Horizon Alert
Summary of the vulnerability and why it matters
A path equivalence vulnerability exists in the Apache Tomcat Default Servlet. This flaw permits attackers to execute arbitrary code, disclose sensitive information, or modify uploaded files. This occurs when specific configurations are present, such as write access being enabled for the default servlet and support for partial PUT requests.
- Vulnerable component: Apache Tomcat Default Servlet
- Core weakness: Improper path validation with internal dots
- Main business impact: Remote code execution, data disclosure/tampering
Attack Path
How an attacker could exploit the issue
The described vulnerability in Apache Tomcat allows an attacker to gain control over a system. This can lead to remote code execution, unauthorized access to sensitive files, or the injection of malicious content into uploaded files. The attack leverages a path equivalence flaw within the default servlet, particularly when certain configurations, such as enabled writes and support for partial PUT requests, are in place. If file-based session persistence is also used with specific libraries, the risk of remote code execution increases.
- Exposed writes to the default servlet.
- Attacker knowledge of sensitive filenames.
- Attacker performs a partial PUT request.
- Attacker achieves code execution or data compromise.
Live Threat
Current exploitation, exposure, and threat context
This vulnerability in Apache Tomcat allows for remote code execution or information disclosure. Exploitation requires specific configurations, including enabled write access for the default servlet and support for partial PUT requests. The potential for attackers to gain control of systems or access sensitive data presents a significant business risk. Organizations using affected versions should prioritize addressing this issue.
- Likely attacker skill level: Low
- Required access or conditions: Specific configurations enabled
- Business risk or urgency: High
Priority actions
Operational Fix
Recommended remediation, mitigation, and detection steps
This vulnerability in Apache Tomcat could allow unauthorized access to sensitive files, modification of uploaded content, or remote code execution under specific configuration conditions. Organizations should prioritize identifying all instances of the affected software, implementing measures to reduce potential exposure, applying vendor-provided updates, and verifying the successful application of fixes. Continuous monitoring for related suspicious activities is also recommended to detect any residual or emergent threats.
- Identify all Apache Tomcat assets.
- Restrict default servlet write access.
- Upgrade Tomcat, verify fixes, monitor.
