CVE-2011-1821 in Tivoli Directory Server
Summary
by MITRE
IBM Tivoli Directory Server (TDS) 5.2 before 5.2.0.5-TIV-ITDS-IF0010 on Windows allows remote authenticated users to cause a denial of service (daemon hang) via a cn=changelog search.
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Analysis
by VulDB Data Team • 05/06/2017
IBM Tivoli Directory Server version 5.2 before 5.2.0.5-TIV-ITDS-IF0010 on Windows platforms contains a critical vulnerability that enables remote authenticated attackers to induce a denial of service condition through a specifically crafted cn=changelog search operation. This vulnerability resides in the directory server's handling of search requests targeting the changelog attribute, which is a fundamental component used for tracking modifications within the directory service. The flaw manifests when the server processes a search operation with the cn=changelog parameter, causing the daemon process to become unresponsive or hang, effectively rendering the directory service unavailable to legitimate users. The vulnerability classification aligns with CWE-400, which addresses unspecified denial of service conditions in software systems. The attack vector requires only authenticated access to the directory service, making it particularly concerning as it can be exploited by users who have legitimate credentials but may not necessarily require such elevated privileges. This weakness directly impacts the availability aspect of the CIA triad, as it compromises the system's ability to provide continuous service to authorized users. The operational impact extends beyond simple service interruption, as directory services often serve as foundational components for authentication, authorization, and identity management across enterprise networks, potentially affecting multiple dependent systems and applications. The vulnerability represents a classic example of improper input validation and resource handling, where the server fails to properly manage the processing of changelog search requests, leading to resource exhaustion or thread blocking conditions. From an adversarial perspective, this vulnerability fits within the ATT&CK framework under the T1499.004 technique for Network Denial of Service, as it specifically targets network services to disrupt availability. The affected IBM Tivoli Directory Server version demonstrates a failure in proper error handling and request processing mechanisms, where the server does not adequately validate or sanitize search parameters before attempting to process them. This particular flaw affects Windows deployments of the TDS 5.2.x series, indicating a platform-specific implementation issue that may stem from differences in how Windows handles certain search operations compared to other operating systems. The vulnerability's exploitability requires minimal technical expertise, as it only requires authentication to the directory service and the ability to construct a specific search query. Organizations using this version of IBM Tivoli Directory Server should immediately apply the patch referenced in the IBM advisory to prevent potential exploitation. The remediation process involves upgrading to IBM Tivoli Directory Server 5.2.0.5-TIV-ITDS-IF0010 or later versions, which contain the necessary fixes to properly handle changelog search operations and prevent daemon hanging conditions. Security administrators should also implement monitoring solutions to detect unusual search patterns that might indicate exploitation attempts, particularly around changelog access operations. The vulnerability highlights the importance of thorough testing of directory service components under various load and input conditions, as well as the necessity of maintaining up-to-date security patches for enterprise directory services. This issue also underscores the critical need for proper access controls and network segmentation to limit exposure of directory services to potential attackers, as the vulnerability requires authentication to exploit but can cause widespread service disruption once successfully executed. Organizations should conduct comprehensive vulnerability assessments to identify other potentially affected systems running older versions of IBM Tivoli Directory Server or similar directory services that may exhibit similar weaknesses in their changelog handling mechanisms.