#oxloader#donutloader#reloc section abuse

This analysis covers infostealer distribution trends observed during May 2026, based on automated collection systems and diagnostic logs. Distribution occurred primarily through illegal software disguised as cracks and keygens, as well as email campaigns. ACRStealer, Remus, and LummaC2 were most prevalent, with distribution via domains including Mediafire and AWS S3 buckets. Microsoft was the most impersonated company, followed by Auslogics and NVIDIA. EXE files represented 78.9% of execution types, while DLL side-loading accounted for 21.1%. macOS environments saw ClickFix techniques and malicious Bash scripts, with 142 scripts and 12 C2 domains identified. Email campaigns distributed AgentTesla and DarkCloud. Remus showed significant growth, comprising 36% of distributions. LummaC2 remained the most prevalent overall variant.

More than 140 Mastra npm packages were compromised through a supply chain attack that injected a typosquatted dependency called easy-day-js. A single npm account published malicious versions within a short timeframe, affecting packages including @mastra/core with over 918K weekly downloads. The attack executes during npm install via a postinstall hook, deploying a two-stage payload. The first stage disables TLS validation and downloads a second-stage implant that installs cross-platform persistence on Windows, macOS, and Linux. This implant functions as a command-and-control client that steals cryptocurrency wallet inventories from 166+ browser extensions, harvests browser history, and can execute arbitrary code sent by operators. The malicious code executes before developers import packages, compromising systems during installation.

Since late 2025, cybercriminals have been exploiting Wallpaper Engine, a popular live wallpaper application on Steam, to distribute malware through Steam Workshop. Attackers target primarily Chinese and Russian gamers by embedding malicious code within application wallpapers shared on the platform. These compromised wallpapers deliver various malware types including infostealers, backdoors, crypto miners, and ransomware. One analyzed sample dropped DarkKomet backdoor while hijacking Steam sessions to steal account credentials. The malware modifies system libraries to locate Steam installations and exfiltrate data to attacker-controlled servers. Compromised accounts are then used to upload additional malicious wallpapers. The diverse malware families suggest multiple independent hacking groups are exploiting this distribution method. Infected wallpapers received thousands of downloads before removal, with 89% of infections occurring in China.

MediumMalwareBritish Indian Ocean TerritoryCanadaChina+5#account hijacking#vidar#wallpaper engine

Threat actors are leveraging TikTok and Instagram Reels to distribute the Vidar infostealer through fake software tutorials. Two distinct campaigns use short-form videos disguised as tutorials for unlocking premium software like Spotify. The first campaign uses accounts mimicking official Windows profiles with AI-voiced clips instructing users to run PowerShell commands that download Vidar from lookalike domains. One video achieved over 100,000 views. The second campaign uses ordinary accounts posting music-backed clips that bait users in comments to receive malicious links via direct message. These campaigns exploit platform recommendation algorithms by encouraging saves and shares. Vidar is sold as a service for $300 lifetime license and harvests credentials, financial data and authentication tokens.

Threat actors are exploiting short-form video platforms like TikTok and Instagram Reels to conduct social engineering attacks. Two distinct campaign methods have been identified: professional-looking fake tutorials with AI-generated voiceovers promising free premium software, and casual videos showcasing premium features to generate engagement through comments. Both approaches direct victims to malicious websites hosting infostealer malware, particularly Vidarstealer. The campaigns leverage platform algorithms through high engagement rates including saves, shares, and comments. Attackers use multiple accounts with Windows-themed branding and manipulate PowerShell commands to download malicious executables. These techniques are difficult to counter as creators can delete warning comments and platform reporting mechanisms prove ineffective. The attacks target non-technical users seeking free access to premium services like Spotify, Microsoft Office, and other software, making social media feeds an emerging p...

This analysis examines Gamaredon's (UAC-0010, Armagedon) advanced espionage operations targeting Ukrainian government, military, and critical infrastructure. The FSB-operated group deploys GammaSteel, a sophisticated stealer operating almost entirely from memory using Windows DPAPI encryption and storing 71 distinct payload functions in the HKCU\Printers registry key. The malware employs three concurrent data acquisition mechanisms: timed drive scans, USB monitoring for air-gapped systems, and real-time file surveillance. Exfiltration occurs via legitimate S3-compatible cloud storage (Tebi.io) with fallback to operator-controlled servers. The infection chain extensively uses VBScript for evasion, Dead Drop Resolvers on platforms like Telegram and Mastodon for C2 configuration, and includes bidirectional backdoor capabilities enabling arbitrary remote code execution. Infrastructure demonstrates high automation with servers rotated approximately every 24 hours.

MediumMalwareUkraine#vbscript#gammaworm#cyberespionage

Threat actors exploited the EtherHiding technique to store ClearFake payload routing instructions within smart contracts on the BNB Smart Chain testnet, creating an immutable command-and-control infrastructure that cannot be taken down. The attack began with injected JavaScript on a compromised Swiss website that queried blockchain contracts to deliver malicious payloads. Victims passing anti-analysis checks were fingerprinted by operating system and routed to platform-specific ClickFix social engineering overlays. The campaign simultaneously deployed SectopRAT, a .NET-based remote access trojan capable of browser session hijacking, and ACRStealer, a C++ infostealer targeting credentials and cryptocurrency wallets. An on-chain execution tracker confirmed each compromise in real time. Four smart contracts shared a single deployer wallet, with the oldest deployed nearly a year before analysis, indicating a long-running, actively maintained operation.

MediumMalwareSwitzerland#infostealer#blockchain c&c#clickfix