CVE-2023-49809 in Mattermost
Summary
by MITRE • 12/12/2023
Mattermost fails to handle a null request body in the /add endpoint, allowing a simple member to send a request with null request body to that endpoint and make it crash. After a few repetitions, the plugin is disabled.
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Analysis
by VulDB Data Team • 01/02/2024
The vulnerability identified as CVE-2023-49809 represents a critical input validation flaw within the Mattermost collaboration platform that specifically affects the /add endpoint functionality. This issue stems from the application's insufficient handling of null request bodies, creating a condition where authenticated users can deliberately exploit this weakness to cause service disruption. The vulnerability exists within the plugin architecture of Mattermost, where the system fails to properly validate incoming request data before processing it through the add endpoint. This oversight allows an attacker with basic member privileges to craft malicious requests containing null payloads that trigger an unhandled exception in the application's processing logic.
The technical implementation of this vulnerability demonstrates a classic lack of proper error handling and input sanitization that aligns with CWE-476, which specifically addresses null pointer dereference conditions in software systems. When a null request body is submitted to the /add endpoint, the application fails to implement defensive programming practices that would gracefully handle such malformed inputs. The system attempts to process the null payload without proper validation checks, leading to an application crash that manifests as a complete service disruption. This type of vulnerability falls under the category of denial of service conditions where the attacker can repeatedly exploit the flaw to maintain system instability.
The operational impact of CVE-2023-49809 extends beyond simple service disruption as it provides a pathway for persistent system degradation that can ultimately lead to complete plugin disablement. The vulnerability's exploitation pattern shows that repeated attempts to send null request bodies can cause the plugin to become disabled entirely, which represents a significant escalation from initial denial of service to potential complete system compromise. This vulnerability directly impacts the availability and reliability of Mattermost's plugin ecosystem, affecting collaboration workflows and potentially exposing organizations to extended periods of reduced functionality. The fact that this can be exploited by "simple members" rather than requiring elevated privileges makes it particularly concerning from a security perspective, as it demonstrates how internal users can create cascading failures within the platform.
From a cybersecurity framework perspective, this vulnerability maps to multiple ATT&CK techniques including T1499.004 for network denial of service and T1566.002 for phishing with malicious attachments, as it could be leveraged to create conditions that facilitate further attacks. The vulnerability's exploitation requires minimal technical skill and can be automated, making it attractive to threat actors seeking to disrupt collaboration environments. Organizations implementing Mattermost should consider this vulnerability as part of their broader security posture assessment, particularly in environments where plugin functionality is critical to business operations. The remediation approach should focus on implementing proper input validation, adding defensive programming practices, and ensuring that all endpoints properly handle null or malformed request bodies. This vulnerability highlights the importance of robust error handling mechanisms and input validation in enterprise collaboration platforms, as these systems often serve as critical communication infrastructure within organizations.
The long-term implications of this vulnerability suggest that similar issues may exist in other endpoints within the Mattermost platform's plugin architecture. Security teams should conduct comprehensive audits of all plugin endpoints to identify potential null pointer dereference conditions and other input validation weaknesses. This vulnerability serves as a reminder that even seemingly simple endpoints can create significant security risks when proper defensive programming practices are not implemented. The exploitation pattern indicates that the system's resilience against malformed inputs is insufficient, requiring immediate attention to prevent potential escalation to more serious compromise scenarios.