CVE-2023-44371 - Critical Use After Free Vulnerability Found in Adobe Acrobat Reader Leading to Arbitrary Code Execution

Adobe Acrobat Reader, the widely used and trusted PDF reader, has been found to have a critical vulnerability in versions 23.006.20360 (and earlier) and 20.005.30524 (and earlier). This vulnerability, identified as CVE-2023-44371, could lead to a use-after-free scenario, resulting in arbitrary code execution in the context of the current user. Victim interaction is required for successful exploitation, as the user must open a malicious file that triggers the vulnerability.

In this post, we will discuss the specifics of this vulnerability, provide code snippets that demonstrate how the vulnerability can be exploited, and offer links to original references. We will also discuss mitigation steps that can be taken to protect yourself against this vulnerability.

Vulnerability Details

A use-after-free vulnerability occurs when an application frees a memory space but continues to use a pointer that references the now freed memory. This can lead to unintended behavior, including the execution of arbitrary code by an attacker. In the case of CVE-2023-44371, the vulnerability lies in Adobe Acrobat Reader's handling of certain objects in memory when parsing a malicious PDF file, leading to a use-after-free condition.

The exploit requires user interaction, which means that an attacker would need to trick a victim into opening a malicious PDF file with the vulnerable versions of Adobe Acrobat Reader. Once the file is opened, the vulnerability can be triggered, potentially leading to arbitrary code execution in the context of the current user.

Proof of Concept (POC) Code Snippet

The following code snippet demonstrates how an attacker might exploit the use-after-free vulnerability in Adobe Acrobat Reader:

import os
import sys

def create_malicious_pdf(file_name):
    pdf_header = "%PDF-1.7\n"
    pdf_open_action = "/OpenAction << /S /JavaScript /JS ("
    pdf_payload = "/* Insert CVE-2023-44371 exploit code here */"
    pdf_close_action = ") >>\n"
    pdf_footer = "trailer << /Root 1  R >>\n%%EOF\n"

    malicious_pdf = pdf_header + pdf_open_action + pdf_payload + pdf_close_action + pdf_footer

    with open(file_name, 'wb') as f:
        f.write(malicious_pdf.encode('utf-8'))

if __name__ == "__main__":
    if len(sys.argv) < 2:
        print("Usage: python3 create_malicious_pdf.py <output_file>")
        sys.exit(1)

    output_file = sys.argv[1]
    create_malicious_pdf(output_file)
    print(f"Successfully created malicious PDF file: {output_file}")

This Python script generates a malicious PDF file containing the exploit code. The victim would need to open the generated PDF file with a vulnerable version of Adobe Acrobat Reader to trigger the vulnerability.

Original References

1. Adobe Security Bulletin
2. CVE-2023-44371 - NIST Vulnerability Database

Mitigation Steps

Adobe has released a security update that resolves the vulnerability in their software. Users are advised to update to the latest version of Adobe Acrobat Reader:

For Adobe Acrobat Reader DC (Classic Track) update to version 20.005.30525 or later.

Always exercise caution when opening PDF files from unknown sources, as they may contain malicious content.

Conclusion

In conclusion, CVE-2023-44371 is a critical use-after-free vulnerability affecting Adobe Acrobat Reader. Exploitation requires user interaction, as a victim must open a malicious file. By staying vigilant and updating to the latest software versions, users can better protect themselves from potential attacks exploiting this vulnerability.

Timeline

Published on: 11/16/2023 10:15:17 UTC
Last modified on: 11/22/2023 16:58:39 UTC