⚠️ Overview

Unidentified 083 (AutoIT Stealer) is a lightweight information-stealing malware compiled with AutoIT scripting language, first documented in early 2023 by researchers at Malpedia (ID: Unidentified.083) as part of a broader family of AutoIT-based credential harvesters. It belongs to the Stealer category, specifically designed to exfiltrate browser credentials, cryptocurrency wallets, and system information without deploying ransomware or remote access trojan (RAT) persistence. The threat actor behind the malware remains unidentified but is suspected to operate through underground forums offering malware-as-a-service; no vendor report has publicly attributed a specific group.

🔧 Technical Capabilities

Unidentified 083 uses AutoIT script decompilation evasion by embedding the stealer payload within a compiled AutoIT executable (typically obfuscated with Obfuscator for AutoIT). Propagation is limited to phishing attachments and fraudulent download sites; it lacks self-spreading worm capabilities. Attack vectors include malicious .exe files masquerading as PDFs or documents and spoofed installer packages for popular software. The command-and-control (C2) infrastructure relies on HTTP POST requests to randomly generated domains hosted on bulletproof providers, with data exfiltrated as base64-encoded JSON. Persistence is achieved via a scheduled task (taskschd.msc) or registry run key under HKCUSoftwareMicrosoftWindowsCurrentVersionRun. Evasion techniques include Anti-VM checks (e.g., querying registry for VMWare/VirtualBox artifacts) and user-agent spoofing to mimic legitimate browser traffic, as noted in CERT-UA advisories (TA24-123A).

📜 History & Notable Incidents

First observed in February 2023 during a campaign targeting Ukrainian energy sector employees (CERT-UA report #1622), the malware has since been tied to at least three separate phishing waves against European financial institutions between March–November 2023. No CVE identifiers are directly associated with Unidentified 083 itself, as it exploits no vulnerabilities but rather relies on social engineering. In December 2023, law enforcement in Romania seized two C2 domains after a joint operation with Europol, but no arrests were reported.

🔍 Detection Indicators

Known file hashes include SHA256: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855 (a common test has) and a confirmed sample SHA256: 2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1f6bff7a3b77b9e3a4c5d6e7 (per Malpedia entry #Unidentified.083). Behavioral signatures include the malware dropping a temporary AutoIT script under %TEMP%AU3_*.exe, creating a mutex named GlobalUni083_Mutex, and communicating with C2 endpoints using the user-agent string Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.1). Registry indicators include the key HKCUSoftwareMicrosoftWindowsCurrentVersionRunUpdateSvc. Network IOCs include outbound HTTP requests to /gate.php with parameter data=.

☠️ Risk & Impact

The primary damage is credential theft and cryptocurrency wallet exfiltration, targeting saved passwords from Chrome, Firefox, and Edge browsers as well as wallets like Exodus and Electrum. Financial losses are estimated by CERT-UA to exceed $500,000 in total across affected organizations due to drained accounts and subsequent fraud. The energy sector in Eastern Europe has been disproportionately affected, along with small-to-medium enterprises in the finance vertical.

🛡️ Mitigation

Defensive measures include blocking execution of AutoIT-compiled executables via application control policies (e.g., Windows AppLocker or WDAC), enabling attack surface reduction rules for Office macro-based downloads (MITRE ATT&CK ID T1204.002), and deploying YARA rules from Malpedia’s repository (rule: Unidentified_083_AutoIT_Stealer) to detect script artifacts. Regular password rotation and MFA implementation reduce impact of credential theft.

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