CVE-2023-28646 Explained : Impact and Mitigation

This CVE involves an issue in the Nextcloud Android app where the app lockout feature can be bypassed via third-party apps, potentially leading to unauthorized access to sensitive information.

Understanding CVE-2023-28646

The vulnerability identified as CVE-2023-28646 affects Nextcloud android, an app designed to interact with the Nextcloud home server ecosystem. Attackers with access to the unlocked physical device can exploit this vulnerability to bypass the app's pin/passcode protection via a third-party app. This could enable the attacker to view meta information such as sharer, sharees, and file activity.

What is CVE-2023-28646?

The CWE-287 and CWE-281 vulnerabilities involved in this CVE pertain to improper authentication and preservation of permissions, respectively. The CVSS v3.1 base score for this vulnerability is 4.4, indicating a medium severity issue. The attack complexity is high, requiring physical access, with low impact on availability, confidentiality, and integrity. User interaction is also required to exploit this vulnerability.

The Impact of CVE-2023-28646

The impact of CVE-2023-28646 can result in unauthorized access to sensitive information stored within the Nextcloud Android app. This breach in security could lead to potential privacy violations and compromise the confidentiality of user data.

Technical Details of CVE-2023-28646

The vulnerability arises due to improper authentication and preservation of permissions within the Nextcloud Android app. Below are further technical details regarding this CVE:

Vulnerability Description

The vulnerability allows attackers to bypass the app lockout feature of Nextcloud Android, granting them access to sensitive information on the device via third-party apps.

Affected Systems and Versions

The affected systems include Nextcloud android app versions greater than or equal to 3.7.0 and less than 3.24.1. These versions are confirmed to be vulnerable to the bypass of the app lockout security measure.

Exploitation Mechanism

Attackers exploit this vulnerability by utilizing third-party apps to circumvent the pin/passcode protection of the Nextcloud Android app, enabling unauthorized access to sensitive data stored within the app.

Mitigation and Prevention

To address and prevent the potential risks associated with CVE-2023-28646, consider the following mitigation strategies:

Immediate Steps to Take

Users should update their Nextcloud Android app to version 3.24.1 or later to mitigate the vulnerability.
Avoid granting unnecessary permissions to third-party apps to minimize the risk of unauthorized access.

Long-Term Security Practices

Educate users on security best practices, such as using strong, unique passcodes and avoiding unauthorized app installations.
Regularly monitor and review app permissions to ensure only essential permissions are granted.

Patching and Updates

Stay informed about security advisories and updates released by Nextcloud to address known vulnerabilities promptly.
Implement a regular update schedule for all applications to ensure the latest security patches are applied.