CVE-2009-5072 in Tivoli Directory Server
Summary
by MITRE
Memory leak in the ldap_explode_dn function in IBM Tivoli Directory Server (TDS) 6.0 before 6.0.0.61 (aka 6.0.0.8-TIV-ITDS-IF0003) allows remote authenticated users to cause a denial of service (memory consumption) via an empty string argument.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 01/26/2018
The vulnerability identified as CVE-2009-5072 represents a critical memory management flaw within IBM Tivoli Directory Server version 6.0 prior to 6.0.0.61. This issue specifically affects the ldap_explode_dn function which is responsible for parsing distinguished names in LDAP (Lightweight Directory Access Protocol) operations. The flaw manifests when the function receives an empty string argument as input, causing the server to allocate memory resources without proper cleanup mechanisms. This memory leak occurs in the context of authenticated remote access, meaning that an attacker must first establish valid credentials to exploit the vulnerability, though the impact remains severe as it can lead to complete service unavailability.
The technical implementation of this vulnerability stems from improper memory handling within the ldap_explode_dn function where the server fails to release allocated memory blocks when processing empty string inputs. This type of memory leak falls under the category of CWE-401, which specifically addresses improper release of memory resources. The vulnerability operates by consuming system memory resources incrementally with each affected LDAP operation, eventually leading to memory exhaustion. The attack vector requires remote access with valid authentication credentials, making it a privilege-escalation related issue that can be exploited by authenticated users who may not have administrative privileges but can still cause significant operational disruption.
From an operational impact perspective, this vulnerability directly translates to a denial of service condition where the targeted IBM Tivoli Directory Server becomes unresponsive due to excessive memory consumption. The memory leak progressively consumes available system resources, potentially causing the server to crash or become unresponsive to legitimate LDAP queries. This affects directory services that rely on TDS for user authentication, authorization, and directory lookups, which can cascade into broader system failures within organizations that depend on centralized directory services for their IT infrastructure. The vulnerability is particularly concerning because it can be exploited continuously over time without requiring special privileges beyond authentication, making it a persistent threat to service availability.
Organizations should implement immediate mitigations including applying the vendor-provided patch version 6.0.0.61 or higher which addresses the memory leak in the ldap_explode_dn function. Network segmentation and access controls should be enhanced to limit the number of authenticated users who can access LDAP services, reducing the attack surface. Monitoring systems should be configured to detect unusual memory consumption patterns in directory server processes, enabling early detection of potential exploitation attempts. The vulnerability also aligns with ATT&CK technique T1499.004 which covers network denial of service attacks, and represents a specific implementation of the broader category of resource exhaustion attacks that can compromise system availability. Security teams should conduct regular vulnerability assessments to ensure all instances of IBM Tivoli Directory Server are updated and monitored for similar memory management issues that could lead to similar denial of service conditions.