CVE-2007-5031 in Dibbler
Summary
by MITRE
The TSrvOptIA_NA::rebind method in SrvOptions/SrvOptIA_NA.cpp in Dibbler 0.6.0 allows remote attackers to cause a denial of service (NULL dereference and daemon crash) via an invalid IA_NA option in a REBIND message.
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Analysis
by VulDB Data Team • 07/29/2021
The vulnerability identified as CVE-2007-5031 affects the Dibbler DHCPv6 server implementation version 0.6.0, specifically within the TSrvOptIA_NA::rebind method located in the SrvOptions/SrvOptIA_NA.cpp source file. This flaw represents a classic null pointer dereference issue that occurs when processing invalid IA_NA (Identity Association for Non-temporary Addresses) options within REBIND messages. The vulnerability arises from insufficient input validation and error handling mechanisms within the DHCPv6 server's option processing logic, creating a condition where malformed network traffic can trigger unexpected program termination.
The technical exploitation of this vulnerability occurs when a remote attacker crafts a malicious REBIND message containing an invalid IA_NA option structure. When the Dibbler server receives such a message and attempts to process it through the rebind method, the code fails to properly validate the IA_NA option's integrity before attempting to dereference pointers associated with the option's data structures. This results in a NULL pointer dereference exception that causes the daemon process to crash and terminate unexpectedly. The vulnerability demonstrates characteristics consistent with CWE-476, which describes NULL pointer dereference conditions that can lead to denial of service scenarios.
The operational impact of this vulnerability extends beyond simple service disruption, as it provides attackers with a reliable method for causing persistent denial of service against DHCPv6 services. Network administrators relying on Dibbler for IPv6 address management face significant operational risks when this vulnerability exists in their infrastructure, as the daemon crash can occur at any time when processing legitimate or malicious REBIND messages. The vulnerability affects the availability aspect of the CIA triad, potentially disrupting network connectivity for devices dependent on the affected DHCPv6 server. This type of vulnerability aligns with ATT&CK technique T1499.004, which covers network denial of service attacks targeting infrastructure services.
Mitigation strategies for this vulnerability should focus on immediate patching of the Dibbler software to version 0.6.1 or later, which contains the necessary fixes for proper input validation and error handling. Organizations should also implement network monitoring to detect unusual REBIND message patterns and consider implementing rate limiting or filtering rules to prevent malformed DHCPv6 traffic from reaching the server. Additionally, system administrators should ensure that the DHCPv6 server operates with appropriate process monitoring and automatic restart capabilities to minimize service disruption. The fix typically involves adding proper validation checks before pointer dereference operations and implementing graceful error handling that prevents the daemon from crashing when encountering malformed options, thereby maintaining service availability and system stability.