CVE-2022-24751 in Zulip
Summary
by MITRE • 03/16/2022
Zulip is an open source group chat application. Starting with version 4.0 and prior to version 4.11, Zulip is vulnerable to a race condition during account deactivation, where a simultaneous access by the user being deactivated may, in rare cases, allow continued access by the deactivated user. A patch is available in version 4.11 on the 4.x branch and version 5.0-rc1 on the 5.x branch. Upgrading to a fixed version will, as a side effect, deactivate any cached sessions that may have been leaked through this bug. There are currently no known workarounds.
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Analysis
by VulDB Data Team • 03/19/2022
The vulnerability identified as CVE-2022-24751 affects Zulip, an open source group chat application that serves as a collaborative communication platform for teams and organizations. This security flaw manifests as a race condition during the account deactivation process, representing a critical weakness in the application's session management and access control mechanisms. The vulnerability specifically impacts versions 4.0 through 4.10 of the software, creating a window of opportunity where concurrent user activities can exploit timing discrepancies in the deactivation workflow.
The technical flaw stems from improper synchronization mechanisms during account deactivation operations, where the system fails to adequately prevent concurrent access attempts from users whose accounts are in the process of being deactivated. This race condition allows for a temporal gap between when an account is marked for deactivation and when all active sessions are properly terminated, potentially enabling the deactivated user to maintain access to the system. The vulnerability operates at the intersection of concurrent programming errors and session management protocols, creating a scenario where multiple threads or processes can interfere with each other's operations during critical access control transitions.
From an operational perspective, this vulnerability presents significant security implications for organizations relying on Zulip for collaborative work environments. The potential for continued unauthorized access by deactivated users could lead to data breaches, information disclosure, and privilege escalation scenarios within the communication platform. The rarity of occurrence does not diminish the severity of potential impact, as even infrequent exploitation could provide attackers with extended access windows to sensitive organizational communications and data. The vulnerability affects the fundamental security principle of least privilege, where deactivated accounts should immediately lose all access rights to the system.
The mitigation strategy involves upgrading to version 4.11 on the 4.x branch or version 5.0-rc1 on the 5.x branch, which contain the necessary patches to address the race condition. Notably, the patch implementation includes an automatic cleanup mechanism that deactivates any cached sessions that may have been leaked through this vulnerability, providing an additional layer of security hardening. This remediation approach aligns with industry best practices for addressing race conditions in concurrent systems and demonstrates the importance of proper synchronization mechanisms in security-critical applications. Organizations should prioritize this upgrade to ensure complete protection against potential exploitation of this vulnerability.
This vulnerability maps to CWE-362, which specifically addresses race conditions in software systems, and relates to ATT&CK technique T1078.004 for valid accounts, as it allows continued access through compromised session management rather than direct credential theft. The issue highlights the importance of implementing proper locking mechanisms and atomic operations in security-critical components, particularly those handling user access control and session termination processes. The vulnerability underscores the need for comprehensive testing of concurrent access scenarios and proper handling of edge cases in authentication and authorization workflows within collaborative software platforms.