CVE-2004-0461 in DHCP
Summary
by MITRE
The DHCP daemon (DHCPD) for ISC DHCP 3.0.1rc12 and 3.0.1rc13, when compiled in environments that do not provide the vsnprintf function, uses C include files that define vsnprintf to use the less safe vsprintf function, which can lead to buffer overflow vulnerabilities that enable a denial of service (server crash) and possibly execute arbitrary code.
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Analysis
by VulDB Data Team • 11/19/2024
The vulnerability described in CVE-2004-0461 affects the Internet Systems Consortium DHCP daemon version 3.0.1rc12 and 3.0.1rc13, representing a critical security flaw in network infrastructure software that serves as a foundational component for dynamic IP address allocation in TCP/IP networks. This issue arises from a subtle but dangerous implementation choice in the software's string handling mechanisms, where the DHCP daemon fails to properly manage buffer boundaries during string formatting operations, creating exploitable conditions that can compromise system integrity and availability.
The technical flaw stems from the absence of the vsnprintf function in certain compilation environments, which forces the DHCP daemon to rely on alternative implementations that substitute this function with the less secure vsprintf function. This substitution creates a buffer overflow condition because vsprintf does not perform bounds checking on the destination buffer, unlike its safer counterpart vsnprintf which properly validates input lengths. The vulnerability manifests when the DHCP daemon processes malformed or specially crafted DHCP requests that trigger the problematic string formatting code path, allowing an attacker to overflow buffers and potentially overwrite adjacent memory locations.
This vulnerability presents significant operational risks to network infrastructure, as it can enable both denial of service attacks that crash the DHCP server and potentially arbitrary code execution on the affected system. The denial of service aspect can disrupt network operations by causing the DHCP daemon to crash, leaving network devices unable to obtain IP addresses and effectively breaking network connectivity for affected clients. The arbitrary code execution potential, while requiring specific conditions, represents a severe threat to system integrity as it could allow attackers to gain unauthorized control over the DHCP server, potentially enabling them to manipulate network traffic, redirect clients to malicious servers, or establish persistent backdoors within the network infrastructure.
The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and CWE-122, which addresses heap-based buffer overflow scenarios, both of which are directly applicable to the unsafe string handling practices in the affected DHCP daemon versions. From an attack framework perspective, this vulnerability maps to ATT&CK technique T1059.007 for command and script injection, and T1499.004 for network denial of service, demonstrating how the flaw can be leveraged to achieve both service disruption and system compromise. The attack surface is particularly concerning given that DHCP servers typically operate with elevated privileges and are essential network services that cannot easily be replaced or isolated from normal network operations.
Mitigation strategies for this vulnerability involve immediate patching of affected systems with updated versions of ISC DHCP that properly implement the vsnprintf function or provide alternative safe string handling mechanisms. Organizations should also implement network segmentation and monitoring to detect anomalous DHCP traffic patterns that might indicate exploitation attempts, while ensuring that DHCP servers operate in secure environments with appropriate access controls and privilege separation. Additionally, network administrators should consider implementing DHCP snooping and other network security measures to limit the potential impact of successful exploitation attempts. The vulnerability underscores the importance of proper input validation and secure coding practices, particularly in network infrastructure software where buffer overflows can have cascading effects on overall network security and availability.