CVE-2007-5794 in Nss Ldap
Summary
by MITRE
Race condition in nss_ldap, when used in applications that are linked against the pthread library and fork after a call to nss_ldap, might send user data to the wrong process because of improper handling of the LDAP connection. NOTE: this issue was originally reported for Dovecot with the wrong mailboxes being returned, but other applications might also be affected.
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Analysis
by VulDB Data Team • 06/02/2025
The vulnerability described in CVE-2007-5794 represents a critical race condition within the nss_ldap library that fundamentally compromises the security of authentication and authorization processes in Unix-like systems. This flaw specifically manifests when applications utilizing nss_ldap functionality are linked against the pthread library and subsequently invoke the fork() system call after establishing LDAP connections. The underlying issue stems from improper handling of LDAP connection state management across process boundaries, creating a window where user authentication data can be inadvertently transmitted to incorrect processes. The vulnerability's impact extends beyond its initial reporting in Dovecot, where it resulted in incorrect mailboxes being returned to users, but affects any application relying on nss_ldap for name service resolution. This race condition creates a pathway for information disclosure and potential privilege escalation attacks, as the LDAP connection context becomes corrupted during the fork operation, leading to data leakage between processes that share the same connection handle. The technical nature of this vulnerability aligns with CWE-362, which specifically addresses race conditions in concurrent programming environments where improper synchronization leads to security flaws. The flaw operates at the intersection of process management and network communication, leveraging the pthread library's threading capabilities to create an exploitable condition where connection state is not properly isolated between parent and child processes. Applications that rely on nss_ldap for user lookup, group membership, and other name service functions become vulnerable to attacks where authentication credentials or sensitive user data can be exposed to unauthorized processes. The operational impact of this vulnerability is significant as it can enable attackers to gain access to user accounts, extract authentication tokens, or manipulate user permissions by exploiting the improper connection handling during process forking. This type of vulnerability falls under the ATT&CK technique T1068, which involves exploiting legitimate credentials and processes to gain system access. The flaw essentially allows for process hijacking through connection state corruption, making it particularly dangerous in multi-user environments where process isolation is critical for maintaining security boundaries. The vulnerability's exploitation requires that the target application be linked with pthread and invoke fork() after LDAP operations, which is common in server applications that need to handle multiple concurrent connections. Security professionals should recognize this as a fundamental flaw in name service resolution libraries that can undermine the entire authentication infrastructure of a system. The mitigation strategy involves ensuring proper connection handling during forking operations, typically through either disabling nss_ldap usage in multi-threaded applications, implementing proper synchronization mechanisms, or upgrading to patched versions of nss_ldap that correctly handle connection state during process forking. Additionally, system administrators should consider alternative authentication mechanisms that do not rely on this vulnerable library, particularly in high-security environments where the risk of information disclosure is unacceptable. The vulnerability demonstrates the importance of careful consideration when designing multi-threaded applications that interact with network services, as the interaction between process management and network state handling can create unexpected security implications. Organizations should conduct thorough audits of their authentication infrastructure to identify all applications that might be vulnerable to this type of race condition, as the impact extends far beyond the initial reporting context in Dovecot.