CVE-2022-1942: Heap-based Buffer Overflow Vulnerability in Vim (vim/vim) Repository Versions Prior to 8.2

A recent security advisory has reported a Heap-based Buffer Overflow vulnerability (CVE-2022-1942) affecting the widely popular text editor, Vim. The vulnerability had existed in the vim/vim GitHub repository, specifically in versions prior to 8.2. In this post, we delve into the vulnerability's details, the potential risks, and available mitigations. Code snippets are provided along with links to original references for better understanding.

Vulnerability Details

The vulnerability was discovered in the Vim text editor, primarily affecting versions prior to the 8.2 release. It is categorized as a Heap-based Buffer Overflow, which could result in arbitrary code execution if it is exploited by an attacker. The risk lies in the ability of the attacker to execute malicious code with the permission of the user running the affected application. Consequently, this vulnerability places systems that use vulnerable Vim versions at risk.

Code Snippet

The vulnerability is triggered when the user interacts with a maliciously crafted file or plugin. The following code snippet demonstrates an example scenario involving a vulnerable function:

int vulnerable_function(char *buf, int len) {
  char overflowed_buffer[256];
  ...
  strcpy(overflowed_buffer, buf);
  ...
}

In this example, the strcpy() function does not have a proper bounds check, which can result in a heap overflow that overwrites adjacent memory locations. An attacker can craft a file containing malicious content to exploit this vulnerability and potentially execute arbitrary code on the target system.

Original References

For more information on the vulnerability and the research that uncovered it, please refer to the following links:

1. CVE details of the vulnerability: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-1942
2. Vim/vim GitHub repository: https://github.com/vim/vim
3. Vim 8.2 release notes: https://github.com/vim/vim/blob/master/runtime/doc/version8.txt

Exploit Details

Exploiting this vulnerability primarily relies on a malicious file or plugin containing crafted data to trigger the Heap-based Buffer Overflow on systems running a vulnerable version of Vim. The attacker must persuade the user to interact with or open this file or plugin, effectively executing the malicious code. The code can then provide unauthorized access to the system, data exfiltration, or further infection with other malicious software.

Mitigation

The most effective mitigation for this vulnerability is to update Vim to version 8.2 or later, where the Heap-based Buffer Overflow vulnerability has been addressed. All users of Vim are encouraged to update their software to the latest version to safeguard their systems from potential attacks.

To check the current version of Vim installed on your system, run the following command

vim --version

If your Vim version is outdated, follow the appropriate instructions from the Vim documentation to update it: https://www.vim.org/download.php

Conclusion

The CVE-2022-1942 Heap-based Buffer Overflow vulnerability in Vim poses significant risks to systems running affected versions of the software. Users are encouraged to update their installations promptly to ensure the security of their devices. By staying aware of these vulnerabilities and patching your software in a timely manner, you can help keep your systems safe from the ever-present threat of cyber attacks.

Timeline

Published on: 05/31/2022 14:15:00 UTC
Last modified on: 08/26/2022 18:53:00 UTC