CVE-2022-44519: Uncovering a Use-After-Free Vulnerability in Acrobat Reader DC

In this long read, we will discuss a recent vulnerability found in Adobe Acrobat Reader DC, a widely used PDF viewer application. The vulnerability, identified by the Common Vulnerabilities and Exposures (CVE) ID CVE-2022-44519, affects Acrobat Reader DC versions 22.001.20085 (and earlier), 20.005.3031x (and earlier), and 17.012.30205 (and earlier). This use-after-free vulnerability can potentially lead to the disclosure of sensitive memory data and can be exploited to bypass security mitigations such as Address Space Layout Randomization (ASLR). Exploiting this issue does require user interaction, as a victim must open a malicious file for the attack to be successful.

Use-After-Free Vulnerability Details

A use-after-free vulnerability occurs when a program continues to use a pointer after the memory it points to has been freed. This can lead to various types of unintended behavior, including crashes, data corruption, and potentially even code execution.

In the case of CVE-2022-44519, Acrobat Reader DC's handling of certain objects in a PDF file can trigger a use-after-free condition. The following code snippet demonstrates how this vulnerability can manifest:

// Simplified representation of the vulnerable code in Acrobat Reader DC.
void process_pdf_object(pdf_object *obj)
{
    if (obj->type == PDF_OBJECT_SPECIAL)
    {
        pdf_object *special_data = get_special_data(obj);
        free(obj);

        // Use-after-free occurs here if 'obj' is accessed after it has been freed.
        ...\

    }

    ...
}

By crafting a malicious PDF file that causes this use-after-free condition to occur, an attacker can potentially read sensitive memory data that was previously associated with the now-freed object. This can provide information about the memory layout of the process and help the attacker bypass ASLR, a key defense mechanism that randomizes the positions of data in memory to make exploitation more difficult.

For more information on this vulnerability, including the original disclosure, you can review the following references:

1. CVE Details: CVE-2022-44519
2. Adobe Security Bulletin: APSB22-26

Exploitation

To exploit CVE-2022-44519, an attacker must create a malicious PDF file that triggers the use-after-free condition in Acrobat Reader DC. The attacker could then distribute this file to potential victims via email or other means.

Once a victim opens the malicious PDF in a vulnerable version of Acrobat Reader DC, the use-after-free condition occurs. This can enable the attacker to read previously freed memory data, which could potentially contain sensitive information that aids in the bypassing of ASLR and other mitigations.

Mitigation

To protect against this vulnerability, Adobe has released security updates for affected Acrobat Reader DC versions. Users are advised to update their software to the latest versions, which are not susceptible to this use-after-free vulnerability:

Conclusion

CVE-2022-44519 is a significant vulnerability in Adobe Acrobat Reader DC that can lead to the exposure of sensitive memory data. As such, it is essential that users update their software to the latest versions to protect themselves from potential attacks. By staying informed about vulnerabilities like CVE-2022-44519 and promptly applying security updates when necessary, users can help safeguard their systems from exploits and maintain the highest level of security.

Timeline

Published on: 12/19/2024 00:15:06 UTC