CVE-2007-6698 in OpenLDAP
Summary
by MITRE
The BDB backend for slapd in OpenLDAP before 2.3.36 allows remote authenticated users to cause a denial of service (crash) via a potentially-successful modify operation with the NOOP control set to critical, possibly due to a double free vulnerability.
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Analysis
by VulDB Data Team • 08/05/2019
The vulnerability identified as CVE-2007-6698 affects the BDB backend implementation within OpenLDAP's slapd daemon, specifically targeting versions prior to 2.3.36. This issue represents a significant security flaw that can be exploited by remote authenticated users to disrupt service availability. The vulnerability manifests through a carefully crafted modify operation that incorporates the NOOP control with critical flag set, leading to system instability and potential service termination. The underlying technical root cause lies within the memory management handling of the BDB backend component, where improper resource deallocation occurs during the processing of such operations.
The technical exploitation of this vulnerability stems from a double free condition that occurs when slapd processes modify requests containing the NOOP control set to critical. When an authenticated user submits such a request, the BDB backend fails to properly manage memory allocation and deallocation sequences, resulting in attempts to free the same memory block twice. This classic memory corruption vulnerability typically leads to heap corruption and ultimately causes the slapd process to crash. The vulnerability is particularly concerning because it requires only authenticated access, meaning that users who have established legitimate connections to the LDAP service can potentially disrupt the entire directory service infrastructure.
From an operational impact perspective, this vulnerability creates a substantial risk for organizations relying on OpenLDAP directory services, as it can be leveraged to perform denial of service attacks against critical infrastructure. The crash resulting from this vulnerability can affect authentication services, user management systems, and any applications dependent on LDAP for directory lookups. Network administrators and security teams face the challenge of maintaining service availability while addressing this memory management flaw. The vulnerability also impacts the broader LDAP ecosystem, as it demonstrates weaknesses in the BDB backend implementation that could potentially affect other similar database backends or components within the OpenLDAP suite.
Organizations should prioritize immediate patching of affected OpenLDAP installations to address this vulnerability, as the remediation requires updating to version 2.3.36 or later where the double free issue has been resolved through improved memory management controls. Security teams should implement monitoring for unusual modify operations containing the NOOP control, as this could serve as an indicator of potential exploitation attempts. The vulnerability aligns with CWE-415, which addresses double free conditions in memory management, and can be categorized under ATT&CK technique T1499.004 for network denial of service attacks. Additionally, this issue highlights the importance of proper input validation and memory handling in enterprise directory services, emphasizing the need for regular security assessments of critical infrastructure components.