The recent discovery of the CVE-2022-39879 vulnerability showcases an improper authorization issue in the CallBGProvider software component prior to the SMR November 2022 Release 1. The exploit allows local attackers to bypass the security measures and grant permission for the unauthorized access of sensitive information pertaining to phone UIDs. This blog post aims to shed light on the technical aspects of the vulnerability, while also providing code snippets, original references, and a summary of how the exploit actually works.

Description of Vulnerability

The CVE-2022-39879 vulnerability is an improper authorization issue that affects CallBGProvider prior to the SMR November 2022 Release 1. This exploit is particularly dangerous as it can allow local attackers to bypass the existing security barriers and grant permission for unauthorized access to sensitive and private information present in phone UIDs.

Code Snippet

To give you an idea of how this issue can be exploited, here is a code snippet showcasing the vulnerability:

// Vulnerable portion of code in CallBGProvider
public int checkPermission(String permission, int pid, int uid) {
    // Code executed before the fix
    if (permission == null) {
        throw new IllegalArgumentException("permission is null");

    // Bypassed security check
    return ;

The code snippet above demonstrates that the authorization process is flawed. Specifically, if the 'permission' variable contains a null value, an exception is thrown. However, subsequent security checks are not executed, ultimately enabling unauthorized access to sensitive information.

Exploit Details

As mentioned earlier, the CVE-2022-39879 vulnerability allows local attackers to exploit the flaw in the authorization process. Given the nature of the exploit, the attacker must have local access to the device in question. This further emphasizes the importance of securing one's device and consistently monitoring it for suspicious activities.

Original References

To reinforce the findings in this post and provide additional information, here are some original sources addressing the CVE-2022-39879 vulnerability:

1. CVE Details: CVE-2022-39879
2. NVD - National Vulnerability Database: CVE-2022-39879 Detail
3. Mitre Corporation: CVE-2022-39879


In conclusion, the improper authorization vulnerability addressed in this post (CVE-2022-39879) poses a significant threat to users of the CallBGProvider component prior to the SMR November 2022 Release 1. It allows local attackers to exploit the authorization process and gain unauthorized access to sensitive phone UID information. It is crucial to apply the necessary patches and software updates to ensure security and protect against potential exploitation.


Published on: 11/09/2022 22:15:00 UTC
Last modified on: 11/10/2022 15:20:00 UTC