Full Report
Security researchers at Apiiro have released two free, open-source tools designed to detect and block malicious code before they are added to software projects to curb supply chain attacks. [...]
Analysis Summary
# Tool/Technique: Apiiro Malicious Code Detection Ruleset / PRevent
## Overview
Apiiro has released a free scanner (ruleset) and a related tool, PRevent, focused on detecting malicious code merges and suspicious code patterns within software repositories, specifically targeting package repositories like PyPI and npm, and real-time analysis of Pull Requests (PRs).
## Technical Details
- Type: Tool / Detection Framework (Ruleset and CI/CD scanner)
- Platform: Applicable to codebases utilizing CI/CD pipelines, specifically scanning npm and PyPI packages. The underlying scanning engine can be adapted for use with Semgrep or Opengrep.
- Capabilities: Static code analysis to identify "code anti-patterns" indicative of malware, real-time scanning of PRs, high accuracy in detecting malicious code in package metadata/code.
- First Seen: Not explicitly mentioned, but the news regarding the free release is recent.
## MITRE ATT&CK Mapping
Since this is a **defensive/detection tool**, the mappings relate to the phases of attack that it is designed to prevent:
- **TA0002 - Execution**
- T1059.005 - Command and Scripting Interpreter: Python (Detecting malicious code execution via `exec`/`eval`)
- **TA0005 - Defense Evasion**
- T1027 - Obfuscated Files or Information (Detecting obfuscation methods)
- **TA0010 - Exfiltration**
- T1041 - Exfiltration Over C2 Channel (Detecting code attempting to exfiltrate data)
- **TA0001 - Initial Access** (Specifically preventing supply chain access via compromised packages)
## Functionality
### Core Capabilities
- **Static Analysis:** Scans code without execution to maintain a safe analysis environment.
- **Anti-Pattern Detection:** Uses a ruleset based on suspicious behaviors common in malware but rare in legitimate code.
- **Package Scanning:** Specifically designed for scanning dependencies/packages from PyPI (94.3% accuracy) and npm (88.4% accuracy).
- **CI/CD Integration:** Designed to integrate into CI/CD pipelines for automated repository scanning.
### Advanced Features
- **PRevent Tool:** Specifically scans Pull Request (PR) events in real-time *before* code merges into the main branch (91.5% success rate in flagging malicious PRs).
- **Actionable Alerts:** PRevent can block merges or automatically add comments to PRs detailing detected risks.
- **Identified Anti-Patterns:** Detection focuses on:
1. Obfuscation techniques (encoding, nested transformations, runtime modifications).
2. Use of high-risk functions (`exec()`, `eval()`) allowing arbitrary code execution.
3. Code that downloads and executes remote payloads.
4. Methods used for sensitive data exfiltration.
## Indicators of Compromise
This tool *detects* IoCs; it does not generate IoCs itself in the context of an ongoing compromise. The focus is on the presence of malicious code patterns *prior* to deployment.
- File Hashes: N/A (Rule-based detection)
- File Names: N/A
- Registry Keys: N/A
- Network Indicators: N/A (The tool detects code *intended* to connect to C2, but does not list specific C2s.)
- Behavioral Indicators: Code exhibiting unusual compilation/execution methods, attempting remote downloads, or communicating with external servers.
## Associated Threat Actors
The article does not name specific threat actors using this tool; it describes a **defensive solution** designed to catch actors attempting supply chain attacks via package ecosystems.
## Detection Methods
The tool itself *is* the proposed detection mechanism.
- Signature-based detection: Based on predefined "code anti-patterns."
- Behavioral detection: Based on code features suggestive of evasion or execution abuse.
- YARA rules if available: The ruleset is available on GitHub, likely implemented using Semgrep/Opengrep syntax, not explicitly YARA, but serving a similar purpose for static pattern matching.
## Mitigation Strategies
Mitigation is achieved through the deployment and integration of the scanner/tool:
- **Prevention (Pre-Merge):** Utilizing PRevent to block malicious code from entering the repository via PRs before it reaches production.
- **Supply Chain Security:** Implementing static analysis scanning on imported npm and PyPI packages.
- **Pipeline Hardening:** Integrating the static analysis ruleset into CI/CD pipelines.
## Related Tools/Techniques
- **Semgrep/Opengrep:** The ruleset can be adapted to run using these general-purpose static analysis tools.
- **Static Application Security Testing (SAST):** The methodology aligns with general SAST scanning principles, though focused specifically on malware/supply chain risks rather than general vulnerabilities.
- **Limitations:** Cannot detect malware hidden in compiled binaries.