CVE-2009-1574 in ipsec-tools
Summary
by MITRE
racoon/isakmp_frag.c in ipsec-tools before 0.7.2 allows remote attackers to cause a denial of service (crash) via crafted fragmented packets without a payload, which triggers a NULL pointer dereference.
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Analysis
by VulDB Data Team • 12/28/2024
The vulnerability identified as CVE-2009-1574 resides within the racoon implementation of the ipsec-tools package, specifically in the isakmp_frag.c file. This flaw affects versions prior to 0.7.2 and represents a critical denial of service vulnerability that can be exploited by remote attackers to crash the affected system. The vulnerability manifests when the system receives crafted fragmented Internet Protocol Security (IPsec) packets that lack a payload component, creating a scenario where the software fails to properly handle the absence of expected data structures.
The technical root cause of this vulnerability stems from a NULL pointer dereference condition that occurs during the processing of fragmented ISAKMP (Internet Security Association and Key Management Protocol) packets. When racoon encounters fragmented packets without payloads, the code fails to properly validate the presence of necessary data structures before attempting to access them. This fundamental flaw in input validation and memory management creates a path where the program attempts to dereference a null pointer, leading to an immediate crash of the racoon daemon. The vulnerability specifically impacts the fragmentation handling mechanism within the ISAKMP protocol implementation, where the software assumes the presence of certain packet components that may not exist in maliciously crafted packets.
From an operational perspective, this vulnerability presents a significant risk to network security infrastructure that relies on IPsec for secure communications. The remote exploitation capability means that attackers can potentially disrupt security services without requiring local access or authentication credentials, making it particularly dangerous in environments where IPsec gateways or VPN concentrators are deployed. The denial of service impact extends beyond simple service disruption, as the crash of the racoon daemon can lead to complete loss of IPsec connectivity for affected systems, potentially exposing networks to further attacks or compromising the integrity of security policies. The vulnerability can be exploited by sending specially crafted fragmented packets that bypass normal protocol validation, making detection and prevention challenging.
The vulnerability aligns with CWE-476 which describes NULL pointer dereference conditions, and represents a classic example of improper input validation in security-critical network software. From an attack framework perspective, this vulnerability maps to the denial of service category within the MITRE ATT&CK framework, specifically targeting network infrastructure components that provide security services. Organizations using affected versions of ipsec-tools should immediately implement mitigation strategies including updating to version 0.7.2 or later, implementing network segmentation to limit exposure, and deploying intrusion detection systems that can identify and block malicious fragmented packet patterns. The fix implemented in version 0.7.2 addresses the core issue by adding proper NULL pointer checks and robust validation of packet structures before attempting to process fragmented ISAKMP messages, ensuring that the software gracefully handles malformed input rather than crashing.