CVE-2011-0413 in DHCP
Summary
by MITRE
The DHCPv6 server in ISC DHCP 4.0.x and 4.1.x before 4.1.2-P1, 4.0-ESV and 4.1-ESV before 4.1-ESV-R1, and 4.2.x before 4.2.1b1 allows remote attackers to cause a denial of service (assertion failure and daemon crash) by sending a message over IPv6 for a declined and abandoned address.
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Analysis
by VulDB Data Team • 12/01/2024
The vulnerability described in CVE-2011-0413 represents a critical denial of service weakness in the DHCPv6 server implementation within ISC DHCP versions 4.0.x and 4.1.x prior to specific patch releases, as well as in the 4.0-ESV and 4.1-ESV branches before their respective updates, and 4.2.x before 4.2.1b1. This flaw specifically targets the handling of IPv6 messages related to addresses that have been marked as declined and abandoned within the DHCPv6 protocol framework. The vulnerability operates through a well-defined attack vector where remote adversaries can exploit the server's insufficient input validation and state management mechanisms to trigger an assertion failure that ultimately results in daemon crash and complete service disruption.
The technical root cause of this vulnerability lies in the insufficient validation of DHCPv6 messages received for addresses that have already been marked as declined or abandoned in the server's address management system. When a DHCPv6 server processes a message for such a state, the implementation fails to properly handle the edge case where a client might attempt to renew or request a lease for an address that has been previously rejected and removed from the active allocation pool. This specific scenario triggers an assertion failure within the server's internal state management logic, causing the daemon process to terminate abruptly. The flaw manifests as a classic assertion failure pattern that violates the expected state transitions in the DHCPv6 server implementation, resulting in an immediate crash of the service.
From an operational impact perspective, this vulnerability creates a severe availability risk for networks relying on ISC DHCPv6 servers for IPv6 address allocation. The attack requires minimal resources from the attacker, who only needs to send a single malicious DHCPv6 message over IPv6 to trigger the service disruption. Network administrators face the challenge of maintaining continuous IPv6 service availability, as the crash affects the entire DHCPv6 daemon process rather than individual connections or clients. The vulnerability directly maps to CWE-248, an unspecified flaw in the software that allows for an assertion failure, and aligns with ATT&CK technique T1499.002 for network denial of service attacks. Organizations experiencing this vulnerability may face extended network outages, particularly in environments where IPv6 services are critical for device connectivity and network operations.
The mitigation strategy for CVE-2011-0413 involves immediate deployment of patched versions of ISC DHCP software, specifically upgrading to versions 4.1.2-P1, 4.1-ESV-R1, or 4.2.1b1 respectively, depending on the affected branch. System administrators should implement comprehensive patch management procedures to ensure all DHCPv6 servers within their infrastructure receive the necessary updates. Additional defensive measures include implementing network segmentation to limit exposure of vulnerable DHCPv6 servers, deploying intrusion detection systems to monitor for suspicious DHCPv6 message patterns, and establishing robust monitoring protocols to detect service disruption events. The vulnerability also highlights the importance of proper state management and input validation in network services, particularly those handling dynamic address allocation protocols. Organizations should conduct regular security assessments of their DHCP implementations and ensure that all network infrastructure components are maintained with current security patches to prevent exploitation of similar assertion failure vulnerabilities in the future.