CVE-2021-32777 : Vulnerability Insights and Analysis

In Envoy versions, specifically crafted requests may bypass authorization due to incorrect concatenation of multiple value request headers in the ext-authz extension. This could lead to privilege escalation within affected versions. Learn more about the impact and mitigation strategies below.

Understanding CVE-2021-32777

This section provides an overview of the CVE-2021-32777 vulnerability in Envoy.

What is CVE-2021-32777?

CVE-2021-32777 involves incorrect concatenation of multiple value request headers in the ext-authz extension of Envoy, potentially permitting unauthorized requests to bypass the intended authorization process.

The Impact of CVE-2021-32777

The vulnerability poses a high severity risk with a CVSS base score of 8.6. Attackers could exploit this flaw to escalate privileges, especially when using the ext-authz extension or services utilizing multiple value headers for authorization.

Technical Details of CVE-2021-32777

Explore the technical aspects of the CVE-2021-32777 vulnerability to better understand its implications.

Vulnerability Description

In affected versions of Envoy, the ext-authz extension fails to correctly merge multiple request header values, allowing malicious requests to bypass authorization mechanisms.

Affected Systems and Versions

Envoy version >= 1.19.0, < 1.19.1
Envoy version >= 1.18.0, < 1.18.4
Envoy version >= 1.17.0, < 1.17.4
Envoy version >= 1.16.0, < 1.16.5

Exploitation Mechanism

Attackers can exploit this vulnerability by sending specifically crafted requests that take advantage of the incorrect handling of multiple value request headers in the ext-authz extension.

Mitigation and Prevention

Discover the steps to mitigate and prevent the CVE-2021-32777 vulnerability in Envoy.

Immediate Steps to Take

Update Envoy to versions 1.19.1, 1.18.4, 1.17.4, 1.16.5 to address the ext-authz extension issue.
Monitor network traffic for any suspicious activity that may indicate exploitation of the vulnerability.

Long-Term Security Practices

Regularly update Envoy to the latest versions to ensure that security patches are applied promptly.
Implement network segmentation and access controls to limit the impact of potential attacks.

Patching and Updates

Stay informed about security advisories from Envoyproxy and apply patches promptly to protect your systems from known vulnerabilities.