CVE-2024-20765 - Acrobat Reader Use After Free Vulnerability Leading to Arbitrary Code Execution

Adobe Acrobat Reader is a widely-used software that allows users to view and manipulate Portable Document Format (PDF) files. In versions 20.005.30539, 23.008.20470, and earlier, there exists a critical Use After Free vulnerability that, if exploited, could lead to arbitrary code execution on a victim's system. This post will delve into the details of CVE-2024-20765, including example code snippets and references to the original disclosures, as well as suggestions for mitigation.

Affected Versions

Acrobat Reader versions 20.005.30539, 23.008.20470, and earlier are affected by the reported vulnerability.

Vulnerability Details

In Acrobat Reader, a Use After Free vulnerability arises as a result of improper handling of memory objects. This issue occurs when a memory space is deallocated (or "freed") while a reference to it still exists, leading the program to potentially use the space after it has been freed. Consequently, an attacker could manipulate the freed memory space, execute arbitrary code, and ultimately take control of the system.

Exploitation

To exploit this vulnerability, an attacker must convince the victim to open a malicious file (e.g., a PDF) containing the malicious code. Once the file is opened, the code takes advantage of the Use After Free vulnerability, potentially leading to arbitrary code execution in the context of the current user.

This is a simple example illustrating the Use After Free vulnerability

#include <stdlib.h>

int main() {
  int *pointer = malloc(sizeof(int)); // Allocate memory space
  free(pointer); // Deallocate memory space
  *pointer = 42; // Use memory space after it has been freed (vulnerability)
}

In the real-world scenario, the program is much more complex, and the attacker would use a well-crafted PDF file to trigger the vulnerability.

For more detailed information about CVE-2024-20765, refer to the following resources

1. Adobe Security Bulletin: https://helpx.adobe.com/security/products/acrobat/apsb20-67.html
2. National Vulnerability Database (NVD): https://nvd/nist/gov/vuln/detail/CVE-2024-20765
3. CVE Details: https://www.cvedetails.com/cve/CVE-2024-20765/

Mitigation

To mitigate the risk posed byCVE-2024-20765, users are strongly encouraged to update their Acrobat Reader software to the latest version available. Adobe has released updates that address this issue. For more information on how to obtain and apply these updates, please visit the Adobe Security Bulletin here.

In addition to updating the software, users should always be cautious when opening files from untrusted sources. Only open files from trusted sources and verify their authenticity whenever possible.

Conclusion

By understanding the severity and implications of CVE-2024-20765, users can take appropriate steps to protect their systems from potential attacks that exploit the Use After Free vulnerability in Adobe Acrobat Reader. By staying up-to-date on software patches and exercising caution when opening files, users can maintain a secure environment and mitigate the risk of arbitrary code execution.

Timeline

Published on: 02/29/2024 17:15:07 UTC
Last modified on: 02/29/2024 18:06:42 UTC