CVE-2018-19148 : Security Advisory and Response

Caddy server version 0.11.0 has a vulnerability that can lead to the exposure of incorrect certificates, potentially aiding attackers in enumerating hostnames.

Understanding CVE-2018-19148

What is CVE-2018-19148?

Caddy server version 0.11.0 vulnerability allows attackers to enumerate hostnames by exploiting the server's behavior of serving incorrect certificates for certain invalid requests.

The Impact of CVE-2018-19148

This vulnerability can enable attackers to discover the existence of and relationships between hostnames that were not intended to be publicly known.

Technical Details of CVE-2018-19148

Vulnerability Description

Caddy server version 0.11.0 sends incorrect certificates for specific invalid requests, making it easier for attackers to enumerate hostnames.

Affected Systems and Versions

Product: N/A
Vendor: N/A
Version: N/A

Exploitation Mechanism

When the server cannot find a matching virtual host for a Host header, it serves the X.509 certificate for a randomly selected virtual host from its configuration.
Attackers can enumerate all certificates on the server by repeatedly sending requests with a nonexistent hostname in the Host header.

Mitigation and Prevention

Immediate Steps to Take

Upgrade Caddy server to a patched version.
Monitor server logs for unusual certificate requests.

Long-Term Security Practices

Regularly update and patch server software.
Implement network segmentation to limit exposure of sensitive information.

Patching and Updates

Apply the latest patches and updates provided by Caddy server to address this vulnerability.