CVE-2021-1224 : Exploit Details and Defense Strategies

A vulnerability affecting multiple Cisco products has been identified with TCP Fast Open (TFO) used alongside the Snort detection engine. This vulnerability could be exploited by a remote attacker to bypass configured file policy for HTTP, potentially leading to the delivery of a malicious payload.

Understanding CVE-2021-1224

What is CVE-2021-1224?

The vulnerability in multiple Cisco products allows an unauthenticated attacker to bypass configured file policy for HTTP packets, exploiting an incorrect detection of the HTTP payload contained within the TFO connection handshake.

The Impact of CVE-2021-1224

Successful exploitation of this vulnerability can enable an attacker to circumvent configured file policies for HTTP packets, potentially allowing them to deliver harmful payloads.

Technical Details of CVE-2021-1224

Vulnerability Description

The vulnerability arises due to incorrect detection of the HTTP payload within the TFO connection handshake, allowing attackers to send crafted TFO packets with an HTTP payload through affected devices.

Affected Systems and Versions

Vendor: Cisco
Product: Cisco Firepower Threat Defense Software
Version: n/a
Status: Affected

Exploitation Mechanism

Attackers can exploit this vulnerability by sending specially crafted TFO packets with an HTTP payload through vulnerable devices, enabling them to bypass configured file policies for HTTP.

Mitigation and Prevention

Immediate Steps to Take

Make sure to monitor vendor advisories and security updates related to this vulnerability.
Implement network traffic monitoring to detect any suspicious TFO packets.
Consider applying relevant security patches as soon as they are released.

Long-Term Security Practices

Regularly update and patch the affected Cisco products to mitigate potential risks.
Enhance network segmentation and access controls to limit exposure to external threats.
Conduct regular security assessments and penetration testing to identify and address vulnerable areas.

Patching and Updates

Stay informed about security recommendations from relevant vendors and promptly apply patches and updates as they become available.