If you're using Jenkins CCCC Plugin .6 or earlier, you might be at risk of XML external entity (XXE) attacks. This vulnerability has been assigned the Common Vulnerabilities and Exposures (CVE) ID of CVE-2022-45395. In this post, we will discuss the details of the vulnerability, its impact, and the steps you can take to mitigate it.
Vulnerability: XML External Entity (XXE) attacks
What Is An XXE Attack?
An XML external entity (XXE) attack is a technique that exploits vulnerabilities in an XML parser. An attacker can send malicious XML data to an affected parser, leading to unauthorized access to system files or sensitive data. XXE attacks can result in data theft, denial of service (DoS), or server-side request forgery (SSRF).
Plugin Vulnerability Details
The Jenkins CCCC Plugin is a popular plugin that allows you to collect CCCC (C and C++ Code Counter) reports as part of your Jenkins build, making it easier to measure the quality and maintainability of your codebase. However, the plugin does not configure its XML parser correctly to prevent XXE attacks in version .6 and earlier.
An attacker could send specially crafted XML data to an affected instance of the plugin, resulting in a successful XXE attack.
The vulnerability in the plugin is due to improper configuration of the XML parser. A sample XML configuration file for Jenkins CCCC Plugin might look like this:
<xml> <report> <filename>cccc.xml</filename> </report> </xml>
An attacker could modify this XML to include a malicious external entity, such as a link to a sensitive system file:
<!DOCTYPE foo [ <!ENTITY xxe SYSTEM "file:///etc/passwd"> ]> <xml> <report> <filename>&xxe;</filename> </report> </xml>
When the affected Jenkins CCCC Plugin processes the XML data containing the malicious external entity, it can result in unauthorized access to the sensitive system file.
 Jenkins Security Advisory: https://www.jenkins.io/security/advisory/2022-01-18/
 CVE Details Page: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-45395
A successful exploit of the vulnerability might lead to
1. Data theft: An attacker can access sensitive or private data stored in the target system using malicious external entities.
2. Denial of Service (DoS): The attacker can make the application unresponsive or crash by sending malicious XML data containing an excessively large external entity.
3. Server-Side Request Forgery (SSRF): An attacker can use the XXE vulnerability to make requests to internal services or third-party systems from the target system, potentially bypassing firewalls or security controls.
As this vulnerability affects Jenkins CCCC Plugin .6 and earlier, we recommend upgrading to the latest version as soon as possible to protect your systems from potential XXE attacks. Additionally, consider:
CVE-2022-45395 highlights the importance of proper configuration when using XML parsers in your applications. Stay up-to-date with security advisories and make sure to configure your systems and plugins in a secure manner to minimize the risk of vulnerable entry points for attackers. And always, keep your software updated to ensure the highest level of security and performance.
Published on: 11/15/2022 20:15:00 UTC
Last modified on: 11/20/2022 03:02:00 UTC