AI Security Analysis: nl

Analysis generated: 2025-12-11T21:01:29+13:00
Model: gemini-3-pro-preview

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Quick Facts

Property	Value
UUID	40464b8c-3856-5788-86b1-b7e83f61e428
Type	firefox
Version
Users	258
Risk Score	100.0/100 (CRITICAL)
Malware Detected	⚠️ Yes
Secrets Exposed	✅ No
Critical Vulns	✅ No

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AI Analysis

Executive Summary

CRITICAL RISK - DO NOT INSTALL / IMMEDIATE REMOVAL REQUIRED

The Firefox extension "nl" presents an immediate and severe security threat. The analysis indicates a high probability that this extension functions as a malware dropper or a compromised software component. It exhibits behaviors consistent with malicious software, including the ability to execute system commands, download external files, and establish persistence on the host machine. With a generic name, an unverified publisher, and a perfect risk score of 100/100, this extension should be considered malicious until proven otherwise.

Threat Assessment

The security posture of this extension is critically compromised. The analysis reveals a pattern of behavior typically associated with "supply chain attacks" or "droppers"—malware designed to install other malicious payloads.

• Remote Code Execution (RCE) Potential: The presence of postinstall_system_command and postinstall_file_manipulation signatures suggests the extension attempts to break out of the standard browser sandbox to execute commands directly on the host operating system.
• Malware Dropper Behavior: The combination of postinstall_file_download and postinstall_file_manipulation indicates the extension likely downloads external binaries or scripts and executes them.
• Evasion and Persistence: The extension utilizes obfuscation (postinstall_obfuscation) to hide its code logic and attempts to modify the system to ensure it restarts automatically (postinstall_persistence_mechanism).
• Anomalous IOC Volume: The extension contains 4,339 Indicators of Compromise (IOCs). This is highly abnormal for a standard extension. It suggests the extension may contain a hardcoded list of Command & Control (C2) servers, a target list for botnet activities, or a massive phishing blocklist used as a decoy.

Risk Justification

Risk Score: 100.0/100 (CRITICAL)

This score is fully justified and potentially conservative.

1. Severity of Capabilities: The findings are not merely privacy violations; they represent a total compromise of the host system (file manipulation, system commands).
2. Intent: The combination of obfuscation, persistence mechanisms, and crypto operations strongly implies malicious intent rather than accidental misconfiguration.
3. Lack of Trust: The developer is unverified, the user count is negligible (258), and the name "nl" is generic, which is a common tactic to fly under the radar.

Key Findings

• System Command Execution (postinstall_system_command): The extension contains code patterns associated with executing shell or system-level commands, posing a direct threat to the host OS.
• Persistence Mechanisms (postinstall_persistence_mechanism): Evidence suggests the extension attempts to modify system files (like registry keys or startup folders) to ensure it runs even after the browser is closed or the system is rebooted.
• Obfuscated Code (postinstall_obfuscation): The code has been intentionally obscured, likely to bypass automated scanners and hinder manual review.
• File System Manipulation (postinstall_file_manipulation): The extension has the capability to create, modify, or delete files on the user's machine.
• Credential Targeting (credential_env_files): A specific signature match indicates the extension may be scanning for or targeting environment files (.env), which typically contain API keys, database passwords, and other secrets.

Recommendations

1. Immediate Removal: Uninstall the extension immediately from all affected browsers.
2. Incident Response: Treat any machine that had this extension installed as compromised. Initiate standard incident response procedures.
3. Credential Rotation: Rotate all credentials, specifically those stored in environment variables, browser password managers, or cached sessions, as the credential_env_files finding suggests these were targeted.
4. Full System Scan: Run a full endpoint protection (EDR/Antivirus) scan to detect any secondary payloads that may have been downloaded (postinstall_file_download).
5. Network Blocking: If the 4,339 IOCs can be extracted, block these domains/IPs at the firewall level immediately.

Mitigation Strategies

There are no safe mitigation strategies for using this extension.

Due to the presence of Remote Code Execution (RCE) and persistence signatures, the risk cannot be mitigated via configuration or behavioral changes. The extension must be blocked at the organizational level via group policy (GPO) or enterprise browser management tools.

Confidence Assessment

Confidence Level: 80%

• Supporting Factors: The sheer volume of distinct, high-severity YARA matches (269 HIGH findings) targeting different stages of the kill chain (download, execute, persist) provides strong evidence of malicious functionality. The unverified publisher status reinforces this.
• Limiting Factors: Without manual code review, we cannot confirm if the postinstall_ signatures are part of the extension's active code or if the developer accidentally included a compromised npm package (a supply chain attack against the developer themselves) without stripping the development artifacts. However, from the end-user perspective, the risk is identical: the malicious code is present.

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Disclaimer

This analysis was generated by an AI model and should be reviewed by security professionals. The findings are based on automated security scanning and may include false positives. Always verify critical findings manually before taking action.