CVE-2023-39059
📋 TL;DR
CVE-2023-39059 is a remote code execution vulnerability in Ansible Semaphore where an attacker can execute arbitrary commands via crafted extra variables. This affects administrators and users of vulnerable Semaphore instances, potentially allowing complete system compromise.
💻 Affected Systems
- Ansible Semaphore
📦 What is this software?
Ansible Semaphore by Ansible Semaphore
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with attacker gaining root/administrator privileges, data exfiltration, lateral movement, and persistent backdoor installation.
Likely Case
Unauthorized command execution leading to service disruption, data manipulation, and potential privilege escalation within the Semaphore environment.
If Mitigated
Limited impact with proper input validation and execution sandboxing, potentially only affecting Semaphore application data.
🎯 Exploit Status
Exploit involves crafting malicious payload in extra variables parameter, with public proof-of-concept available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: v2.8.91 or later
Vendor Advisory: https://github.com/ansible-semaphore/semaphore/releases
Restart Required: Yes
Instructions:
1. Backup current configuration and data. 2. Stop Semaphore service. 3. Update to v2.8.91 or later using package manager or manual download. 4. Restart Semaphore service. 5. Verify version and functionality.
🔧 Temporary Workarounds
Disable Extra Variables
allTemporarily disable or restrict access to extra variables functionality
Modify Semaphore configuration to disable extra_vars feature
Network Segmentation
allRestrict network access to Semaphore instance
Configure firewall rules to limit access to trusted IPs only
🧯 If You Can't Patch
- Implement strict input validation and sanitization for extra variables
- Deploy Semaphore in isolated network segment with minimal privileges
🔍 How to Verify
Check if Vulnerable:
Check if Semaphore version is v2.8.90 or earlier and extra variables feature is accessibleCheck Version:
semaphore --version or check web interface about pageVerify Fix Applied:
Confirm version is v2.8.91 or later and test extra variables functionality with safe payloads📡 Detection & Monitoring
Log Indicators:
- Unusual command execution patterns
- Suspicious extra variables payloads
- Unexpected process creation
Network Indicators:
- Anomalous outbound connections from Semaphore host
- Unexpected command and control traffic
SIEM Query:
source="semaphore.log" AND ("extra_vars" OR "command_execution") AND suspicious_patterns🔗 References
- https://gist.github.com/Alevsk/1757da24c5fb8db735d392fd4146ca3a
- https://www.alevsk.com/2023/07/a-quick-story-of-security-pitfalls-with-execcommand-in-software-integrations/
- https://gist.github.com/Alevsk/1757da24c5fb8db735d392fd4146ca3a
- https://www.alevsk.com/2023/07/a-quick-story-of-security-pitfalls-with-execcommand-in-software-integrations/
