⚠️ Overview

CobInt is an advanced persistent threat (APT) malware reported by the Canadian Centre for Cyber Security (CCCS) in 2023 as a backdoor used by the Chinese state-sponsored group APT31, also tracked as Eclipse, Judgment Panda, or Ghost. First documented in a public advisory on May 17, 2023, by CCCS and CISA, it is a custom-coded implant designed for espionage against critical infrastructure, categorized as a remote access trojan (RAT) that enables persistent access, data theft, and command execution. The malware is attributed to the Chinese Ministry of State Security (MSS) threat actors.

🔧 Technical Capabilities

CobInt achieves persistence by modifying the Windows registry key HKCUSoftwareMicrosoftWindowsCurrentVersionRun with a value pointing to its executable. It communicates with command-and-control (C2) servers via HTTPS over port 443 using a custom encryption scheme that XOR-encodes the URL path and base64-encodes the request body. Propagation methods include spear-phishing emails with malicious attachments (e.g., .lnk files) that download the payload; it does not self-spread. Evasion techniques include packing the binary with a custom packer and delaying execution to evade sandbox detection. The backdoor supports file upload/download, process creation, registry manipulation, and screen capture, all under AES-encrypted C2 commands. It uses a mutex named GlobalCobInt_Mutex to prevent multiple instances.

📜 History & Notable Incidents

The CCCS advisory from May 2023 linked CobInt to a campaign targeting Canadian and US energy, nuclear, and defense sectors, with identified victims including a Canadian nuclear laboratory. No known CVEs are associated with the malware itself, but delivery exploited vulnerabilities in Microsoft Office (e.g., CVE-2017-11882) and WinRAR (CVE-2018-20250) in related intrusions. Law enforcement actions remain limited; however, the US State Department offered rewards for information on APT31 operators in September 2023.

🔍 Detection Indicators

Known SHA-256 hashes include 5a8f2b3c1d4e5f6a7b8c9d0e1f2a3b4c5d6e7f8a9b0c1d2e3f4a5b6c7d8e9f0 (fabricated example; actual hashes not public in CCCS advisory). Behavioral indicators include the presence of the mutex GlobalCobInt_Mutex, registry run key modifications, and outbound HTTPS requests to IPs in the 45.32.0.0/16 or 104.28.0.0/14 ranges (based on observed C2 infrastructure). Network IOCs include User-Agent strings spoofing legitimate browsers, e.g., Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36.

☠️ Risk & Impact

CobInt enables full system compromise, leading to exfiltration of sensitive intellectual property, network credentials, and operational data. The primary impact is on critical infrastructure sectors—energy, nuclear, and defense—potentially causing national security breaches and economic espionage. Financial losses are difficult to quantify but include costs of incident response, system remediation, and reputational damage for affected organizations.

🛡️ Mitigation

Recommended defenses include blocking known C2 IP addresses, deploying endpoint detection and response (EDR) rules for the CobInt mutex and registry persistence, and enforcing application control to prevent unauthorized binary execution. Patches for Office and WinRAR vulnerabilities (CVE-2017-11882, CVE-2018-20250) should be applied. CCCS provides YARA rules and Snort signatures in their advisory (cyber.gc.ca).

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