CVE-2020-2207: Reflected XSS vulnerability in Jenkins VncViewer Plugin
Summary
CVE-2020-2207: Reflected XSS vulnerability in Jenkins VncViewer Plugin. Affects org.jenkins-ci.plugins:vncviewer versions < 1.8. Fixed in 1.8. How to fix ↓
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Background
The Jenkins VncViewer Plugin is a Maven-based plugin that allows users to view VNC (Virtual Network Computing) sessions within the Jenkins environment. It provides a convenient way to monitor and interact with VNC servers directly from the Jenkins interface. The plugin is widely used by Jenkins users to streamline their workflow and enhance collaboration. However, versions 1.7 and earlier of the VncViewer Plugin are vulnerable to a reflected cross-site scripting (XSS) attack.
Vulnerability Detail
The vulnerability in the VncViewer Plugin arises from a lack of proper input validation and output encoding. Specifically, the plugin fails to escape a parameter value in the checkVncServ form validation endpoint output. This allows an attacker to inject malicious scripts or HTML code into the output, which will be executed when viewed by other users. The impact of this vulnerability can range from unauthorized data disclosure to the execution of arbitrary code within the context of the affected user's session. The Common Vulnerabilities and Exposures (CVE) identifier for this vulnerability is CVE-2020-2207.
How To Fix
Minimum fixed version
1.8
This is the first release that contains the fix.
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Workaround
If upgrading to version 1.8 is not immediately feasible, a temporary workaround is to disable or remove the VncViewer Plugin from the Jenkins installation. This will eliminate the risk of exploitation through this specific vulnerability. However, it may impact the functionality and convenience provided by the plugin. Therefore, upgrading to the latest secure version is the recommended long-term solution.
Conclusion
The Jenkins VncViewer Plugin versions 1.7 and earlier are vulnerable to a reflected XSS attack. This can lead to unauthorized data disclosure, session hijacking, or the execution of arbitrary code. To mitigate this vulnerability, it is recommended to upgrade to version 1.8 or later. Alternatively, users can temporarily disable or remove the plugin. Regularly updating all plugins is also advised to ensure the latest security patches are applied. For further support and assistance, please contact DevNack.com.
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FAQ
The vulnerability allows an attacker to execute arbitrary code or scripts within the context of the affected user's session. This can lead to unauthorized data disclosure, session hijacking, or other malicious activities.
You can use the Vulert Playground (https://vulert.com/scanner) to check if your Jenkins installation is affected by this vulnerability. Simply provide your pom.xml file, and Vulert will analyze it in real-time to identify any open-source vulnerabilities, including CVE-2020-2207.
At the time of this advisory, there are no known public exploits specifically targeting this vulnerability. However, it is important to promptly apply the recommended security updates to mitigate the risk.
Yes, you can temporarily mitigate the vulnerability by disabling or removing the VncViewer Plugin from your Jenkins installation. However, this may impact the functionality provided by the plugin. Upgrading to the latest secure version is the recommended long-term solution.
For further support and assistance with vulnerability remediation, you can contact info@devnack.com. Our team of experts will be happy to assist you in securing your Jenkins installation.
