CVE-2020-14452 in Mattermost Server
Summary
by MITRE
An issue was discovered in Mattermost Server before 5.21.0. mmctl allows directory traversal via HTTP, aka MMSA-2020-0014.
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Analysis
by VulDB Data Team • 10/25/2020
The vulnerability identified as CVE-2020-14452 represents a critical directory traversal flaw within the Mattermost Server platform prior to version 5.21.0. This security weakness specifically affects the mmctl command-line tool which is used for administrative operations within Mattermost environments. The issue stems from inadequate input validation and path handling mechanisms that allow malicious actors to exploit HTTP requests to access arbitrary files on the server filesystem. The vulnerability is categorized under CWE-22, which specifically addresses improper limitation of a pathname to a restricted directory, commonly known as path traversal attacks. This weakness enables attackers to bypass normal access controls and potentially gain unauthorized access to sensitive system resources.
The technical implementation of this vulnerability occurs when mmctl processes HTTP requests without proper sanitization of user-supplied input parameters. Attackers can manipulate request parameters to traverse directories beyond the intended scope, allowing them to read files that should remain restricted. This flaw operates at the application layer and can be exploited through HTTP-based communication channels, making it particularly dangerous in networked environments where Mattermost servers are accessible to external parties. The vulnerability essentially allows an attacker to craft malicious HTTP requests that can navigate through the server's file system hierarchy, potentially accessing configuration files, database credentials, or other sensitive data stored on the system.
The operational impact of this vulnerability extends beyond simple unauthorized file access, as it can lead to complete system compromise when combined with other attack vectors. An attacker who successfully exploits this directory traversal vulnerability can potentially extract sensitive information such as database connection strings, API keys, or application configuration files that contain critical system parameters. The implications are particularly severe in enterprise environments where Mattermost serves as a communication platform for internal business operations, as this could lead to data breaches, intellectual property theft, or disruption of critical communication channels. This vulnerability aligns with ATT&CK technique T1083, which covers discovering file and directory permissions, and T1566, which addresses credential access through various means including path traversal attacks.
Organizations using Mattermost Server versions prior to 5.21.0 should immediately implement mitigations to protect their systems from exploitation. The primary recommended action is to upgrade to Mattermost Server version 5.21.0 or later, which includes patched code that properly validates and sanitizes input parameters before processing HTTP requests. Additionally, network administrators should implement strict access controls and firewall rules to limit exposure of mmctl endpoints to trusted networks only. Input validation measures should be strengthened at the application level to ensure that all user-supplied parameters are properly sanitized before being processed. Organizations should also conduct comprehensive security audits of their Mattermost installations to identify and remediate any other potential vulnerabilities that could be exploited in conjunction with this directory traversal flaw. The implementation of web application firewalls and intrusion detection systems can provide additional layers of protection against exploitation attempts targeting this specific vulnerability.