Full Report
2025-04-28 • Netresec • Erik Hjelmvik • win.njrat Open article on Malpedia
Analysis Summary
It appears the provided context is a very brief article description focusing on the analysis of njRAT traffic using NetworkMiner, rather than providing deep technical specifics about njRAT itself (hashes, extensive features, full MITRE mapping, etc.).
Therefore, the summary below will be constructed based on the standard knowledge associated with njRAT, supplemented by the information that the analysis specifically used NetworkMiner and focused on decoding its traffic.
# Tool/Technique: njRAT (Njoke Remote Access Trojan)
## Overview
njRAT (Njoke Remote Access Trojan) is a well-known Remote Access Trojan (RAT) primarily used by threat actors to gain persistent, covert control over compromised Windows hosts. The article specifically mentions the process of decoding njRAT network traffic using NetworkMiner.
## Technical Details
- Type: Malware family (RAT)
- Platform: Windows
- Capabilities: Remote control, file system access, webcam/microphone monitoring, keylogging, credential theft.
- First Seen: Circa 2012 (Initial variants); still actively used or re-emerging in newer forms.
## MITRE ATT&CK Mapping
*Note: Since the article doesn't provide explicit mappings, general mappings for a common RAT like njRAT are used.*
- TA0011 - Command and Control
- T1071 - Application Layer Protocol
- T1071.001 - Web Protocols
- TA0005 - Defense Evasion
- T1027 - Obfuscated Files or Information
- TA0003 - Persistence
- T1547 - Boot or Logon Autostart Execution
## Functionality
### Core Capabilities
- Establishing a persistent backdoor connection to a Command and Control (C2) server.
- Executing remote commands (shell access).
- Retrieving files from the victim machine.
- Monitoring user activity (keylogging, screen capture).
### Advanced Features
- Traffic obfuscation or encryption to evade simple network inspection (the article premise suggests analysis is required to decode this traffic).
- Plugin architecture allowing for modular expansion of capabilities.
## Indicators of Compromise
*Note: Specific IoCs are not provided in the context description. Standard place-holders are used.*
- File Hashes: N/A (Specific hashes depend on the variant analyzed)
- File Names: Typically disguised executables or DLLs.
- Registry Keys: Modifications to Run keys for persistence.
- Network Indicators: Connections to known C2 infrastructure utilized by njRAT operators. (e.g., pattern-based traffic analysis).
- Behavioral Indicators: Unexpected outbound TCP connections on non-standard ports or attempts to establish network listeners.
## Associated Threat Actors
njRAT is widely distributed and often used by various cybercrime groups, small-scale attackers, and hacktivist entities due to its relatively accessible nature compared to state-sponsored malware.
## Detection Methods
- Signature-based detection: Known hashes or specific string signatures within the malware binary.
- Behavioral detection: Monitoring for unusual process injection, unauthorized outbound network connections, and unauthorized modifications to system startup locations.
- YARA rules: Rules targeting known njRAT binary structures or embedded strings.
## Mitigation Strategies
- Application whitelisting to prevent unauthorized execution of the RAT payload.
- Network segmentation and strict egress filtering to limit beaconing success.
- Regular patching of exploited vulnerabilities used in initial access.
- Use of EDR/XDR solutions capable of detecting RAT-like process behavior.
## Related Tools/Techniques
- Other common RATs like Gh0st RAT, DarkComet, or custom backdoors.
- Tools used for traffic decoding/analysis like: **NetworkMiner** (as mentioned in the context).