CVE-2023-2783 in Server
Summary
by MITRE • 06/16/2023
Mattermost Apps Framework fails to verify that a secret provided in the incoming webhook request allowing an attacker to modify the contents of the post sent by the Apps.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 06/16/2023
The Mattermost Apps Framework vulnerability CVE-2023-2783 represents a critical authentication flaw that undermines the security of webhook-based integrations within the Mattermost collaboration platform. This vulnerability specifically affects the Apps Framework's handling of incoming webhook requests where secret verification mechanisms are bypassed, allowing unauthorized modification of post contents. The flaw exists in the framework's validation logic that should normally authenticate webhook requests using predefined secrets before processing the incoming data. When this verification step is omitted or improperly implemented, malicious actors can craft specially crafted webhook requests that appear legitimate to the system while containing modified payload data. This creates a scenario where attackers can inject arbitrary content into Mattermost channels, potentially leading to misinformation dissemination, data corruption, or the execution of malicious commands through crafted post content.
The technical implementation of this vulnerability stems from inadequate input validation and authentication checks within the Apps Framework's webhook processing pipeline. According to CWE-347, this represents a weakness in authentication token validation where the system fails to properly verify the authenticity of incoming requests. The vulnerability manifests when the framework receives webhook data without performing the required secret verification that should act as a cryptographic check to ensure the request originates from a legitimate source. This flaw operates at the interface between external webhook triggers and internal post processing functions, where the framework should enforce strict authentication before accepting and publishing content. The missing verification step allows attackers to manipulate the request parameters while maintaining the appearance of legitimate webhook traffic, effectively bypassing the security controls that should protect against unauthorized content modification.
The operational impact of CVE-2023-2783 extends beyond simple content manipulation to potentially compromise the integrity and trustworthiness of communication channels within Mattermost environments. Attackers exploiting this vulnerability can inject malicious links, falsify system notifications, or disseminate misleading information to team members, undermining the platform's reliability as a secure communication channel. In enterprise settings where Mattermost serves as a critical collaboration tool for sensitive discussions, this vulnerability could enable social engineering attacks, data exfiltration attempts, or the disruption of business operations through forged notifications. The attack surface is particularly concerning given that webhook integrations are commonly used for automated notifications, CI/CD pipeline updates, and system monitoring alerts where the integrity of transmitted information is paramount. Organizations using Mattermost for compliance-sensitive environments may face regulatory violations or security breaches if this vulnerability is exploited to alter audit trails or operational communications.
Security mitigations for CVE-2023-2783 should focus on implementing proper secret verification mechanisms throughout the Apps Framework's webhook processing pipeline. Organizations should ensure that all incoming webhook requests undergo mandatory authentication checks using pre-shared secrets before any content processing occurs. The implementation should follow established security practices for webhook authentication, including cryptographic verification of request signatures and validation of request timestamps to prevent replay attacks. According to ATT&CK technique T1566.002, this vulnerability could enable initial access through webhook-based attack vectors, making proper authentication critical for preventing broader exploitation. System administrators should also implement monitoring for unusual webhook activity patterns and establish incident response procedures for detecting unauthorized content modifications. The framework should be updated to enforce secret validation at the earliest possible point in the request processing flow, ensuring that any request lacking proper authentication is rejected before any data processing occurs. Additionally, organizations should review their webhook configurations to ensure that only trusted sources are permitted to submit requests to the Mattermost platform, implementing network-level restrictions where possible to further reduce the attack surface.