CVE-2007-6742 in Tivoli Directory Server
Summary
by MITRE
The get_filter_list function in IBM Tivoli Directory Server (TDS) 5.2 before 5.2.0.5-TIV-ITDS-LA0006 does not properly perform certain sub filter parsing, which allows remote authenticated users to cause a denial of service (infinite loop) via a malformed search filter.
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Analysis
by VulDB Data Team • 01/30/2018
The vulnerability identified as CVE-2007-6742 affects IBM Tivoli Directory Server version 5.2 before 5.2.0.5-TIV-ITDS-LA0006, specifically within the get_filter_list function that handles search filter parsing operations. This issue represents a classic denial of service vulnerability that exploits improper input validation mechanisms within the directory server's filtering subsystem. The flaw manifests when the server processes malformed search filters that contain certain sub filter parsing constructs, leading to an infinite loop condition that consumes system resources and renders the service unavailable to legitimate users.
The technical implementation of this vulnerability stems from insufficient boundary checking and validation within the filter parsing logic of TDS. When an authenticated user submits a specially crafted search filter containing malformed sub filters, the get_filter_list function enters an infinite loop during the parsing process rather than properly rejecting or sanitizing the invalid input. This behavior directly violates the principle of defensive programming and demonstrates a lack of proper input sanitization measures. The vulnerability operates at the application layer and requires authentication to exploit, making it particularly dangerous in environments where privileged accounts might be compromised or where attackers can obtain legitimate credentials through social engineering or other means.
From an operational impact perspective, this vulnerability creates a significant availability risk for directory services that depend on IBM Tivoli Directory Server. The infinite loop condition consumes CPU cycles and memory resources continuously, effectively causing a denial of service that impacts all users of the directory service. Organizations relying on TDS for authentication, authorization, and directory lookups would experience complete service disruption, potentially affecting thousands of users and applications that depend on the directory infrastructure. The vulnerability's impact extends beyond simple service interruption as it can be exploited repeatedly, maintaining the denial of service condition until the server is manually restarted or the system is rebooted.
The vulnerability aligns with CWE-835, which describes the weakness of infinite loops in software implementations, and represents a specific instance of improper input validation that leads to resource exhaustion. From an attack framework perspective, this vulnerability maps to the denial of service category within the MITRE ATT&CK framework, specifically under the technique of service denial. Organizations should implement immediate mitigations including applying the vendor-provided patch, implementing network segmentation to limit access to directory services, and deploying monitoring solutions to detect anomalous search filter patterns that might indicate exploitation attempts. Additionally, implementing rate limiting and input validation controls at the network perimeter can help reduce the attack surface and provide additional defense in depth measures against similar vulnerabilities.