CVE-2019-20850 in Mattermost Mobile App
Summary
by MITRE
An issue was discovered in Mattermost Mobile Apps before 1.26.0. A view cache can persist on a device after a logout.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 10/25/2020
This vulnerability exists in the Mattermost mobile applications where an improper session management flaw allows cached view data to persist on devices even after users have logged out. The issue affects versions prior to 1.26.0 and represents a significant security concern for mobile device security. The vulnerability stems from inadequate clearing of application cache and temporary storage mechanisms during the logout process, creating a potential attack vector for unauthorized access to previously accessed data.
The technical flaw manifests as a failure in the application's memory management and cache invalidation procedures. When users log out of the Mattermost mobile application, the system should immediately purge all cached views, temporary files, and session data from the device's local storage. However, the application fails to properly execute this cleanup process, leaving sensitive information accessible through the cached view mechanisms. This behavior violates fundamental security principles of proper session termination and data sanitization, creating a persistent exposure window where unauthorized parties could potentially access previously viewed content.
The operational impact of this vulnerability extends beyond simple data exposure to encompass potential privilege escalation and information disclosure risks. An attacker with physical access to a logged-out device could potentially retrieve cached views containing sensitive messages, user information, or other confidential data that was previously accessible within the application. This vulnerability directly impacts the confidentiality and integrity of communications within the Mattermost platform, particularly concerning mobile device security and the principle of least privilege. The persistence of cached data creates a window of opportunity for unauthorized access that could be exploited in various scenarios including lost or stolen devices, insider threats, or compromised physical access situations.
This vulnerability aligns with CWE-200 (Information Exposure) and CWE-359 (Improperly Protected Stored Data) categories, representing a failure in proper data protection mechanisms during session termination. The issue also maps to ATT&CK technique T1531 (Account Access Removal) and T1552.001 (Unsecured Credentials) in the context of mobile application security. Organizations using Mattermost mobile applications should immediately implement patch management procedures to upgrade to version 1.26.0 or later, where the cache clearing mechanism has been properly implemented. Additional mitigations include implementing device encryption policies, configuring automatic lock timeouts, and establishing clear security guidelines for mobile device usage. Regular security assessments of mobile application cache management and session handling should be conducted to prevent similar vulnerabilities from emerging in the future.