CVE-2020-7384: Rapid7 Metasploit msfvenom RCE Vulnerability

CVE-2020-7384 Overview

Rapid7's Metasploit msfvenom framework handles APK files in a way that allows for a malicious user to craft and publish a file that would execute arbitrary commands on a victim's machine. This command injection vulnerability (CWE-77) affects the APK template processing functionality within msfvenom, a popular payload generation tool used extensively by penetration testers and security researchers.

Critical Impact

Attackers can craft malicious APK template files that execute arbitrary system commands when processed by msfvenom, potentially compromising the security researcher's own system.

Affected Products

• Rapid7 Metasploit Framework (msfvenom component)
• Metasploit Framework versions prior to the security patch
• Systems using msfvenom with untrusted APK templates

Discovery Timeline

• 2020-10-29 - CVE-2020-7384 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2020-7384

Vulnerability Analysis

This vulnerability represents a command injection flaw in how msfvenom processes APK template files. When users supply a custom APK file as a template for payload generation, the application fails to properly sanitize certain fields within the APK structure before passing them to system commands. This creates an opportunity for attackers to embed malicious commands within specially crafted APK files.

The irony of this vulnerability is significant: a tool designed for security testing can itself become the attack vector. Security researchers downloading APK templates from untrusted sources could unknowingly execute malicious commands on their own systems when generating payloads.

Root Cause

The root cause is improper input validation (CWE-77: Command Injection) in the APK template handling code. When msfvenom processes an APK file, it extracts and uses certain metadata fields in shell commands without proper sanitization. An attacker can inject shell metacharacters and commands into these fields, which are then executed with the privileges of the user running msfvenom.

Attack Vector

The attack requires local access and user interaction. An attacker must:

1. Create a malicious APK file containing command injection payloads in specific metadata fields
2. Distribute this file through channels where security researchers might obtain APK templates (forums, repositories, social engineering)
3. Wait for a victim to use the malicious APK as a template with msfvenom

When the victim runs msfvenom with the -x flag to specify the malicious APK as a template, the injected commands execute on the victim's system. This could lead to complete system compromise, data exfiltration, or further lateral movement within the victim's network.

The vulnerability mechanism involves shell metacharacter injection through APK metadata fields that are processed by msfvenom during payload generation. For detailed technical analysis and exploitation techniques, refer to the Packet Storm security advisory and the Metasploit Framework 6.0.11 Command Injection advisory.

Detection Methods for CVE-2020-7384

Indicators of Compromise

• Unexpected child processes spawned by msfvenom or Ruby interpreter
• Suspicious network connections originating from the system running msfvenom
• Anomalous file system modifications during payload generation operations
• Shell commands in msfvenom logs that don't match expected behavior

Detection Strategies

• Monitor process trees for msfvenom executions that spawn unexpected shell commands
• Implement file integrity monitoring on APK template directories
• Use behavioral analysis to detect command injection patterns in security tool usage
• Review APK files before use with static analysis tools to identify embedded commands

Monitoring Recommendations

• Enable verbose logging for Metasploit Framework operations
• Monitor for unusual system calls during msfvenom payload generation
• Track network connections initiated during APK processing
• Implement application whitelisting to detect unexpected command execution

How to Mitigate CVE-2020-7384

Immediate Actions Required

• Update Metasploit Framework to the latest patched version immediately
• Avoid using APK templates from untrusted or unverified sources
• Review any custom APK templates currently in use for suspicious content
• Run msfvenom in isolated or sandboxed environments when using external templates

Patch Information

Rapid7 has addressed this vulnerability through a security update to the Metasploit Framework. The fix is available via the official GitHub pull request #14288. Users should update their Metasploit installation using msfupdate or by pulling the latest version from the GitHub repository.

Workarounds

• Only use APK templates from trusted, verified sources or generate them internally
• Run msfvenom in a containerized or virtual environment to limit blast radius
• Manually inspect APK files before using them as templates
• Implement network segmentation for systems running penetration testing tools

# Update Metasploit Framework to latest version
msfupdate

# Alternatively, update via Git
cd /opt/metasploit-framework
git pull origin master
bundle install