CVE-2004-1060 in Host
Summary
by MITRE
Multiple TCP/IP and ICMP implementations, when using Path MTU (PMTU) discovery (PMTUD), allow remote attackers to cause a denial of service (network throughput reduction for TCP connections) via forged ICMP ("Fragmentation Needed and Don t Fragment was Set") packets with a low next-hop MTU value, aka the "Path MTU discovery attack." NOTE: CVE-2004-0790, CVE-2004-0791, and CVE-2004-1060 have been SPLIT based on different attacks; CVE-2005-0065, CVE-2005-0066, CVE-2005-0067, and CVE-2005-0068 are related identifiers that are SPLIT based on the underlying vulnerability. While CVE normally SPLITs based on vulnerability, the attack-based identifiers exist due to the variety and number of affected implementations and solutions that address the attacks instead of the underlying vulnerabilities.
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Analysis
by VulDB Data Team • 01/12/2025
The vulnerability described in CVE-2004-1060 represents a critical weakness in network protocol implementations that affects TCP/IP and ICMP protocols when utilizing Path MTU discovery mechanisms. This flaw enables remote attackers to manipulate network throughput by exploiting the way systems handle ICMP fragmentation notifications, specifically targeting the "Fragmentation Needed and Don't Fragment was Set" message type. The vulnerability stems from the fundamental assumption that ICMP packets are legitimate and properly formatted, creating an attack surface where malicious actors can manipulate network path characteristics to degrade service quality.
The technical exploitation of this vulnerability occurs through the manipulation of PMTUD processes that are designed to optimize network performance by discovering the maximum transmission unit size along a network path. When systems receive forged ICMP packets reporting a lower MTU value than actually exists, they update their path MTU cache and subsequently fragment outgoing packets at smaller sizes, causing significant network throughput degradation for TCP connections. This attack specifically targets the trust model inherent in network protocol implementations where ICMP responses are accepted without proper validation of their authenticity or legitimacy.
Network throughput reduction manifests as decreased performance for TCP connections as the system begins fragmenting packets at increasingly smaller sizes based on the forged ICMP information. The attack can be particularly devastating in high-bandwidth environments where TCP connections are established and maintained over long periods. This vulnerability affects numerous implementations across different operating systems and network equipment, making it a widespread concern that requires coordinated mitigation strategies. The impact extends beyond simple denial of service to include performance degradation that can affect business-critical applications and services.
The attack mechanism aligns with several ATT&CK framework techniques including T1498 (Network Denial of Service) and T1071.004 (Application Layer Protocol: DNS) where the manipulation of network path characteristics affects service availability. From a CWE perspective, this vulnerability corresponds to CWE-20 (Improper Input Validation) and CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) as it involves improper validation of ICMP packet contents and potential buffer manipulation. The vulnerability demonstrates how protocol-level trust assumptions can be exploited to cause significant operational impact, highlighting the importance of input validation and authentication mechanisms in network protocols.
Mitigation strategies include implementing proper ICMP packet validation mechanisms that verify the authenticity of fragmentation notifications, configuring systems to ignore ICMP messages that appear to be generated from unexpected sources, and implementing rate limiting for ICMP responses. Network administrators should also consider implementing source address validation and monitoring for anomalous ICMP traffic patterns that could indicate exploitation attempts. The solution approach should focus on strengthening the trust model for ICMP responses while maintaining network functionality, as complete removal of PMTUD functionality would impact network performance for legitimate users. Organizations should also implement network segmentation and access control measures to limit the impact of successful attacks on critical network infrastructure.