CVE-2022-3257 in Mattermost
Summary
by MITRE • 09/23/2022
Mattermost version 7.1.x and earlier fails to sufficiently process a specifically crafted GIF file when it is uploaded while drafting a post, which allows authenticated users to cause resource exhaustion while processing the file, resulting in server-side Denial of Service.
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Analysis
by VulDB Data Team • 03/20/2023
The vulnerability identified as CVE-2022-3257 represents a critical server-side denial of service weakness within Mattermost versions 7.1.x and earlier. This flaw specifically manifests when authenticated users upload carefully crafted GIF files during the post drafting process, creating a scenario where the server becomes overwhelmed with resource consumption. The vulnerability exploits the application's insufficient validation and processing mechanisms for multimedia content, particularly affecting the image handling subsystem that processes GIF files. The issue stems from inadequate input sanitization and resource management during file processing, allowing malicious actors to consume excessive computational resources and memory allocation.
The technical implementation of this vulnerability involves the manipulation of GIF file structures to trigger specific processing behaviors within Mattermost's image handling pipeline. When a crafted GIF file is uploaded and processed, the server's resource allocation mechanisms become overwhelmed through repeated or excessive processing cycles. The flaw operates at the intersection of image parsing and resource management, where the application fails to implement proper bounds checking or resource limiting during GIF file analysis. This processing behavior aligns with CWE-400, which categorizes resource exhaustion vulnerabilities as those that allow attackers to consume system resources beyond normal operational limits. The vulnerability's impact is particularly severe because it affects authenticated users, meaning that an attacker with valid credentials can exploit this weakness without requiring additional privileges.
Operational implications of CVE-2022-3257 extend beyond simple service disruption to potentially compromise system availability and performance for legitimate users. The resource exhaustion occurs during the server-side processing phase when the application attempts to analyze and render the malicious GIF file, leading to increased CPU utilization, memory consumption, and potential process starvation. This vulnerability can be exploited repeatedly to maintain sustained denial of service conditions, making it particularly dangerous in environments where Mattermost serves as a critical communication platform. The attack vector is accessible through normal application usage patterns, specifically during the draft post creation workflow, making detection and prevention challenging. From an attack perspective, this vulnerability maps to ATT&CK technique T1499.004 which covers network denial of service attacks, and T1566.002 which involves spearphishing with social engineering elements.
Mitigation strategies for CVE-2022-3257 should prioritize immediate patching of affected Mattermost installations to version 7.2.0 or later, where the vulnerability has been addressed through improved input validation and resource management. Organizations should implement additional protective measures including file type validation, size limitations, and processing time constraints for multimedia uploads. Network monitoring should be enhanced to detect unusual resource consumption patterns during file upload operations, and rate limiting should be implemented to prevent rapid exploitation attempts. The implementation of automated file analysis systems that can identify potentially malicious GIF structures before processing would provide additional defense layers. Security teams should also consider implementing behavioral monitoring for abnormal resource utilization patterns and establish incident response procedures specifically tailored to handle denial of service conditions caused by multimedia file processing vulnerabilities.