CVE-2022-20456: Possible Failure to Persist Permissions Settings in AutomaticZenRule.java due to Resource Exhaustion, Leading to Local Escalation of Privilege

The vulnerability CVE-2022-20456 has been identified to affect AutomaticZenRule.java in Android-10, Android-11, Android-12, Android-12L, and Android-13. The vulnerability enables a possible failure to persist permissions settings because of resource exhaustion, thereby leading to a local escalation of privilege. It is crucial to note that user interaction is not necessary to exploit this vulnerability, and the attacker does not need additional execution privileges. In this post, we will discuss the details of this vulnerability, share code snippets to clarify the issue, and provide reference links for further reading.

Code Snippet

AutomaticZenRule.java is meant to handle rule settings in the application for controlling permissions. The vulnerability is caused as a result of a lack of proper handling of resource exhaustion. Here's an example of a code snippet in AutomaticZenRule.java:

public class AutomaticZenRule {

  public AutomaticZenRule(Uri uri) {
    ...
    setConditionId(conditionId);
    ...
    setConfiguration(configuration);
    ...
    setInterruptionFilter(interruptionFilter);
  }

  public void update(AutomaticZenRule newRule) {
    ...
    setConditionId(conditionId);
    ...
    setConfiguration(configuration);
    ...
    setInterruptionFilter(interruptionFilter);
  }

  ...

}

The vulnerability occurs because the update method, which is meant to change the permissions settings, may fail to do so due to limited system resources. This could lead to an incorrect state of the application, where the permissions are not updated as expected.

Exploit Details

As mentioned earlier, this vulnerability has the potential to escalate local privileges without requiring user interaction or any additional execution privileges. Attackers may exploit this issue by causing resource exhaustion on the target device and then attempting to update permissions settings in the application. Due to the vulnerability, the update would fail, leaving the application in an incorrect state and the attacker with escalated privileges.

Original References and Further Reading

For additional information and details on this vulnerability, you can refer to the following original references:

1. Android Security Bulletin: https://source.android.com/security/bulletin
2. Android Vulnerability Details: https://source.android.com/security/bulletin/2022-02-01

Mitigation

As of now, the Android Security team has acknowledged this vulnerability and recommends following the latest Android Security Bulletins and updates. It is advised to keep your Android devices updated with the latest patches and security fixes to protect against such vulnerabilities.

Conclusion

CVE-2022-20456 is a critical vulnerability that affects the AutomaticZenRule.java file in various Android versions. It highlights the importance of properly handling resource exhaustion and ensuring the correct state of the application. Developers must ensure that their applications are secured against such vulnerabilities through code reviews, proper management of system resources, and regular updates. Users, on the other hand, should stay vigilant about their device's security by keeping it up-to-date and following the latest security bulletins.

Timeline

Published on: 01/26/2023 21:15:00 UTC
Last modified on: 02/01/2023 15:19:00 UTC