CVE-2023-3590 in Server
Summary
by MITRE • 07/17/2023
Mattermost fails to delete card attachments in Boards, allowing an attacker to access deleted attachments.
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Analysis
by VulDB Data Team • 08/06/2023
The vulnerability described in CVE-2023-3590 represents a critical data retention issue within the Mattermost collaboration platform, specifically affecting the Boards application component. This flaw manifests when users delete cards containing attachments within the Boards interface, yet the system fails to properly remove the associated file attachments from the underlying storage infrastructure. The vulnerability exposes sensitive data that should have been permanently deleted, creating a persistent security risk for organizations relying on Mattermost for secure communication and document management. This issue directly impacts the principle of data minimization and proper data lifecycle management that organizations must maintain to protect confidential information.
The technical implementation flaw stems from inadequate synchronization between the user interface operations and backend data deletion processes. When a user deletes a card in Mattermost Boards, the system correctly removes the card metadata from the database but fails to execute the corresponding file system cleanup operations for attachments. This represents a classic case of incomplete data removal, where the logical deletion of records does not translate to physical deletion of associated files. The vulnerability is classified under CWE-200 as "Information Exposure" and potentially CWE-532 as "Insertion of Sensitive Information into Log File" if the deleted files remain accessible through alternative pathways. From an attack perspective, this creates a data leak scenario where previously deleted sensitive documents, images, or files can still be accessed by unauthorized parties who gain access to the system or exploit the vulnerability.
The operational impact of this vulnerability extends beyond simple data exposure to encompass broader security governance concerns. Organizations using Mattermost Boards for handling confidential communications, project documentation, or compliance-sensitive materials face significant risks when deleted attachments remain accessible. Attackers could potentially exploit this vulnerability to recover deleted files containing intellectual property, personal data, or proprietary information, leading to data breaches that may violate regulations such as GDPR, HIPAA, or SOX compliance requirements. The vulnerability also impacts audit trails and forensic investigations, as deleted content appears to be permanently removed but actually persists in the system. This creates false confidence in data deletion practices and undermines the security posture of organizations relying on Mattermost for secure collaboration environments.
Mitigation strategies for CVE-2023-3590 should focus on immediate patch deployment from Mattermost, as the vulnerability requires core application functionality changes to address the improper deletion logic. Organizations should implement additional monitoring for file access patterns and establish automated cleanup procedures for deleted content. Network segmentation and access controls should be reinforced to limit exposure of sensitive data even when such vulnerabilities exist. Security teams should conduct comprehensive audits of file retention policies and ensure proper data lifecycle management procedures are in place. The ATT&CK framework categorizes this vulnerability under T1485 "Data Destruction" and T1567 "Exfiltration Over Web Service" as attackers could potentially leverage this to access deleted sensitive information, while T1078 "Valid Accounts" may be relevant if attackers gain access through compromised user credentials to exploit the vulnerability. Organizations should also consider implementing data loss prevention tools and regular security assessments to identify similar logical flaws in their collaboration platforms and ensure proper implementation of data deletion processes that align with industry security standards and regulatory requirements.