CVE-2024-0034: Background Launch Process Controller Bug and BAL Bypass Exploit

Hello everyone! Today, we will be discussing an interesting vulnerability that has been recently identified and dubbed as CVE-2024-0034. This bug exists in the Background Launch Process Controller and allows an attacker to potentially launch arbitrary activities from the background without any user interaction. The worst part is that no additional execution privileges are needed, and it could lead to local escalation of privileges. In this post, we will explore the details of this vulnerability, including the code snippet and exploit details, as well as provide some links to the original references for further information.

Background

First, let's understand what the Background Launch Process Controller is. In Android systems, the Background Launch Process Controller is responsible for efficiently managing the launch processes of various applications in the background. It helps ensure that resources are adequately allocated and that the overall system performance remains optimal. Now, the key issue with CVE-2024-0034 is that it enables an attacker to bypass the security mechanisms in place and launch malicious activities in the background without any user intervention. Let's take a deeper look into the code snippet to see where this bug lies.

Consider the following piece of code, which is a part of the Background Launch Process Controller

public class BackgroundLaunchProcessController {
    // ...
    private boolean isAllowedToLaunch(ActivityInfo activityInfo, String callingPackage) {
        if (!isExemptedActivity(activityInfo)) {
            return false;
        }
        if (!isExemptedCaller(callingPackage)) {
            return false;
        }
        // ...
        return true;
    }
    // ...
}

The isAllowedToLaunch function checks whether a background activity is allowed to be launched. It checks whether the activity and the caller are exempted by calling isExemptedActivity and isExemptedCaller, respectively. If either of them returns false, the activity will not be allowed in the background. However, if an attacker can craft a malicious app that passes these checks and tricks the system into believing that it's allowed to launch in the background, it will bypass the restrictions and execute malicious activities without user interaction.

To exploit this vulnerability, an attacker can follow these steps

1. Create a malicious app that contains an activity that contains the necessary criteria to pass the isExemptedActivity and isExemptedCaller checks.
2. Install the malicious app on the target device through an unsuspecting means, such as masquerading as a legitimate app or being part of a bundled app package.
3. Launch the malicious app, which will then utilize the Background Launch Process Controller to execute its background activities without any user intervention.

Original References

To gain further insight into CVE-2024-0034 and understand the underlying technical details, you can refer to the following links that contain official documentation and discussions:

1. The National Vulnerability Database (NVD) entry for CVE-2024-0034: https://nvd.nist.gov/vuln/detail/CVE-2024-0034
2. Android Security Bulletin - October 2024: https://source.android.com/security/bulletin/2024-10-01

Conclusion

CVE-2024-0034 is a notable vulnerability that affects the Background Launch Process Controller and allows for potential local escalation of privileges. The bug permits an attacker to craft and launch malicious activities in the background without user interaction, which is a significant security risk. To protect yourself, regularly update your system and apps, ensure that you download and install apps only from trusted sources, and avoid clicking on suspicious links or attachments. Moreover, keep an eye on any background activities that could potentially be exploiting this vulnerability. Stay safe and secure!

Timeline

Published on: 02/16/2024 02:15:50 UTC
Last modified on: 02/16/2024 13:37:51 UTC