CVE-2024-56406: Buffer Overflow Vulnerability in Perl Leading to Potential Denial of Service and Code Execution

Overview

A critical vulnerability labelled as CVE-2024-56406 has been identified within Perl, a widely-used general-purpose scripting language. Specifically, this vulnerability affects release branches 5.34, 5.36, 5.38, and 5.40 including development versions from 5.33.1 through 5.41.10. This vulnerability, if exploited, could lead to a Denial of Service and possibly Code Execution attacks on platforms that lack sufficient defenses. It is of utmost importance for organizations using Perl to understand this vulnerability and take immediate steps to mitigate the potential risks.

Vulnerability Summary

CVE ID: CVE-2024-56406
Severity: High (CVSS: 8.6)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: System compromise, data leakage

Affected Products

Product | Affected Versions

Perl | 5.34, 5.36, 5.38, 5.40, 5.33.1 through 5.41.10

How the Exploit Works

This vulnerability is a heap buffer overflow that occurs when there are non-ASCII bytes in the left-hand-side of the `tr` operator in Perl. The function `S_do_trans_invmap` can overflow the destination pointer `d`, which can lead to a segmentation fault. This fault condition can potentially be exploited by an attacker to execute arbitrary code or crash the application, leading to a denial of service.

Conceptual Example Code

An example of how this vulnerability might be exploited is as follows:

$ perl -e '$_ = "\x{FF}" x 1000000; tr/\xFF/\x{100}/;'
Segmentation fault (core dumped)

This command artificially creates a string with a large number of non-ASCII characters and attempts to translate these using the `tr` operator, causing a buffer overflow and a subsequent segmentation fault.

Mitigation and Prevention

The recommended mitigation for CVE-2024-56406 is to apply the latest vendor patch that corresponds to your version of Perl. If this is not possible, consider using a Web Application Firewall (WAF) or Intrusion Detection System (IDS) as a temporary mitigation. These systems can be configured to detect and block attempts to exploit this vulnerability. However, these measures should be considered temporary, and applying the vendor patch should be the ultimate goal to fully mitigate the vulnerability.