CVE-2019-19271 Explained : Impact and Mitigation

A vulnerability has been identified in tls_verify_crl in ProFTPD version 1.3.6 and earlier, allowing clients with revoked certificates to establish a connection with the server.

Understanding CVE-2019-19271

This CVE involves an incorrect iteration variable in the process of checking client certificates against the Certificate Revocation List (CRL) entries.

What is CVE-2019-19271?

An issue in tls_verify_crl in ProFTPD before version 1.3.6 allows clients with revoked certificates to connect to the server due to a flaw in the iteration variable.

The Impact of CVE-2019-19271

The vulnerability can lead to overlooked CRL entries, enabling unauthorized clients to establish connections with the server.

Technical Details of CVE-2019-19271

This section provides more in-depth technical insights into the CVE.

Vulnerability Description

The flaw in tls_verify_crl in ProFTPD versions prior to 1.3.6 results from an incorrect iteration variable, allowing revoked certificate holders to connect to the server.

Affected Systems and Versions

ProFTPD version 1.3.6 and earlier

Exploitation Mechanism

Attackers can exploit this vulnerability by using revoked certificates to establish connections with the server.

Mitigation and Prevention

Protect your systems from CVE-2019-19271 with the following steps:

Immediate Steps to Take

Upgrade ProFTPD to version 1.3.6 or later to mitigate the vulnerability.
Monitor and restrict network access to prevent unauthorized connections.

Long-Term Security Practices

Regularly update and patch software to address known vulnerabilities.
Implement proper certificate management practices to ensure the security of client connections.

Patching and Updates

Apply patches and updates provided by ProFTPD to fix the vulnerability and enhance system security.