CVE-2023-27484 : Exploit Details and Defense Strategies

This CVE involves an unchecked fieldpath index in Composition's patches that can lead to arbitrary memory allocation in Crossplane, impacting certain versions of the Crossplane runtime.

Understanding CVE-2023-27484

This vulnerability in Crossplane's runtime can result in excessive memory usage due to an issue related to patch evaluation in Compositions.

What is CVE-2023-27484?

In affected versions of the Crossplane runtime, a highly privileged user could specify an arbitrarily high index in a patch's

ToFieldPath

, causing excessive memory usage when the Composition is selected for a Composite resource. This could potentially lead to the Pod being OOM-killed.

The Impact of CVE-2023-27484

The impact of this vulnerability is categorized as having a medium severity level, with high availability impact. While there is no impact on confidentiality or integrity, the potential for arbitrary memory allocation poses a significant risk to affected systems.

Technical Details of CVE-2023-27484

The following technical details outline the vulnerability, affected systems, and the exploitation mechanism.

Vulnerability Description

The issue arises when an already highly privileged user defines an excessively high index in a patch's

ToFieldPath

, causing the target slice to grow significantly, leading to excessive memory usage and potential Pod termination due to out-of-memory issues.

Affected Systems and Versions

The vulnerability impacts Crossplane versions < 1.9.2, >= 1.10.0, < 1.10.3, and >= 1.11.0, < 1.11.2.

Exploitation Mechanism

By manipulating the index value in a patch's

ToFieldPath

, a malicious user can trigger the excessive memory allocation scenario in the affected versions of Crossplane.

Mitigation and Prevention

To address CVE-2023-27484 and prevent potential exploits, users are advised to take the following steps:

Immediate Steps to Take

Upgrade to the patched versions: 1.11.2, 1.10.3, or 1.9.2 to eliminate the vulnerability.
If upgrading is not feasible, restrict write privileges on Compositions to admin users only as a temporary workaround.

Long-Term Security Practices

Implement secure coding practices, regular security audits, and stay informed about security advisories and patches to mitigate future vulnerabilities effectively.

Patching and Updates

Regularly monitor for security updates and patch your systems promptly to ensure protection against known vulnerabilities like CVE-2023-27484.