CVE-2005-3810 in Linux
Summary
by MITRE
ip_conntrack_proto_icmp.c in ctnetlink in Linux kernel 2.6.14 up to 2.6.14.3 allows attackers to cause a denial of service (kernel oops) via a message without ICMP ID (ICMP_ID) information, which leads to a null dereference.
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Analysis
by VulDB Data Team • 04/13/2019
The vulnerability identified as CVE-2005-3810 represents a critical kernel-level flaw in the Linux networking subsystem that specifically affects the connection tracking module for ICMP protocol handling. This issue resides within the ip_conntrack_proto_icmp.c file, which is part of the ctnetlink framework responsible for managing network connection tracking in kernel versions 2.6.14 through 2.6.14.3. The vulnerability stems from inadequate input validation and error handling when processing ICMP packets that lack the required ICMP ID field information, creating a condition where the kernel fails to properly validate packet structure before attempting to access memory locations.
The technical exploitation of this vulnerability occurs when an attacker crafts an ICMP packet that omits the standard ICMP ID field, which is typically present in ICMP echo requests and replies. When the kernel's connection tracking module processes such malformed packets, it attempts to dereference a null pointer in the absence of proper validation checks. This null pointer dereference results in an immediate kernel oops condition, which is a kernel-level error that causes the system to crash or become unresponsive. The flaw specifically manifests in the protocol handling logic where the kernel assumes the presence of ICMP ID information without verifying its existence, leading to a direct memory access violation that terminates kernel execution.
The operational impact of this vulnerability extends beyond simple denial of service, as it can be exploited by remote attackers to systematically disrupt network services on affected systems. The kernel oops condition typically results in immediate system instability, requiring manual intervention to restore normal operation through system reboot. This makes the vulnerability particularly dangerous in network infrastructure devices, servers, or any system where continuous availability is critical. The vulnerability affects systems running kernel versions that are part of the 2.6.14.x release series, which were widely deployed in enterprise and network environments during that time period, making the potential attack surface substantial.
Mitigation strategies for CVE-2005-3810 primarily involve applying the official kernel patches released by the Linux kernel development team, which include enhanced input validation and proper null pointer checks in the ICMP handling code. System administrators should prioritize updating their kernel versions to 2.6.14.4 or later, where the vulnerability has been addressed through code modifications that validate ICMP packet structures before processing. Network administrators can also implement additional defensive measures such as ICMP filtering rules in firewalls to drop malformed ICMP packets at the network boundary, though this approach provides only partial protection as the vulnerability exists within the kernel itself. This vulnerability aligns with CWE-476, which describes null pointer dereference issues, and represents a classic example of insufficient input validation that can be leveraged for privilege escalation or persistent denial of service attacks according to ATT&CK technique T1499.004 for network denial of service.
The broader implications of this vulnerability highlight the critical importance of kernel security validation and proper error handling in operating system components. The flaw demonstrates how seemingly minor protocol handling inconsistencies can lead to complete system compromise, emphasizing the need for comprehensive security testing of kernel modules and connection tracking systems. Organizations should implement regular kernel update policies and maintain awareness of security advisories from kernel development teams to prevent exploitation of similar vulnerabilities that may exist in their systems. The vulnerability also underscores the importance of defensive programming practices in kernel space where memory safety is paramount and error conditions must be properly handled to prevent system crashes and potential exploitation by malicious actors.