Mitigating CVE-2013-1896: Privilege Escalation Vulnerability in Puppet
Tech Stack: Puppet (Configuration Management Tool)
Date(s) Issued:
- Published: April 9, 2013
- Last Modified: April 10, 2013
Criticality:
- CVSS Score: 7.2 (High)
- Impact: Exploitation of this vulnerability can lead to privilege escalation, enabling an attacker to execute arbitrary code as root.
Overview:
CVE-2013-1896 is a critical privilege escalation vulnerability affecting Puppet, a configuration management tool. Puppet versions prior to 3.2.2 and Puppet Enterprise versions prior to 2.8.0 were vulnerable.
The issue arises due to inadequate input sanitization in Puppet's REST API. An attacker with access to the API could exploit the vulnerability by uploading malicious Puppet modules. These modules would then be executed with root privileges, potentially compromising the entire system.
Affected Versions:
- Puppet Open Source: Versions prior to 3.2.2
- Puppet Enterprise: Versions prior to 2.8.0
Exploitation Method:
- An attacker uploads a crafted Puppet module containing malicious code via the REST API.
- The module is executed with elevated privileges, granting the attacker unauthorized root access.
Solution/Mitigation:
1. Upgrade:
The most effective mitigation is to upgrade Puppet to a patched version:
- Upgrade Puppet Open Source to version 3.2.2 or later.
- Upgrade Puppet Enterprise to version 2.8.0 or later.
2. Restrict API Access:
Until the upgrade is implemented, restrict access to the Puppet REST API:
- Use firewall rules or network access controls to limit API access to trusted IP ranges.
- Apply authentication and authorization mechanisms for all API requests.
3. Harden Puppet Master Configuration:
- Disable unauthenticated module uploads.
- Enforce strict permissions for Puppet directories and files.
- Regularly monitor logs for suspicious activities or unauthorized uploads.
4. Sanitize Input:
Ensure proper validation and sanitization of all inputs received by the Puppet Master.
5. Apply Least Privilege:
Run the Puppet Master and agent processes with the minimum privileges required, avoiding root whenever feasible.
6. Monitor System Activity:
- Enable verbose logging for Puppet operations.
- Monitor for abnormal activities such as unexpected module uploads or unrecognized processes.
Verification:
-
Verify the Upgrade: After upgrading, confirm the version with the following command:
Ensure it matches the patched version or later.
-
Test API Restrictions: Use a network scanner to verify that the REST API is only accessible from authorized IP ranges.
-
Review Logs: Check logs to ensure there are no unauthorized access attempts post-mitigation.
Additional Information:
