CVE-2009-5073 in Tivoli Directory Server
Summary
by MITRE
IBM Tivoli Directory Server (TDS) 6.0 before 6.0.0.59 (aka 6.0.0.8-TIV-ITDS-IF0001) allows remote authenticated users to cause a denial of service (infinite loop and daemon hang) by adding a nested group that contains the Distinguished Name (DN) of its parent entry.
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Analysis
by VulDB Data Team • 01/25/2018
The vulnerability identified as CVE-2009-5073 affects IBM Tivoli Directory Server version 6.0 before 6.0.0.59, representing a critical denial of service weakness that can be exploited by authenticated remote attackers. This issue specifically targets the directory server's handling of nested group structures within its directory service implementation. The flaw manifests when a user with appropriate authentication credentials attempts to create or modify a group entry that contains a Distinguished Name reference to its own parent entry, creating a circular reference that the server cannot properly process.
The technical root cause of this vulnerability lies in the insufficient validation and recursive checking mechanisms within the Tivoli Directory Server's group membership processing logic. When a nested group structure is created where a group references its own parent group through the Distinguished Name field, the server's internal algorithms enter into an infinite loop during processing. This occurs because the server fails to detect the circular dependency between parent and child group entries, leading to a daemon hang where the process becomes unresponsive and cannot handle additional requests. The vulnerability is classified under CWE-838 as insufficient input validation, specifically concerning the improper handling of recursive data structures.
The operational impact of this vulnerability extends beyond simple service disruption, as it can effectively render the entire directory service unavailable to legitimate users. In enterprise environments where Tivoli Directory Server serves as a critical component for authentication and authorization services, such a denial of service condition can cascade into broader system failures. The infinite loop consumes system resources including CPU cycles and memory, potentially leading to system instability and requiring manual intervention to restart the affected services. This vulnerability particularly affects organizations that rely heavily on nested group structures for access control policies, as the attack can be executed through normal administrative operations without requiring special privileges beyond authentication.
Organizations should implement immediate mitigations including applying the vendor-provided patch release 6.0.0.59 or higher, which contains the necessary code fixes to properly detect and reject circular group references. Additionally, administrators should implement monitoring solutions to detect unusual resource consumption patterns that may indicate exploitation attempts. The vulnerability aligns with ATT&CK technique T1499.004 for denial of service by resource consumption, and organizations should consider implementing access controls that limit the ability to create nested group structures to reduce the attack surface. Network segmentation and intrusion detection systems can help identify potential exploitation attempts by monitoring for unusual LDAP operations that create circular group references. Regular security assessments and vulnerability scanning should be conducted to ensure that all directory server components remain patched and properly configured to prevent similar issues from arising in other directory service implementations.