CVE-2020-5419: Broadcom RabbitMQ Server RCE Vulnerability

CVE-2020-5419 Overview

CVE-2020-5419 is a Windows-specific binary planting security vulnerability affecting RabbitMQ versions 3.8.x prior to 3.8.7. This vulnerability allows an attacker with write privileges to the RabbitMQ installation directory and local access on Windows to carry out a local binary hijacking (planting) attack and execute arbitrary code. Binary planting attacks exploit the Windows DLL search order mechanism to load malicious binaries instead of legitimate ones.

Critical Impact

An attacker with local access and write privileges to the RabbitMQ installation directory on Windows systems can achieve arbitrary code execution through binary hijacking, potentially compromising the entire messaging infrastructure.

Affected Products

• Broadcom RabbitMQ Server versions 3.8.x prior to 3.8.7
• Pivotal Software RabbitMQ versions 3.8.x prior to 3.8.7

Discovery Timeline

• August 31, 2020 - CVE-2020-5419 published to NVD
• April 2, 2025 - Last updated in NVD database

Technical Details for CVE-2020-5419

Vulnerability Analysis

This vulnerability is classified under CWE-427 (Uncontrolled Search Path Element), which describes a class of vulnerabilities where an application searches for critical resources using an externally-supplied search path that can point to resources outside of the intended control sphere. In the case of RabbitMQ on Windows, the application fails to properly secure the search path used when loading executable binaries or DLLs.

The attack requires local access to the target Windows system and write permissions to the RabbitMQ installation directory. This combination of prerequisites means that while exploitation is not trivial, once achieved, the impact is significant as it allows for complete code execution within the context of the RabbitMQ service.

Root Cause

The root cause of CVE-2020-5419 lies in inadequate path validation and insecure search path configuration within the RabbitMQ Windows installation. When RabbitMQ loads certain binaries or DLLs during operation, it does not properly restrict the search path, allowing an attacker who can write to the installation directory to place a malicious binary that will be loaded instead of or before the legitimate one.

This type of vulnerability typically occurs when:

• The application searches for DLLs in the current working directory or application directory before system directories
• Installation directory permissions are not properly restricted
• The application does not use absolute paths for loading critical binaries

Attack Vector

The attack vector for CVE-2020-5419 requires local access to the Windows system hosting RabbitMQ. An attacker must have write privileges to the RabbitMQ installation directory. The attack proceeds as follows:

1. The attacker gains local access to the target Windows machine running RabbitMQ
2. The attacker identifies the RabbitMQ installation directory and confirms write permissions
3. The attacker crafts a malicious binary with the same name as a legitimate binary that RabbitMQ loads during operation
4. The attacker places this malicious binary in the RabbitMQ installation directory
5. When RabbitMQ starts or performs certain operations, it loads the malicious binary instead of the legitimate one
6. The attacker's code executes with the privileges of the RabbitMQ service

The binary planting technique exploits the Windows DLL/executable search order to achieve code execution without modifying any legitimate RabbitMQ files. For detailed technical information, refer to the VMware Security Advisory.

Detection Methods for CVE-2020-5419

Indicators of Compromise

• Unexpected executable files or DLLs appearing in the RabbitMQ installation directory
• File modification timestamps on binaries that don't align with legitimate updates
• Suspicious process execution originating from the RabbitMQ installation path
• Unusual network connections or behavior from the RabbitMQ service process

Detection Strategies

• Monitor file system activity in the RabbitMQ installation directory for new or modified executable files
• Implement file integrity monitoring (FIM) on the RabbitMQ installation directory to detect unauthorized changes
• Review Windows Security Event logs for suspicious process creation events associated with the RabbitMQ service
• Audit user accounts with write access to the RabbitMQ installation directory

Monitoring Recommendations

• Enable detailed Windows audit logging for file creation and modification in the RabbitMQ installation path
• Configure SIEM rules to alert on unexpected binary files in application directories
• Implement endpoint detection and response (EDR) solutions to monitor for DLL hijacking patterns
• Regularly audit directory permissions for the RabbitMQ installation folder

How to Mitigate CVE-2020-5419

Immediate Actions Required

• Upgrade RabbitMQ to version 3.8.7 or later immediately
• Audit and restrict write permissions on the RabbitMQ installation directory to only essential administrative accounts
• Review all files in the RabbitMQ installation directory for unexpected or unauthorized binaries
• Implement the principle of least privilege for accounts with access to RabbitMQ servers

Patch Information

VMware has released a security patch addressing this vulnerability in RabbitMQ version 3.8.7. Organizations should upgrade to version 3.8.7 or later to remediate this vulnerability. The security advisory and patch information can be found at the VMware Security Advisory.

Workarounds

• Restrict write access to the RabbitMQ installation directory to only trusted administrators
• Implement Windows Software Restriction Policies (SRP) or AppLocker rules to prevent unauthorized executable execution from the installation directory
• Enable Windows Defender Application Control to whitelist only legitimate RabbitMQ binaries
• Regularly audit file system permissions and user access to the RabbitMQ installation path

# Restrict permissions on RabbitMQ installation directory (PowerShell)
# Replace with your actual RabbitMQ installation path
$rabbitPath = "C:\Program Files\RabbitMQ Server\rabbitmq_server-3.8.x"
icacls $rabbitPath /inheritance:r
icacls $rabbitPath /grant:r "SYSTEM:(OI)(CI)F"
icacls $rabbitPath /grant:r "Administrators:(OI)(CI)F"
icacls $rabbitPath /grant:r "BUILTIN\Users:(OI)(CI)RX"