CVE-2014-3571 in Enterprise Session Border Controller
Summary
by MITRE
OpenSSL before 0.9.8zd, 1.0.0 before 1.0.0p, and 1.0.1 before 1.0.1k allows remote attackers to cause a denial of service (NULL pointer dereference and application crash) via a crafted DTLS message that is processed with a different read operation for the handshake header than for the handshake body, related to the dtls1_get_record function in d1_pkt.c and the ssl3_read_n function in s3_pkt.c.
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Analysis
by VulDB Data Team • 09/27/2022
This vulnerability resides in the OpenSSL cryptographic library, specifically affecting versions prior to 0.9.8zd, 1.0.0p, and 1.0.1k, presenting a critical denial of service risk through NULL pointer dereference. The flaw manifests when processing crafted DTLS messages that exploit an inconsistent read operation between handshake headers and body data, creating a scenario where the application crashes due to improper memory handling. The vulnerability is rooted in the dtls1_get_record function within d1_pkt.c and the ssl3_read_n function in s3_pkt.c, which handle different aspects of DTLS packet processing with mismatched data interpretation approaches. This inconsistency allows attackers to construct malicious DTLS packets that trigger a NULL pointer dereference when the application attempts to process the handshake data.
The technical execution of this vulnerability involves manipulating the DTLS protocol's message parsing logic where the header and body of handshake messages are processed using different read mechanisms. When an attacker sends a specially crafted DTLS packet, the system's handling of the handshake header and body becomes misaligned, leading to a scenario where a NULL pointer is dereferenced during the packet processing. This occurs because the dtls1_get_record function does not properly validate the relationship between header and body data, while ssl3_read_n function fails to account for the inconsistent processing flow. The vulnerability essentially creates a condition where the application attempts to access memory at a NULL address, causing an immediate crash and termination of the service.
From an operational impact perspective, this vulnerability presents a significant risk to any system relying on OpenSSL for DTLS communication, particularly in environments where services must remain available such as VoIP systems, IoT devices, or any network infrastructure utilizing DTLS protocols. The denial of service can be achieved remotely without authentication, making it particularly dangerous as attackers can disrupt services simply by sending malicious packets to target systems. The crash affects the entire application rather than just specific connections, potentially leading to complete service unavailability and requiring system restarts to restore normal operations. This vulnerability falls under CWE-476 which describes NULL pointer dereference, and aligns with ATT&CK technique T1499.1 for network denial of service attacks.
Mitigation strategies for this vulnerability require immediate patching of OpenSSL installations to versions 0.9.8zd, 1.0.0p, or 1.0.1k, depending on the affected version in use. System administrators should conduct comprehensive vulnerability assessments to identify all systems utilizing vulnerable OpenSSL versions and prioritize patch deployment across all network infrastructure. Network-level mitigations can include implementing firewall rules to restrict DTLS traffic or deploying intrusion detection systems that monitor for malformed DTLS packets. Additionally, organizations should consider implementing application-level monitoring to detect service disruptions and automatic restart mechanisms to minimize downtime. The patch addresses the core issue by ensuring consistent read operations between handshake header and body processing, eliminating the NULL pointer dereference condition through proper validation and memory handling procedures in both the dtls1_get_record and ssl3_read_n functions.