CVE-2015-0971 in Suricata
Summary
by MITRE
The DER parser in Suricata before 2.0.8 allows remote attackers to cause a denial of service (crash) via vectors related to SSL/TLS certificates.
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Analysis
by VulDB Data Team • 12/01/2024
The vulnerability identified as CVE-2015-0971 represents a critical denial of service weakness within the Suricata network intrusion detection system. This flaw specifically targets the Data Encapsulation Representation (DER) parser component that processes SSL/TLS certificates during network traffic analysis. The vulnerability exists in Suricata versions prior to 2.0.8, making a significant portion of deployments susceptible to exploitation. The issue stems from inadequate input validation and error handling within the certificate parsing logic, which fails to properly process malformed or specially crafted DER encoded certificates. This weakness enables remote attackers to craft malicious certificate data that triggers unexpected behavior in the parsing routine, ultimately leading to system instability and complete service disruption.
The technical implementation of this vulnerability involves the manipulation of certificate data structures during the SSL/TLS handshake process that Suricata monitors. When the system encounters malformed DER encoded certificate data, the parser fails to gracefully handle the unexpected input, resulting in memory corruption or stack overflow conditions. The vulnerability falls under CWE-129, which describes improper validation of array indices, and CWE-248, which covers exposure of exception information. The attack vector is particularly dangerous because it can be executed remotely without requiring authentication, making it an attractive target for automated exploitation. The parsing logic does not adequately implement bounds checking or input sanitization, allowing malicious certificate structures to bypass normal validation procedures and directly impact the application's memory management systems.
From an operational perspective, this vulnerability presents a severe risk to network security infrastructure that relies on Suricata for intrusion detection and monitoring. The remote code execution capability, while not directly enabling privilege escalation, creates a persistent threat that can be exploited to disrupt critical network services. Organizations utilizing Suricata for network traffic analysis face potential downtime that could compromise their overall security posture and incident response capabilities. The impact extends beyond simple service disruption, as the system crash can result in loss of network visibility during the recovery period, leaving networks vulnerable to other threats. This vulnerability aligns with ATT&CK technique T1499.004, which involves network denial of service attacks, and represents a significant concern for organizations that depend on continuous network monitoring for threat detection.
Mitigation strategies for CVE-2015-0971 primarily focus on immediate version updates to Suricata 2.0.8 or later, which contain patched implementations of the DER parser with proper input validation. Network administrators should implement comprehensive patch management protocols to ensure all instances of Suricata are updated promptly. Additional protective measures include implementing network segmentation to limit exposure, deploying intrusion prevention systems with signature updates, and establishing monitoring protocols to detect unusual traffic patterns that might indicate exploitation attempts. Organizations should also consider implementing certificate validation policies that limit the types of certificates processed by the system and establish automated alerting mechanisms for system crashes or unexpected behavior. The vulnerability highlights the importance of maintaining up-to-date security software and implementing robust input validation practices as fundamental defensive measures against similar classes of attacks.