CVE-2021-43782 in Tuleap Community Edition
Summary
by MITRE • 12/15/2021
Tuleap is a Libre and Open Source tool for end to end traceability of application and system developments. This is a follow up to GHSA-887w-pv2r-x8pm/CVE-2021-41276, the initial fix was incomplete. Tuleap does not sanitize properly the search filter built from the ldap_id attribute of a user during the daily synchronization. A malicious user could force accounts to be suspended or take over another account by forcing the update of the ldap_uid attribute. Note that the malicious user either need to have site administrator capability on the Tuleap instance or be an LDAP operator with the capability to create/modify account. The Tuleap instance needs to have the LDAP plugin activated and enabled for this issue to be exploitable. The following versions contain the fix: Tuleap Community Edition 13.2.99.83, Tuleap Enterprise Edition 13.1-6, and Tuleap Enterprise Edition 13.2-4.
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Analysis
by VulDB Data Team • 12/18/2021
CVE-2021-43782 represents a critical authentication and authorization vulnerability within Tuleap's LDAP synchronization mechanism that builds upon previously identified weaknesses. This vulnerability stems from insufficient input sanitization during the daily user synchronization process, specifically targeting the ldap_id attribute handling. The flaw allows malicious actors to manipulate user account attributes through crafted ldap_uid values, creating a pathway for account takeovers and unauthorized account suspensions. The vulnerability is particularly concerning as it requires minimal privileges to exploit, needing either administrative access or LDAP operator capabilities, making it a significant risk for organizations relying on Tuleap's integrated LDAP authentication systems.
The technical implementation of this vulnerability resides in the improper sanitization of user-provided data during the LDAP synchronization process. When Tuleap processes user accounts during daily synchronization, it fails to properly validate or sanitize the ldap_id attribute values that originate from LDAP directories. This oversight creates a direct injection vector where malicious users can manipulate the ldap_uid attribute to force unauthorized account modifications. The vulnerability operates at the application layer and specifically affects the identity management and user account synchronization components of Tuleap's architecture. According to CWE classification, this represents a weakness in input validation and data sanitization, specifically categorized under CWE-20 for improper input validation and CWE-79 for cross-site scripting vulnerabilities in the context of user attribute manipulation.
The operational impact of CVE-2021-43782 extends beyond simple account compromise, creating potential for broader system infiltration and unauthorized privilege escalation. An attacker exploiting this vulnerability can systematically suspend legitimate user accounts, effectively creating denial of service conditions while simultaneously gaining unauthorized access to target accounts. The vulnerability's exploitation requires only moderate privileges, as it can be leveraged by either site administrators or LDAP operators, making it particularly dangerous in environments where these roles are not properly restricted. This weakness directly violates the principle of least privilege and can be mapped to ATT&CK technique T1078 for valid accounts and T1531 for account access removal, as it enables unauthorized account takeover and suspension capabilities.
Organizations must implement immediate remediation measures to address this vulnerability, with the most effective solution being the upgrade to patched Tuleap versions including Community Edition 13.2.99.83 and Enterprise Editions 13.1-6 and 13.2-4. Additionally, administrators should conduct thorough access control reviews to ensure that LDAP operator privileges are properly restricted and that only authorized personnel have the capability to modify user accounts. Network monitoring should be enhanced to detect unusual account modification patterns during synchronization periods, while LDAP directory configurations should be reviewed to ensure proper attribute validation and sanitization. The vulnerability's remediation aligns with security best practices outlined in NIST SP 800-53 and ISO/IEC 27001 controls for access control and input validation, requiring organizations to implement robust sanitization procedures for all external data inputs, particularly those originating from directory services.