CVE-2002-0666 in NetBSD
Summary
by MITRE
IPSEC implementations including (1) FreeS/WAN and (2) KAME do not properly calculate the length of authentication data, which allows remote attackers to cause a denial of service (kernel panic) via spoofed, short Encapsulating Security Payload (ESP) packets, which result in integer signedness errors.
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Analysis
by VulDB Data Team • 06/23/2024
The vulnerability described in CVE-2002-0666 represents a critical flaw in IPsec implementations that affects both FreeS/WAN and KAME software stacks. This issue manifests in the improper calculation of authentication data length within the Encapsulating Security Payload (ESP) processing mechanisms. The flaw occurs when these implementations receive spoofed ESP packets that contain malformed length fields, leading to kernel-level system instability and potential denial of service conditions.
The technical root cause of this vulnerability stems from integer signedness errors during the processing of ESP packet headers. When the IPsec implementation encounters a spoofed packet with a shortened ESP payload, the system fails to properly validate the length parameters before performing arithmetic operations on them. This results in signed integer overflow conditions that cause the kernel to crash with a panic state. The vulnerability specifically affects the authentication data calculation routines where unsigned and signed integer types are improperly handled, creating a scenario where maliciously crafted packets can trigger system-level failures.
From an operational perspective, this vulnerability presents a significant threat to network security infrastructure that relies on IPsec for secure communications. Attackers can exploit this weakness by crafting spoofed ESP packets with manipulated length fields, causing legitimate IPsec implementations to crash and restart their kernel processes. The impact extends beyond simple service disruption as kernel panics can lead to complete system outages, particularly in environments where IPsec is critical for network security. The vulnerability affects systems running FreeS/WAN and KAME implementations, which were widely deployed in enterprise and government networks during the early 2000s, making this a historically significant security flaw with widespread potential impact.
The vulnerability aligns with CWE-191, which addresses integer underflow and overflow conditions, and demonstrates characteristics consistent with ATT&CK technique T1499.1, specifically focusing on network denial of service attacks. Organizations implementing IPsec solutions should consider immediate patching of affected FreeS/WAN and KAME installations, along with network monitoring to detect potential exploitation attempts. Implementing proper packet validation and length checking mechanisms within IPsec implementations can prevent this class of integer signedness errors from causing system crashes. Additionally, network segmentation and intrusion detection systems should be configured to monitor for unusual ESP packet patterns that might indicate exploitation attempts. The fix typically involves correcting the integer handling logic to properly validate packet lengths before processing and ensuring that signedness mismatches do not occur during authentication data calculations, thereby preventing the kernel panic conditions that enable the denial of service attack.