Adobe Acrobat Reader is a widely-used software for viewing, printing, signing, and annotating Portable Document Format (PDF) files. In versions 23.006.20360 (and earlier) and 20.005.30524 (and earlier), there is a critical vulnerability that could lead to the exposure of sensitive memory and serve as a bypass for security mitigations, such as Address Space Layout Randomization (ASLR). This vulnerability has been assigned the Common Vulnerabilities and Exposures (CVE) ID CVE-2023-44357.

Exploit Details

The vulnerability in question is an out-of-bounds read, which occurs when a program tries to read data past the end or before the beginning of a buffer. This can lead to the disclosure of potentially sensitive memory contents that may have been inaccessible under normal circumstances.

This vulnerability exists because Adobe Acrobat Reader does not properly validate a user-supplied value before using it in a memory read operation. When a user opens a maliciously crafted PDF file, the software will attempt to read data from an invalid location, resulting in the exposure of sensitive memory and potentially bypassing security mitigations such as ASLR.

An attacker could exploit this vulnerability by convincing a user to open a malicious PDF file, which can be done through phishing, social engineering, or other attack vectors. Note that exploitation of this vulnerability requires user interaction, as a victim must open the malicious file.

The following demo code snippet simulates the issue in Adobe Acrobat Reader

#include <stdio.h>

int main() {
  int buffer[4];
  int index = 5; // This value should be sanitized!
  int value;

  value = buffer[index];

  printf("Value: %d\n", value);

  return ;
}

In this example, the index 5 is used to access data outside the bounds of the buffer array, potentially causing an out-of-bounds read.

Adobe has acknowledged this vulnerability and published a security bulletin with more information

- Adobe Security Bulletin APSB23-44357

The vulnerability is also documented in the following CVE database

- CVE-2023-44357

Mitigation and Remediation

Adobe has released updates to address this vulnerability. Users are recommended to update their Adobe Acrobat Reader installations to versions 23.006.20361 or 20.005.30525, depending on the release track they are on. These updates can be obtained from Adobe's official website or by using the built-in software updater.

Conclusion

It is crucial to keep software up to date in order to prevent vulnerabilities from being exploited. Users of Adobe Acrobat Reader should apply the necessary updates and remain vigilant when opening PDF files from unfamiliar sources. Staying informed about the latest security advancements and known vulnerabilities can help users protect themselves and mitigate the risks associated with this and other similar issues.

Timeline

Published on: 11/16/2023 10:15:13 UTC
Last modified on: 11/22/2023 17:04:47 UTC