CVE-2020-15136 Explained : Impact and Mitigation

In ectd before versions 3.4.10 and 3.3.23, gateway TLS authentication is only applied to endpoints detected in DNS SRV records. This vulnerability has been assigned a CVSS base score of 6.5, indicating a medium severity level.

Understanding CVE-2020-15136

This CVE relates to improper authentication in etcd, affecting versions prior to 3.4.10 and 3.3.23.

What is CVE-2020-15136?

CVE-2020-15136 is a security vulnerability in etcd versions before 3.4.10 and 3.3.23, where gateway TLS authentication is limited to endpoints identified in DNS SRV records.

The Impact of CVE-2020-15136

CVSS Base Score: 6.5 (Medium)
Attack Vector: Network
Confidentiality Impact: High
Integrity Impact: Low
Privileges Required: None
Scope: Unchanged
User Interaction: None
Attack Complexity: High
Availability Impact: None

Technical Details of CVE-2020-15136

This section provides detailed technical information about the vulnerability.

Vulnerability Description

The vulnerability in etcd versions before 3.4.10 and 3.3.23 allows gateway TLS authentication only for endpoints detected in DNS SRV records.

Affected Systems and Versions

Affected Product: etcd
Vendor: etcd-io
Vulnerable Versions:
= 3.4.0, < 3.4.10

< 3.3.23

Exploitation Mechanism

The issue arises when starting a gateway, where TLS authentication is exclusively attempted on endpoints identified in DNS SRV records for a given domain, neglecting authentication against endpoints provided in the --endpoints flag.

Mitigation and Prevention

To address CVE-2020-15136, follow these steps:

Immediate Steps to Take

Upgrade etcd to version 3.4.10 or 3.3.23.
Implement network security measures to mitigate unauthorized access.

Long-Term Security Practices

Regularly update and patch etcd to the latest secure versions.
Conduct security audits to identify and address potential vulnerabilities.

Patching and Updates

Apply patches provided by etcd to fix the authentication issue.