CVE-2011-0532 in 389 Directory Server
Summary
by MITRE
The (1) backup and restore scripts, (2) main initialization script, and (3) ldap-agent script in 389 Directory Server 1.2.x (aka Red Hat Directory Server 8.2.x) place a zero-length directory name in the LD_LIBRARY_PATH, which allows local users to gain privileges via a Trojan horse shared library in the current working directory.
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Analysis
by VulDB Data Team • 04/23/2017
The vulnerability identified as CVE-2011-0532 affects the 389 Directory Server version 1.2.x, which is also known as Red Hat Directory Server 8.2.x, presenting a critical privilege escalation risk through improper environment variable handling. This flaw manifests in three specific scripts including backup and restore operations, main initialization procedures, and ldap-agent functionality, all of which contribute to an insecure system state that can be exploited by local attackers. The core technical issue stems from the inclusion of a zero-length directory name within the LD_LIBRARY_PATH environment variable, a condition that fundamentally undermines the security model of dynamic library loading mechanisms. When a zero-length directory is present in LD_LIBRARY_PATH, the system interprets this as the current working directory, creating a dangerous precedent where any shared library placed in the current directory can be loaded with elevated privileges, effectively bypassing normal security boundaries.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential system compromise and unauthorized access to sensitive directory server data. Attackers can exploit this condition by placing a malicious shared library in the current working directory of any process that executes these vulnerable scripts, particularly during backup operations or system initialization phases when elevated privileges are active. This technique aligns with the attack pattern described in the MITRE ATT&CK framework under privilege escalation tactics, specifically leveraging the 'Dynamic Linking' technique where adversaries manipulate the dynamic linker's search path to load malicious code. The vulnerability represents a classic case of insecure library loading practices, which is formally categorized under CWE-426 as 'Untrusted Search Path', where the system's search path contains entries that can be manipulated by unprivileged users to load malicious code with elevated privileges.
The security implications of this flaw are particularly severe given that 389 Directory Server serves as a foundational component for identity and access management in enterprise environments, making it a prime target for attackers seeking persistent access to critical infrastructure. The vulnerability's persistence across multiple scripts indicates a systemic issue in the software's initialization and maintenance procedures, suggesting that proper environment variable sanitization was not implemented across the entire software ecosystem. Organizations utilizing these versions of the directory server face significant risk of unauthorized privilege escalation, potentially allowing attackers to access sensitive user information, modify directory entries, or establish persistent backdoors within their authentication systems. The exploitability of this vulnerability is enhanced by the fact that it requires minimal privileges to execute, as the zero-length directory entry is introduced during normal system operations rather than requiring special manipulation. Remediation efforts should focus on proper environment variable handling, ensuring that scripts do not include empty directory entries in LD_LIBRARY_PATH, and implementing robust privilege separation mechanisms that prevent the loading of arbitrary shared libraries during critical system operations. This vulnerability underscores the importance of proper environment sanitization and the critical need for security-conscious development practices in system-level software components that operate with elevated privileges.