CVE-2023-40125: Undocumented Vulnerability Found in ApnEditor.java that Allows Unauthorized Guest Users to Modify APN Settings

A new, critical vulnerability has been discovered in the Android operating system that could allow a local attacker to gain unauthorized access to change the Access Point Name (APN) settings on a device. This newly discovered vulnerability has been assigned the Common Vulnerabilities and Exposures (CVE) identifier CVE-2023-40125.

The vulnerability is located in the onCreate function of the ApnEditor.java file. Due to a permission bypass issue, a Guest user could potentially modify the APN settings without the need for additional execution privileges. Furthermore, user interaction is not required for this exploit to be successful, making it even more dangerous. In the following sections, we will cover the vulnerability in detail, provide code snippets, and discuss the potential risks and mitigations.

Vulnerability Details

In the Android Open Source Project (AOSP), the ApnEditor.java file is responsible for handling APN settings, which allow mobile devices to connect to the internet through cellular networks. The onCreate function in this file is designed to check for certain permissions before making modifications to the APN settings. Unfortunately, due to a permission bypass issue, this security check can be bypassed, leaving the APN settings potentially exposed to unauthorized access.

The following code snippet from the ApnEditor.java file showcases the permission check that is not working as intended:

@Override
protected void onCreate(Bundle icicle) {
    super.onCreate(icicle);
    
    // Check for permissions
    if (!UserManager.get(this).hasUserRestriction(UserManager.DISALLOW_CONFIG_MOBILE_NETWORKS)) {
        setEnablednessOfPreferences();
        return;
    }

    // Rest of the code
}

Exploit

Due to the permission bypass, an attacker can potentially access and modify the APN settings without obtaining the necessary DISALLOW_CONFIG_MOBILE_NETWORKS permission from the UserManager. Since user interaction is not needed for the exploitation, a malicious application or script could potentially make changes to the APN settings without the user's knowledge or consent. This could lead to a local escalation of privilege attack, causing disruption on the device's network connectivity.

For detailed technical information and a proof-of-concept exploit, kindly refer to the original advisory at:

* CVE-2023-40125 - Original Advisory

Impact

The potential risks of this vulnerability include unauthorized access to network settings modification, which can disrupt the device's internet connectivity, cause security breaches, or provide avenues for further malicious activities. Devices running the Android operating system are at risk, and it is crucial for developers and users alike to be aware of this vulnerability.

Mitigation

To mitigate the risk associated with CVE-2023-40125, developers should apply the following patch to fix the permission bypass in the ApnEditor.java file:

@Override
protected void onCreate(Bundle icicle) {
    super.onCreate(icicle);
    
    // Check for permissions
-   if (!UserManager.get(this).hasUserRestriction(UserManager.DISALLOW_CONFIG_MOBILE_NETWORKS)) {
+   if (UserManager.get(this).hasUserRestriction(UserManager.DISALLOW_CONFIG_MOBILE_NETWORKS)) {
        setEnablednessOfPreferences();
        return;
    }

    // Rest of the code
}

In addition to applying the patch, users should ensure that they only install applications from trusted sources and follow good security practices to keep their devices safe.

Conclusion

The discovery of CVE-2023-40125 demonstrates how even widely used projects like the Android operating system can contain vulnerabilities, leading to potential security risks. By staying informed about such vulnerabilities and promptly addressing them, developers and users can work together to create a safer digital environment for all.

Remember to visit the original advisory link for more information and keep your devices up to date with the latest security patches:

* CVE-2023-40125 - Original Advisory

Timeline

Published on: 10/27/2023 21:15:08 UTC
Last modified on: 10/30/2023 17:13:55 UTC