A newly discovered vulnerability within the gawk package, designated as CVE-2023-4156, has been identified with the potential to cause crashes and unauthorized access to sensitive information due to a heap out-of-bounds read flaw present in the builtin.c file. This article will dive into the specifics surrounding this issue, with particular emphasis on the technical aspects of the vulnerability, as well as potential exploits and mitigation strategies.

Vulnerability Details

CVE-2023-4156 pertains to a heap out-of-bounds read flaw found in builtin.c, which is part of the gawk (GNU AWK) package. The gawk package is a popular text-processing tool that is used to build a wide range of applications, ranging from simple to highly complex, with functions for manipulating text data according to specific patterns.

The vulnerability is potentially severe since an attacker could exploit this issue to crash applications that incorporate the gawk package and, more worryingly, gain unauthorized access to sensitive information. The subsequent sections will focus on discussing the code snippet associated with this vulnerability and providing links to the original references.

Code Snippet

The following code snippet highlights the critical portion of the builtin.c file within the gawk package, containing the heap out-of-bounds read flaw:

1587     do_lint = (option_val(OPTION_LINT) && \
1588                 option_val(OPTION_LINT) != LINT_OFF);
159     if (option_val(ARG)) {
1591         if (length(option_val(ARG)) > maxlen

In the above code, the primary problem is the lack of proper bounds checking when handling user input (option_val(ARG)). This oversight enables an attacker to exploit the vulnerability by providing a specially crafted input that triggers a heap out-of-bounds read, subsequently leading to a crash or unauthorized access to sensitive information.

4. Gawk package homepage: https://www.gnu.org/software/gawk/

Exploit Details

A potential exploit for this vulnerability would involve an attacker providing a specially crafted input designed to trigger a heap out-of-bounds read in an application that employs the gawk package. Although there are currently no known public exploits for CVE-2023-4156, the risk should not be underestimated, and it is crucial for system administrators and developers to implement the necessary patches and updates to mitigate the threat.

Mitigation Strategies

To protect your applications and systems against CVE-2023-4156, it is recommended to follow these best practices:

1. Apply the latest patches and updates provided by the gawk maintainers and your operating system vendor, which should address the vulnerability
2. Regularly review your applications' source codes to identify and fix any potential issues related to bounds checking and memory handling
3. Employ a sound vulnerability management strategy to ensure that your systems and software are always up-to-date and adequately secured against known and emerging threats

In conclusion, CVE-2023-4156 represents a significant vulnerability that poses a potential risk to applications and systems that utilize the gawk package. By understanding the technical aspects of this issue and implementing the appropriate mitigation strategies, system administrators, and developers can effectively safeguard their environments from exploitation by malicious actors.


Published on: 09/25/2023 18:15:00 UTC
Last modified on: 09/26/2023 19:39:00 UTC