CVE-2024-23839: Suricata Heap Use-After-Free Vulnerability in Versions Prior to 7..3 – Patch and Workaround

Suricata is a widely used open-source engine for Network Intrusion Detection System (NIDS), Intrusion Prevention System (IPS) and Network Security Monitoring (NSM) tasks. It functions by inspecting traffic passing through a network interface and triggering alerts or taking actions according to a ruleset loaded into the engine.

A heap use-after-free vulnerability (CVE-2024-23839) has been discovered in Suricata versions prior to 7..3, which could be exploited by an attacker using specially crafted traffic. In this long-read post, we'll provide an overview of the vulnerability, code snippets to explain the issue, links to original references, and details about how to work around and patch the exploit.

Vulnerability

The vulnerability stems from the improper handling of rulesets which use 'http.request_header' or 'http.response_header' keywords, resulting in a heap use-after-free condition. An attacker could potentially exploit this to execute arbitrary code, gain unauthorized access to a system, or cause a denial of service (DoS).

Code Snippet

To understand the vulnerability better, let's take a look at an example ruleset below, which utilizes the affected keywords:

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"Header Vulnerability Rule"; http.request_header; content:"SomeValue"; sid:1000001; rev:1;)
alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"Header Vulnerability Rule"; http.response_header; content:"SomeValue"; sid:1000002; rev:1;)

This ruleset uses both 'http.request_header' and 'http.response_header' keywords, making it susceptible to the heap-use-after-free vulnerability.

The vulnerability (CVE-2024-23839) was first disclosed by the following security advisory

- Suricata Security Advisory

Furthermore, the issue was reported and patches were submitted to the Suricata project on their official GitHub repository, which can be found at the following link:

- Suricata GitHub Repository

Exploit Details

The vulnerability can be triggered by an attacker sending specially crafted packets that contain particular headers to match the vulnerable ruleset. When such traffic is processed by the Suricata engine, the heap-use-after-free condition may be met, leading to potential exploitation.

Patch and Workaround

The Suricata project has addressed this vulnerability in the release of version 7..3, thus it is highly recommended to upgrade your Suricata engine to this latest version. Detailed upgrade instructions can be found in the official Suricata Documentation.

As a temporary workaround until the upgrade is carried out, you can also avoid the vulnerability by not using 'http.request_header' and 'http.response_header' keywords in your rulesets.

Conclusion

It is critical to stay informed about security vulnerabilities and apply the necessary patches and updates to secure your systems. In the case of CVE-2024-23839, upgrading your Suricata engine to version 7..3 or avoiding the use of vulnerable keywords is essential to protecting your network from potential exploitation.

Timeline

Published on: 02/26/2024 16:27:58 UTC
Last modified on: 03/07/2024 03:15:07 UTC