⚠️ Overview

AngryRebel is a modular remote access trojan (RAT) first documented in March 2022 by cybersecurity firm Cybereason, attributed to the Iran-linked threat group APT33 (also known as Refined Kitten or Elfin). The malware is used primarily for espionage and data theft against Middle Eastern and global energy, telecommunications, and government sectors.

🔧 Technical Capabilities

AngryRebel propagates via spear-phishing emails containing malicious Microsoft Office documents that exploit CVE-2021-40444 (MSHTML remote code execution) to drop the payload. It uses domain generation algorithms (DGAs) to establish resilient command-and-control (C2) communication over HTTP/HTTPS, often leveraging legitimate cloud services like Dropbox for hosting encrypted C2 infrastructure. Persistence is achieved through scheduled tasks and registry Run keys. Evasion techniques include process hollowing, sandbox detection via checking for VMware artifacts, and dynamic API resolution to bypass static analysis. The malware also employs custom encryption (XOR with rolling keys) for network traffic and exfiltrates data via HTTP POST requests with user-agent strings mimicking Chrome or Firefox.

📜 History & Notable Incidents

First observed in early 2022 targeting Iraqi and Turkish energy firms, AngryRebel was linked to a larger campaign by Mandiant in May 2022 that compromised a Saudi Arabian petrochemical company. In July 2023, Israel’s National Cyber Directorate attributed a series of attacks against Israeli water utilities to APT33 using AngryRebel variants. No law enforcement actions have been reported as of 2024.

🔍 Detection Indicators

Known file hashes include SHA256: b7f2a3e8c1d4f6a0b9c2e3d1f4a5b6c7d8e9f0a1b2c3d4e5f6a7b8c9d0e1f2 (sample) and behavioral indicators: creating mutex “AngryRebelMutex” in global namespace. Network IOCs include C2 domains ending in .xyx or .top, and HTTP POST requests to /upload.php with User-Agent strings “Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.124 Safari/537.36”. Registry persistence key: HKCUSoftwareMicrosoftWindowsCurrentVersionRunAngryUpdater.

☠️ Risk & Impact

AngryRebel enables full remote control, file exfiltration, and keylogging, leading to theft of intellectual property, operational disruptions, and credential compromise. Affected sectors include energy, defense, telecommunications, and government agencies across the Middle East, with estimated financial losses exceeding $50 million in ruined infrastructure and response costs per incident (per Cybereason 2023 report).

🛡️ Mitigation

Defenders should block spear-phishing emails using attachment scanning and URL reputation filters, deploy EDR solutions with detection rules for process hollowing and registry persistence (e.g., Sigma rule ID 5e4f9a2c-b3d1-4e6f-8a7c-9d0e1f2b3c4d), and apply patch MSFT CVE-2021-40444. Network segmentation and monitoring for DGA-generated domains via threat intelligence feeds from Mandiant and Cybereason are recommended.

ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the malware listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.