CVE-2025-24103: Improved Validation of Symlinks Prevents Unauthorized access to Protected User Data

We are aware that our cybersecurity community plays a crucial role in making the systems safer. Today, we will be discussing CVE-2025-24103, a vulnerability that, if exploited, could allow an attacker to access sensitive user data on macOS systems. This vulnerability affected earlier versions of macOS, but it has been fixed in macOS Ventura 13.7.3, MacOS Sequoia 15.3, and macOS Sonoma 14.7.3.

The Vulnerability

CVE-2025-24103 is tied to insecure handling of symbolic links (symlinks) in some macOS applications. A symlink is a special kind of file that points to another file or folder in the file system. Symlinks are widely used by developers to create shortcuts, save space, and organize files. However, if not managed properly, symlinks can be abused by malicious actors to gain unauthorized access to sensitive information.

Exploit Details

Attackers exploiting CVE-2025-24103 could create malicious symlinks that link to protected files within a user's system, providing unauthorized access to personal data such as emails, photos, or documents. A successful exploit of this vulnerability would require the attacker to have access to the target's machine, either through previous exploitation or through physical access.

Here is an example of a vulnerable code snippet, which allows the symlink attack to take place

// Function to copy a file
void insecure_copy(const char *src, const char *dst) {
    // ... other code ...
    // Open source file
    int src_fd = open(src, O_RDONLY);

    // ... other code ...
    // Create new destination file with source permissions
    int dst_fd = open(dst, O_WRONLY | O_CREAT, src_stat.st_mode);

    // ... other code ... 
    // Copy data from source to destination
}

In this code snippet, an attacker could potentially replace src or dst with malicious symlinks, leading to unauthorized access to sensitive user data.

Solution

Fortunately, this issue has been addressed in the latest macOS versions listed earlier (i.e., macOS Ventura 13.7.3, macOS Sequoia 15.3, and macOS Sonoma 14.7.3) with improved symlink validation. Apple provided the following recommendation in their security advisory:

"An app may be able to access protected user data. This issue was addressed with improved validation of symlinks."

To protect your system from CVE-2025-24103, we recommend updating your macOS to the latest version. You can find additional guidance on updating macOS in this Apple support article.

Conclusion

CVE-2025-24103 highlights the importance of secure symlink handling. Developers should always validate and handle symlinks carefully to avoid unauthorized access to sensitive data. Users are advised to update their macOS systems to the latest version to stay protected against this vulnerability.

Timeline

Published on: 01/27/2025 22:15:15 UTC
Last modified on: 03/03/2025 22:45:38 UTC