CVE-2018-21265 in Mattermost Desktop App
Summary
by MITRE
An issue was discovered in Mattermost Desktop App before 4.0.0. It mishandled the Same Origin Policy for setPermissionRequestHandler (e.g., video, audio, and notifications).
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Analysis
by VulDB Data Team • 10/25/2020
The vulnerability identified as CVE-2018-21265 represents a critical security flaw in the Mattermost Desktop Application prior to version 4.0.0, specifically concerning the improper handling of the Same Origin Policy within the setPermissionRequestHandler functionality. This issue exposes the application to potential privilege escalation and unauthorized access risks by failing to properly enforce origin-based security restrictions that should govern access to sensitive system resources such as camera, microphone, and notification permissions. The flaw exists in the desktop application's implementation of Electron framework's permission handling mechanisms, where the application does not adequately validate the origin of permission requests before granting access to system resources.
The technical implementation of this vulnerability stems from the application's failure to properly implement the Same Origin Policy, which is a fundamental security principle that prevents web content from accessing resources from different origins without proper authorization. In the context of desktop applications built on Electron, this policy should ensure that only trusted origins can request access to sensitive system capabilities. However, the Mattermost Desktop App's setPermissionRequestHandler implementation allowed malicious actors to exploit this weakness by crafting requests that bypassed normal origin validation checks. This misconfiguration creates a pathway for attackers to potentially gain unauthorized access to system resources that should be restricted to legitimate application functionality.
The operational impact of this vulnerability extends beyond simple privilege escalation as it fundamentally undermines the security boundaries of the desktop application. An attacker could potentially leverage this flaw to gain unauthorized access to a user's camera or microphone, or to send unsolicited notifications to the user's desktop environment. The vulnerability is particularly concerning because it affects the desktop application's core security model, potentially allowing attackers to execute malicious code or perform surveillance activities without user consent. This type of flaw directly impacts the application's ability to maintain user privacy and system integrity, creating potential vectors for data exfiltration, surveillance, or further attack escalation.
Security practitioners should note that this vulnerability aligns with CWE-345 Insufficient Verification of Data Authenticity, which addresses the lack of proper validation mechanisms for data sources. The issue also maps to ATT&CK technique T1059.001 Command and Scripting Interpreter: PowerShell, as attackers could potentially use similar privilege escalation techniques to gain unauthorized access. Organizations should implement immediate mitigation strategies including updating to Mattermost Desktop App version 4.0.0 or later, where the vulnerability has been addressed through proper implementation of origin validation. Additionally, security teams should conduct thorough assessments of other Electron-based applications to identify similar implementations of setPermissionRequestHandler that may exhibit similar vulnerabilities, ensuring comprehensive protection across all desktop applications that handle system permissions.