CVE-2005-0067 in TCP
Summary
by MITRE
The original design of TCP does not require that port numbers be assigned randomly (aka "Port randomization"), which makes it easier for attackers to forge ICMP error messages for specific TCP connections and cause a denial of service, as demonstrated using (1) blind connection-reset attacks with forged "Destination Unreachable" messages, (2) blind throughput-reduction attacks with forged "Source Quench" messages, or (3) blind throughput-reduction attacks with forged ICMP messages that cause the Path MTU to be reduced. 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 • 06/30/2021
The vulnerability described in CVE-2005-0067 stems from a fundamental design flaw in the Transmission Control Protocol that lacks mandatory port number randomization mechanisms. This weakness in the original TCP specification creates exploitable conditions that allow malicious actors to manipulate network communications through forged ICMP error messages. The absence of random port assignment means that attackers can predict or guess port numbers associated with specific TCP connections, fundamentally undermining the security assumptions that govern connection integrity and network reliability. This vulnerability specifically affects the TCP implementation's handling of port numbers during connection establishment and maintenance phases, creating persistent attack vectors that remain relevant in modern network security contexts.
The technical exploitation of this vulnerability occurs through three primary attack vectors that leverage the predictable nature of port assignments in TCP connections. The first vector involves blind connection-reset attacks where attackers forge "Destination Unreachable" ICMP messages to disrupt active TCP sessions without direct access to the target network. The second vector utilizes "Source Quench" messages to perform blind throughput-reduction attacks that significantly impact network performance and application availability. The third vector exploits ICMP messages that manipulate Path MTU (Maximum Transmission Unit) values to reduce network throughput and create denial of service conditions. These attacks demonstrate how the lack of port randomization creates predictable patterns that adversaries can exploit to compromise network services and establish persistent disruption capabilities.
The operational impact of CVE-2005-0067 extends beyond simple service disruption to encompass broader network reliability and security concerns. Organizations implementing TCP-based services face significant risks including complete service outages, performance degradation, and potential data loss during attack execution. The vulnerability affects all systems that rely on TCP for network communication, making it particularly dangerous in enterprise environments where network stability is critical for business operations. Network administrators must contend with the fact that these attacks can be executed without requiring deep network knowledge or privileged access, making them particularly effective against poorly configured systems. The vulnerability's persistence across multiple implementations means that organizations cannot simply patch individual applications but must address the underlying TCP stack behaviors that enable these attacks.
This vulnerability aligns with CWE-1009, which describes weaknesses in the design of network protocols that fail to implement proper randomization mechanisms. The attack patterns described in CVE-2005-0067 correspond to techniques found in the ATT&CK framework under the T1498 category, specifically targeting network denial of service through manipulation of network protocols. The vulnerability demonstrates how protocol-level design flaws can create systemic security issues that affect entire network infrastructures rather than individual applications. Security professionals should recognize that this vulnerability represents a classic example of how insufficient randomness in network protocol implementations can lead to widespread exploitation opportunities. The relationship between CVE-2005-0067 and related identifiers such as CVE-2005-0065, CVE-2005-0066, and CVE-2005-0068 illustrates how different attack vectors can exploit the same underlying protocol weakness, emphasizing the need for comprehensive protocol-level solutions rather than individual attack-specific patches.
Mitigation strategies for CVE-2005-0067 require implementation of proper port randomization mechanisms at the operating system level and network stack configuration. Organizations should deploy systems that implement randomized port assignment for outbound connections, ensuring that ephemeral port selection follows cryptographic randomness principles rather than predictable sequences. Network administrators should configure firewalls and intrusion detection systems to monitor for suspicious ICMP message patterns that could indicate exploitation attempts. The implementation of TCP stack hardening measures including proper sequence number randomization and connection tracking mechanisms provides defense-in-depth against these attacks. System administrators must also consider network segmentation and access control measures to limit the potential impact of successful exploitation attempts. Regular security assessments and network monitoring should focus on identifying systems that may still be vulnerable to these legacy protocol-based attacks, particularly in environments with older network infrastructure that may not have received appropriate security updates.