CVE-2014-3465 in GnuTLS
Summary
by MITRE
The gnutls_x509_dn_oid_name function in lib/x509/common.c in GnuTLS 3.0 before 3.1.20 and 3.2.x before 3.2.10 allows remote attackers to cause a denial of service (NULL pointer dereference) via a crafted X.509 certificate, related to a missing LDAP description for an OID when printing the DN.
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Analysis
by VulDB Data Team • 06/20/2021
The vulnerability identified as CVE-2014-3465 affects the GnuTLS library version 3.0 before 3.1.20 and 3.2.x before 3.2.10, presenting a critical denial of service condition that stems from improper handling of X.509 certificate data structures. This flaw manifests specifically within the gnutls_x509_dn_oid_name function located in lib/x509/common.c, where the library fails to adequately validate or handle certain OID (Object Identifier) values during the process of printing distinguished names from X.509 certificates. The core issue arises when processing certificates containing OIDs that lack corresponding LDAP descriptions, creating a scenario where the software attempts to dereference a NULL pointer during the certificate parsing process. This vulnerability operates under the broader category of improper input validation and memory management issues, aligning with CWE-476 which describes NULL pointer dereference conditions. The attack vector requires a remote adversary to craft a malicious X.509 certificate that contains such problematic OIDs, which when processed by vulnerable GnuTLS implementations, triggers the NULL pointer dereference and subsequently causes the application or service to crash.
The operational impact of this vulnerability extends across numerous systems and applications that rely on GnuTLS for secure communications, particularly those implementing SSL/TLS protocols for web servers, email servers, and other network services. When exploited, the denial of service condition can result in complete service unavailability, forcing system administrators to restart affected services and potentially causing significant disruption to network operations. The vulnerability's exploitation does not require authentication or specialized privileges, making it particularly dangerous as any remote user capable of submitting X.509 certificates to a vulnerable system can trigger the condition. From an attack framework perspective, this vulnerability maps to ATT&CK technique T1499.004 which covers network denial of service attacks, and more specifically to the broader category of privilege escalation and denial of service through software exploitation. The flaw essentially creates an opportunity for attackers to disrupt services by leveraging the library's insufficient error handling mechanisms when encountering unexpected certificate structures, particularly those containing OIDs without proper LDAP mappings.
Mitigation strategies for CVE-2014-3465 primarily involve immediate patching of affected GnuTLS installations to versions 3.1.20 or 3.2.10 and later, which contain the necessary fixes to properly handle missing LDAP descriptions for OIDs during certificate processing. Organizations should prioritize updating their systems, particularly those running web servers, mail servers, and any services that utilize GnuTLS for secure communications. Additional defensive measures include implementing certificate validation policies that filter out certificates with suspicious or malformed OIDs, as well as monitoring for unusual certificate processing patterns that might indicate exploitation attempts. Network administrators should also consider implementing intrusion detection systems that can identify and alert on potential exploitation attempts targeting this specific vulnerability. The fix implemented by the GnuTLS development team addresses the root cause by ensuring that the gnutls_x509_dn_oid_name function properly handles cases where LDAP descriptions are missing, preventing the NULL pointer dereference that previously occurred. This remediation aligns with industry best practices for secure coding and demonstrates the importance of robust input validation and error handling in cryptographic libraries that process untrusted data from network sources.