CVE-2003-1604 in Linux
Summary
by MITRE
The redirect_target function in net/ipv4/netfilter/ipt_REDIRECT.c in the Linux kernel before 2.6.0 allows remote attackers to cause a denial of service (NULL pointer dereference and OOPS) by sending packets to an interface that has a 0.0.0.0 IP address, a related issue to CVE-2015-8787.
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Analysis
by VulDB Data Team • 11/07/2018
The vulnerability described in CVE-2003-1604 represents a critical NULL pointer dereference flaw within the Linux kernel's netfilter subsystem, specifically affecting the redirect_target function in the ipt_REDIRECT.c file. This issue exists in kernel versions prior to 2.6.0 and demonstrates a classic buffer overflow pattern that can be exploited to trigger system instability. The vulnerability stems from inadequate input validation when processing packets destined for interfaces configured with the 0.0.0.0 IP address, which serves as a special placeholder indicating an unspecified or invalid address. The flaw operates at the network packet processing level where the kernel fails to properly validate the target address before attempting to dereference a pointer that remains uninitialized or set to NULL.
The technical exploitation of this vulnerability occurs when malicious actors send specially crafted packets to network interfaces configured with the 0.0.0.0 address, which is commonly used in routing contexts to indicate a default route or unspecified destination. When the kernel's iptables redirect mechanism processes these packets, it attempts to access a pointer that has not been properly initialized due to the invalid address configuration. This results in an immediate NULL pointer dereference that causes the kernel to crash with an OOPS message, effectively rendering the system unavailable to process legitimate network traffic. The vulnerability operates under CWE-476 which classifies NULL pointer dereference as a critical weakness in software systems, and aligns with ATT&CK technique T1499.100 which covers network denial of service attacks targeting system resources.
The operational impact of this vulnerability extends beyond simple service disruption as it can be leveraged to create persistent denial of service conditions that may require system reboot to resolve. Network administrators and system operators face significant challenges when dealing with such vulnerabilities since they can be triggered remotely without authentication, making them particularly dangerous in production environments. The vulnerability's exploitation does not require elevated privileges or specialized tools, as it can be initiated through standard network packet transmission, making it accessible to a broad range of threat actors. The affected kernel version range indicates this was a long-standing issue that persisted for several years, highlighting the importance of timely patch management and kernel security updates in enterprise environments. Organizations running older kernel versions are particularly vulnerable to this attack vector, as the flaw represents a fundamental design weakness in the packet handling mechanism that can be easily triggered through network traffic analysis and crafting.
Mitigation strategies for CVE-2003-1604 primarily focus on immediate kernel upgrades to versions 2.6.0 or later where the vulnerability has been addressed through proper input validation and pointer initialization. System administrators should implement network segmentation and access controls to limit exposure to potentially malicious traffic, while also monitoring for unusual network activity that may indicate exploitation attempts. The patch for this vulnerability involves adding proper validation checks to ensure that target addresses are properly initialized before pointer dereference operations occur, which aligns with defensive programming practices recommended in both CWE guidelines and security standards such as NIST SP 800-53. Additional defensive measures include implementing network intrusion detection systems that can identify and block packets destined for 0.0.0.0 addresses, as well as maintaining comprehensive network logging to detect potential exploitation attempts. Organizations should also conduct regular vulnerability assessments to identify other similar issues within their network infrastructure and ensure that all kernel components are kept up to date with security patches. The remediation process requires careful testing to ensure that the patch does not introduce compatibility issues with existing network configurations while maintaining the security posture against this specific denial of service vulnerability.