CVE-2019-19269 : Exploit Details and Defense Strategies

ProFTPD through version 1.3.6b has a vulnerability in the tls_verify_crl function that may lead to dereferencing a NULL pointer. This issue arises when an empty CRL is installed by a system administrator, resulting in a pointer dereference during client certificate validation in a TLS client/server mutual authentication setup.

Understanding CVE-2019-19269

This CVE identifies a specific vulnerability in ProFTPD versions up to 1.3.6b.

What is CVE-2019-19269?

CVE-2019-19269 is a vulnerability in ProFTPD that can be exploited to trigger a NULL pointer dereference, potentially leading to a denial of service or other security implications.

The Impact of CVE-2019-19269

The vulnerability in tls_verify_crl function of ProFTPD through version 1.3.6b can result in dereferencing a NULL pointer, which may be exploited by an attacker to disrupt the service or execute arbitrary code.

Technical Details of CVE-2019-19269

ProFTPD through version 1.3.6b is affected by this vulnerability.

Vulnerability Description

The issue lies in the tls_verify_crl function, where a NULL pointer dereference can occur when encountering an empty CRL installed by a system administrator during client certificate validation.

Affected Systems and Versions

Product: ProFTPD
Vendor: N/A
Versions affected: Up to 1.3.6b

Exploitation Mechanism

The vulnerability is triggered during the validation of a client's certificate in a TLS client/server mutual authentication configuration.

Mitigation and Prevention

It is crucial to take immediate steps to address and prevent exploitation of this vulnerability.

Immediate Steps to Take

Update ProFTPD to a patched version that addresses the vulnerability.
Monitor for any unusual activity on the network that could indicate exploitation.

Long-Term Security Practices

Regularly update and patch software to mitigate known vulnerabilities.
Implement network segmentation and access controls to limit the impact of potential attacks.

Patching and Updates

Ensure that ProFTPD is regularly updated to the latest secure version to prevent exploitation of this vulnerability.