CVE-2012-3429 in bind-dyndb-ldap
Summary
by MITRE
The dns_to_ldap_dn_escape function in src/ldap_convert.c in bind-dyndb-ldap 1.1.0rc1 and earlier does not properly escape distinguished names (DN) for LDAP queries, which allows remote DNS servers to cause a denial of service (named service hang) via a "$" character in a DN in a DNS query.
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Analysis
by VulDB Data Team • 12/31/2024
The vulnerability identified as CVE-2012-3429 resides within the bind-dyndb-ldap plugin version 1.1.0rc1 and earlier, specifically in the dns_to_ldap_dn_escape function located in src/ldap_convert.c. This flaw represents a critical security issue that affects DNS resolution services when integrated with LDAP backends, creating a potential denial of service condition that can severely impact network infrastructure availability. The vulnerability stems from inadequate handling of special characters during the conversion process between DNS names and LDAP distinguished names, which are fundamental components in directory service integration for dynamic DNS updates.
The technical implementation flaw occurs when the dns_to_ldap_dn_escape function fails to properly escape the "$" character in distinguished names during LDAP query construction. This character escaping deficiency allows malicious DNS servers to inject malformed distinguished names that contain unescaped special characters, particularly the dollar sign which has special meaning in LDAP query syntax. When the named service processes these malformed queries, it attempts to convert the DNS names to LDAP distinguished names without proper sanitization, leading to malformed LDAP queries that can cause the named service to hang or become unresponsive. The vulnerability specifically targets the LDAP conversion logic where DNS names are transformed into directory service identifiers, creating a path for arbitrary input to disrupt service operations.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise entire network infrastructure availability. When exploited, the vulnerability can cause the named service to enter an indefinite hang state, effectively rendering DNS resolution services unavailable to clients. This denial of service condition can cascade through network systems that depend on proper DNS resolution, affecting email services, web applications, and other network-dependent operations. The attack vector requires only that a remote DNS server submit a query containing a "$" character in a DNS name, making the exploit relatively simple to execute against vulnerable systems. Organizations using bind-dyndb-ldap integration are particularly at risk since the vulnerability affects the core functionality of dynamic DNS updates through LDAP backends, potentially allowing attackers to maintain persistent service disruption.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term architectural improvements to prevent similar issues. The primary solution involves upgrading to bind-dyndb-ldap version 1.1.0rc2 or later, where the dns_to_ldap_dn_escape function has been properly implemented with comprehensive character escaping mechanisms. Additionally, system administrators should implement network-level filtering to restrict DNS query traffic from untrusted sources and consider implementing monitoring solutions that can detect unusual patterns in DNS resolution requests that may indicate exploitation attempts. From a security architecture perspective, this vulnerability aligns with CWE-174, which addresses the weakness of insufficient escaping of special characters, and represents a specific implementation of the broader category of injection flaws that can lead to service disruption. The ATT&CK framework categorizes this as a denial of service attack vector through service manipulation, where adversaries exploit implementation flaws to compromise system availability and can be mitigated through proper input validation and character escaping controls as recommended in the CWE guidelines.