CVE-2021-39162 : Vulnerability Insights and Analysis
Discover details of CVE-2021-39162 affecting Pomerium, an identity-aware access proxy, due to incorrect processing of H2 GOAWAY + SETTINGS frames, potentially leading to denial-of-service attacks.
Pomerium, an open-source identity-aware access proxy, is affected by a vulnerability in the handling of H2 GOAWAY + SETTINGS frames.
Understanding CVE-2021-39162
This CVE involves incorrect processing of specific frames in the Envoy-based Pomerium, potentially leading to a denial-of-service attack in the presence of untrusted upstream servers.
What is CVE-2021-39162?
Pomerium, which is built on Envoy, may crash if it receives H/2 GOAWAY and SETTINGS frames simultaneously, posing a risk of DoS when interacting with untrusted upstream servers.
The Impact of CVE-2021-39162
The vulnerability has a CVSS base score of 8.6 (High severity) with a LOW attack complexity and HIGH availability impact. If only trusted upstreams are configured, the risk of exploitation is reduced.
Technical Details of CVE-2021-39162
This section delves into specific technical aspects of the CVE.
Vulnerability Description
The issue arises due to the abnormal termination of Envoy when specific frames are handled concurrently, potentially leading to service disruption.
Affected Systems and Versions
- Product: Pomerium
- Vendor: Pomerium
- Versions Affected: >= 0.15.0, < 0.15.1
Exploitation Mechanism
The vulnerability can be exploited by sending a malicious combination of frames to trigger the abnormal termination of Envoy within Pomerium.
Mitigation and Prevention
Explore the recommended steps to mitigate and prevent the exploitation of this vulnerability.
Immediate Steps to Take
- Upgrade Pomerium to version 0.15.1 containing the patched Envoy binary to mitigate the vulnerability.
- Review and restrict the configuration to allow trusted upstream connections only.
Long-Term Security Practices
- Regularly monitor security advisories and updates for Pomerium and related components.
- Implement network segmentation and least privilege access controls to minimize attack surface.
Patching and Updates
- Stay informed about security patches and updates provided by Pomerium and Envoy to address vulnerabilities promptly.