CVE-2024-41879: Critical Out-of-bounds Write Vulnerability in Acrobat Reader Versions 127..2651.105 and Earlier, Potentially Resulting in Arbitrary Code Execution

An important vulnerability, labelled as CVE-2024-41879, has been discovered affecting Acrobat Reader versions 127..2651.105 and earlier. This critical issue results from an out-of-bounds write vulnerability that, if exploited, could enable attackers to execute arbitrary code in the context of the victim's user account. It is important to understand that successful exploitation of this issue requires user interaction, meaning victims need to open a malicious file for the exploit to take place.

Technical Details

The vulnerability arises from the vulnerable version of Acrobat Reader improperly handling certain objects in memory when parsing a malicious PDF file. The incorrect memory handling causes an out-of-bounds write, which may allow an attacker who crafted the malicious file to perform arbitrary code execution on the victim's system.

Below is a brief pseudo-code snippet demonstrating the potential vulnerable code in Acrobat Reader

// Process the PDF object
void process_pdf_object(obj_type *obj) {
    int index;
    char data[BUFFER_SIZE];

    // Get the index from the object
    index = get_index(obj);

    // Perform an out-of-bounds write, leading to the exploit
    if(index >= ARRAY_SIZE) {
        printf("Error: Index out of bounds.\n");
        return;
    }

    // Write data to the buffer, enabling attackers to execute arbitrary code
    data[index] = obj->value;
}

In the code snippet above, the get_index() function returns an index that is not properly validated before being used. The data may be written to an arbitrary location (data[index]), potentially allowing an attacker to execute arbitrary code on the victim's system.

To exploit this vulnerability, an attacker would need to

1. Craft a malicious PDF file containing specially designed objects that exploit the out-of-bounds write vulnerability.

Persuade the victim to open the malicious PDF file using a vulnerable Acrobat Reader version.

4. The vulnerability would then be triggered, potentially allowing the attacker to execute arbitrary code on the victim's system with the privileges of the logged-in user.

The requirement of user interaction to open the malicious file reduces the scope of this vulnerability but does not eliminate the risk entirely. Users should remain vigilant and avoid opening PDF files from untrusted sources.

Available Patches and Mitigations

Adobe has released a security update to address this vulnerability, and users are advised to update their Acrobat Reader software to the latest version as soon as possible. You can find the relevant security update for your system on the Adobe Security Bulletins and Advisories page.

Additionally, users should use caution when opening PDF files from unknown sources, as user interaction is required for successful exploitation of this vulnerability.

Original References

Further information and details regarding this vulnerability can be found in the following original references:

- CVE-2024-41879 - NVD
- Adobe Security Bulletin

Users are strongly encouraged to keep their software up-to-date and follow secure practices when handling files from unknown sources.

Timeline

Published on: 08/26/2024 12:15:05 UTC
Last modified on: 08/26/2024 12:47:20 UTC