CVE-2023-27492 : Vulnerability Insights and Analysis
Learn about CVE-2023-27492 where Envoy crashes due to large request bodies in Lua filter. Impact, mitigation steps, and affected versions.
This CVE involves an issue where Envoy may crash when a large request body is processed in the Lua filter.
Understanding CVE-2023-27492
This vulnerability affects the Envoy proxy and can lead to denial of service when processing large request bodies with the Lua filter enabled.
What is CVE-2023-27492?
Envoy, an open-source edge and service proxy for cloud-native applications, is susceptible to a denial-of-service vulnerability in versions prior to 1.26.0, 1.25.3, 1.24.4, 1.23.6, and 1.22.9. Attackers can exploit this vulnerability by sending large request bodies for routes with the Lua filter enabled, causing crashes.
The Impact of CVE-2023-27492
The impact of this CVE is rated as medium severity (CVSS base score of 4.8) with high availability impact. Although it does not affect confidentiality or integrity, it requires low privileges and user interaction for exploitation.
Technical Details of CVE-2023-27492
This section delves into the technical aspects of the vulnerability.
Vulnerability Description
The vulnerability arises from the Lua filter in Envoy, allowing attackers to crash the proxy by sending large request bodies to routes with the Lua filter enabled.
Affected Systems and Versions
Versions affected by this vulnerability include Envoy versions prior to 1.26.0, 1.25.3, 1.24.4, 1.23.6, and 1.22.9.
Exploitation Mechanism
To exploit this vulnerability, attackers can send large request bodies for routes using the Lua filter, triggering crashes in affected Envoy versions.
Mitigation and Prevention
It is crucial to take immediate steps to mitigate the risks posed by CVE-2023-27492.
Immediate Steps to Take
As a workaround, it is recommended to update Envoy to versions 1.26.0, 1.25.3, 1.24.4, 1.23.6, or 1.22.9 where the Lua filter no longer invokes the coroutine if the filter has been reset. Additionally, for those using Lua filter buffering, implementing the buffer filter can help avoid local reply triggers.
Long-Term Security Practices
Implementing regular updates and patches for Envoy is essential to maintain a secure environment. Monitoring security advisories and staying informed about potential vulnerabilities can aid in safeguarding systems.
Patching and Updates
Ensure timely installation of patches and updates provided by Envoy to address known vulnerabilities and enhance the security posture of the proxy environment.