CVE-2023-26369: Critical Out-of-Bounds Write Vulnerability in Acrobat Reader - Exploit Details and How to Protect Yourself

Adobe's Acrobat Reader is one of the most popular tools for working with PDF files worldwide. However, even a widely used and reliable software like Acrobat Reader can fall prey to critical security vulnerabilities, posing both a risk to individual users and organizations alike.

In this post, we're diving deep into an out-of-bounds write vulnerability affecting multiple versions of Acrobat Reader, identified as CVE-2023-26369. We will discuss the exploit details, share code snippets, provide links to original references and, most importantly, advise on how to protect yourself from potential attacks exploiting this vulnerability.

Exploit Details

The vulnerability at the heart of CVE-2023-26369 is an out-of-bounds write issue, which occurs when data is written past the allocated memory buffer. This can corrupt adjacent data and, in the worst case, result in arbitrary code execution in the context of the current user.

Exploiting this vulnerability requires user interaction, meaning that the attacker must trick the victim into opening a malicious file. This could be done, for example, by sending the file via e-mail or hosting it on a compromised website.

References

For those who want to dive deep into the technical details, here are some links to original references for CVE-2023-26369:

- Official CVE Entry
- Adobe's Security Bulletin

Here's a code snippet illustrating the basic concept of an out-of-bounds write vulnerability

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
 
int main()
{
    char buffer[5];
    strcpy(buffer, "This is a very long string that will cause an out-of-bounds write");
    printf("%s\n", buffer);
    return ;
}

In this code, we allocate a buffer of size 5 bytes but then try to copy a much longer string into it, causing the data to overflow and overwrite adjacent memory. This simple example serves to illustrate the mechanics of an out-of-bounds write issue. In a real-world attack scenario, the malicious file would contain crafted data to trigger the vulnerability and execute malicious code on the victim's machine.

Prevention and Mitigation

To protect yourself from this critical vulnerability, the most important step is to update your Acrobat Reader to the latest version. Adobe has already released patches to fix the issue in the following software updates:

Acrobat Reader 20.005.30517

By updating your software as soon as possible, you will significantly reduce the risk of falling victim to attacks exploiting CVE-2023-26369.

It's also crucial to practice good security hygiene. Don't open suspicious files, especially if they come from unknown sources. If you receive a file via e-mail and don't recognize the sender, err on the side of caution and refrain from opening it. Similarly, avoid downloading files from untrusted websites.

Conclusion

CVE-2023-26369 is a serious security vulnerability affecting multiple versions of Acrobat Reader. By understanding the exploit details, keeping up-to-date with software patches, and practicing safe computing habits, you can help protect yourself and your organization from potential attacks.

Stay safe, and remember always to be vigilant when dealing with files from unfamiliar sources.

Timeline

Published on: 09/13/2023 09:15:00 UTC
Last modified on: 09/15/2023 13:44:00 UTC