CVE-2021-40491 Explained : Impact and Mitigation

This CVE record relates to a vulnerability in the GNU Inetutils FTP client that exposes a security issue due to incomplete address validation.

Understanding CVE-2021-40491

This section provides insight into the nature and impact of the CVE.

What is CVE-2021-40491?

The ftp client in GNU Inetutils before version 2.2 fails to validate addresses returned by PASV/LSPV responses against the server address, leading to a potential security risk. The issue is comparable to CVE-2020-8284 observed in curl.

The Impact of CVE-2021-40491

The vulnerability in CVE-2021-40491 allows malicious entities to potentially exploit the FTP client in GNU Inetutils, compromising the integrity and confidentiality of data transfers.

Technical Details of CVE-2021-40491

In this section, we delve into the technical aspects of the CVE.

Vulnerability Description

The vulnerability arises from the failure to verify addresses in PASV/LSPV responses against the authentic server address, leaving the FTP client susceptible to address spoofing attacks.

Affected Systems and Versions

Vendor: n/a
Product: n/a
Versions Affected: All versions before 2.2

Exploitation Mechanism

The security flaw in GNU Inetutils FTP client can be exploited by malicious actors providing fraudulent addresses in PASV/LSPV responses to deceive the client and potentially perform unauthorized actions.

Mitigation and Prevention

Explore the measures to address and prevent CVE-2021-40491.

Immediate Steps to Take

Update GNU Inetutils to version 2.2 or above to patch the vulnerability.
Implement network segmentation to restrict FTP client access.

Long-Term Security Practices

Regularly monitor and audit FTP client activities for suspicious behavior.
Educate users on secure FTP usage and caution against interacting with untrusted servers.

Patching and Updates

Ensure timely installation of security updates and patches for GNU Inetutils to enhance system security and protect against known vulnerabilities.