CVE-2022-23125: Netatalk Remote Code Execution Vulnerability Exploitation and Patches

In this post, we will examine the recent discovery CVE-2022-23125, a critical vulnerability that affects Netatalk installations, which could allow remote attackers to execute arbitrary code. This vulnerability has an assigned ID ZDI-CAN-15869 and poses a significant threat to systems using Netatalk due to the potential for exploitation without requiring authentication.

The Specific Flaw

CVE-2022-23125 concerns a flaw within the copyapplfile function in Netatalk. The vulnerability arises when the function parses the len element and doesn't properly validate the length of the user-supplied data before copying it to a fixed-length stack-based buffer. Attackers can leverage this vulnerability to execute code with root privileges, thus gaining access to the system.

Here's a simple example demonstrating the issue within the copyapplfile function

/* copyapplfile function */

void copyapplfile(char *src, char *dst, size_t len)
{
    char buffer[1024];

    // ... some code ...

    memcpy(buffer, src, len); // <-- Here's the problem, len is not checked!

    // ... some code ...
}

As shown above, the memcpy function does not validate the value of the len variable before copying the user-supplied data to the buffer.

Exploit Details

By exploiting this vulnerability, an attacker can send a specially crafted packet with a malicious len value. This could lead to a buffer overflow, allowing the attacker to execute any code with root privileges. Here is the process:

Original References

- The CVE-2022-23125 vulnerability was initially reported by the Zero Day Initiative: ZDI-CAN-15869
- The official CVE record: CVE-2022-23125

Mitigation and Patches

It is crucial to apply any available patches or updates from your Netatalk provider to protect your system from this vulnerability. The issue can be addressed by modifying the copyapplfile function in the following way:

/* Updated copyapplfile function */

void copyapplfile(char *src, char *dst, size_t len)
{
    char buffer[1024];

    // Add proper validation for len
    if (len > sizeof(buffer)){
        // Log the error
        return;
    }

    // ... some code ...

    memcpy(buffer, src, len);

    // ... some code ...
}

To stay secure, it is essential to keep your software updated continuously and follow best practices for system design and implementation. This will help ensure that your organization avoids any potential exploits related to found vulnerabilities like CVE-2022-23125.

Timeline

Published on: 03/28/2023 19:15:00 UTC
Last modified on: 04/03/2023 18:19:00 UTC