CVE-2019-9901 Explained : Impact and Mitigation

CVE-2019-9901 was published on March 29, 2019, and affects Envoy versions prior to 1.9.0. This vulnerability allows a remote attacker to bypass access control restrictions by creating a specially crafted URL path.

Understanding CVE-2019-9901

Envoy, before version 1.9.0, lacks proper normalization of HTTP URL paths, enabling attackers to exploit this weakness.

What is CVE-2019-9901?

Envoy versions earlier than 1.9.0 do not perform normalization of HTTP URL paths, allowing attackers to create relative paths to evade access control restrictions.

The Impact of CVE-2019-9901

This vulnerability could be exploited by remote attackers to bypass access control policies and gain unauthorized access to resources beyond the intended scope.

Technical Details of CVE-2019-9901

This section provides more in-depth technical details of the CVE.

Vulnerability Description

Envoy versions prior to 1.9.0 do not normalize HTTP URL paths, enabling attackers to craft relative paths to bypass access controls.

Affected Systems and Versions

Product: N/A
Vendor: N/A
Versions affected: Prior to 1.9.0

Exploitation Mechanism

Attack Complexity: High
Attack Vector: Network
Availability Impact: Low
Confidentiality Impact: Low
Integrity Impact: Low
Privileges Required: None
Scope: Changed
User Interaction: None

Mitigation and Prevention

Protecting systems from CVE-2019-9901 requires immediate actions and long-term security practices.

Immediate Steps to Take

Update Envoy to version 1.9.0 or later to mitigate the vulnerability.
Implement proper access controls and input validation mechanisms.

Long-Term Security Practices

Regularly monitor and audit URL path normalization processes.
Conduct security training for developers to raise awareness of secure coding practices.

Patching and Updates

Stay informed about security advisories and updates from Envoy.
Apply patches promptly to address any newly discovered vulnerabilities.