CVE-2023-27901 Explained : Impact and Mitigation

This CVE record pertains to a vulnerability identified in Jenkins, specifically versions 2.393 and earlier, LTS 2.375.3 and earlier. The vulnerability stems from the Apache Commons FileUpload library being used without specifying limits for the number of request parts, potentially leading to a denial of service attack.

Understanding CVE-2023-27901

This section will delve into the specifics of CVE-2023-27901, shedding light on what the vulnerability entails and its potential impact.

What is CVE-2023-27901?

CVE-2023-27901 highlights a flaw in Jenkins versions 2.393 and earlier, LTS 2.375.3 and earlier, where the Apache Commons FileUpload library lacks specified limits for request parts. This oversight can be exploited by malicious actors to trigger a denial of service attack.

The Impact of CVE-2023-27901

The impact of this vulnerability lies in its ability to enable attackers to conduct denial of service attacks on systems running the affected Jenkins versions. By leveraging this flaw, threat actors could disrupt the availability of Jenkins services and potentially cause downtime for affected organizations.

Technical Details of CVE-2023-27901

In this section, we will explore the technical aspects of CVE-2023-27901, including the vulnerability description, affected systems and versions, as well as the exploitation mechanism.

Vulnerability Description

The vulnerability in question arises from Jenkins 2.393 and earlier, LTS 2.375.3 and earlier utilizing the Apache Commons FileUpload library without setting limits for request parts, which was introduced in version 1.5 for CVE-2023-24998 in org.kohsuke.stapler.RequestImpl.

Affected Systems and Versions

The impacted systems include Jenkins versions 2.393 and earlier, LTS 2.375.3 and earlier. Notably, versions such as 2.394, 2.375.4, and 2.387.1 are unaffected by this vulnerability.

Exploitation Mechanism

Malicious actors can exploit this vulnerability by sending specially crafted requests to the affected Jenkins instances, leveraging the lack of limits for request parts in the Apache Commons FileUpload library to launch denial of service attacks.

Mitigation and Prevention

In this section, we will discuss steps that can be taken to mitigate the risks associated with CVE-2023-27901 and prevent potential exploitation.

Immediate Steps to Take

Organizations utilizing Jenkins versions 2.393 and earlier, LTS 2.375.3 and earlier should consider updating to unaffected versions such as 2.394, 2.375.4, or 2.387.1 to eliminate the vulnerability. Additionally, implementing network security measures to filter out malicious requests can help thwart potential denial of service attacks.

Long-Term Security Practices

To enhance overall security posture, organizations should regularly monitor and update their software dependencies, including libraries like Apache Commons FileUpload. Conducting routine security assessments and staying informed about emerging vulnerabilities within the Jenkins ecosystem is crucial for maintaining a resilient infrastructure.

Patching and Updates

Remaining vigilant for security advisories from Jenkins Project and promptly applying patches and updates is essential for addressing known vulnerabilities like CVE-2023-27901. By staying proactive in patch management practices, organizations can reduce the risk of exploitation and fortify their defenses against potential threats.