CVE-2007-5030 in Dibbler
Summary
by MITRE
Multiple integer overflows in Dibbler 0.6.0 allow remote attackers to cause a denial of service (daemon crash) via packets containing options with large lengths, which trigger attempts at excessive memory allocation, as demonstrated by (1) the TSrvMsg constructor in SrvMessages/SrvMsg.cpp; the (2) TClntMsg, (3) TClntOptIAAddress, (4) TClntOptIAPrefix, (5) TOptVendorSpecInfo, and (6) TOptOptionRequest constructors; and the (7) TRelIfaceMgr::decodeRelayRepl, (8) TRelMsg::decodeOpts, and (9) TSrvIfaceMgr::decodeRelayForw methods.
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Analysis
by VulDB Data Team • 09/08/2018
The vulnerability identified as CVE-2007-5030 represents a critical integer overflow issue affecting the Dibbler DHCPv6 implementation version 0.6.0. This flaw resides within the core packet processing mechanisms of the DHCPv6 server and client components, specifically targeting the handling of option lengths in network packets. The vulnerability stems from inadequate input validation and arithmetic overflow conditions that occur when processing DHCPv6 options with artificially large length fields, creating a scenario where the software attempts to allocate excessive memory resources beyond normal operational bounds.
The technical implementation of this vulnerability manifests across multiple constructors and parsing methods within the Dibbler codebase, with the primary affected components including the TSrvMsg constructor in SrvMessages/SrvMsg.cpp, along with several client-side constructors such as TClntMsg, TClntOptIAAddress, TClntOptIAPrefix, TOptVendorSpecInfo, and various relay processing methods like TRelIfaceMgr::decodeRelayRepl, TRelMsg::decodeOpts, and TSrvIfaceMgr::decodeRelayForw. These locations demonstrate a systematic flaw where option length fields are directly used in memory allocation calculations without proper bounds checking or overflow detection mechanisms. The vulnerability classifies under CWE-190 as an integer overflow in the context of memory allocation operations, where the use of an unchecked length field results in attempting to allocate memory blocks that exceed system limitations.
The operational impact of this vulnerability extends beyond simple denial of service conditions, as it represents a fundamental security weakness that could potentially be exploited to cause daemon crashes and service disruption. Remote attackers capable of sending crafted DHCPv6 packets with malformed option length fields can trigger these integer overflows, resulting in memory allocation failures that cause the affected Dibbler processes to terminate unexpectedly. This creates a persistent denial of service condition that can disrupt network operations and DHCPv6 services, particularly in environments where Dibbler serves as a critical network infrastructure component. The vulnerability affects both server and client implementations, making it particularly concerning for network administrators who rely on Dibbler for dynamic address assignment and network configuration management.
The exploitation of this vulnerability aligns with ATT&CK technique T1499.001 for network denial of service attacks, where adversaries leverage software weaknesses to disrupt services. The integer overflow conditions create a predictable crash scenario that can be reliably reproduced through carefully crafted packet construction, making this vulnerability suitable for automated exploitation. Network defenders should note that this vulnerability impacts the fundamental packet processing capabilities of Dibbler implementations, potentially affecting large-scale deployments where DHCPv6 services are critical for network operations. The vulnerability demonstrates poor input validation practices that violate security best practices and highlights the importance of implementing proper integer overflow protections in network protocol implementations. Organizations should prioritize updating to patched versions of Dibbler, implementing network monitoring for suspicious DHCPv6 traffic patterns, and considering network segmentation to limit the impact of potential exploitation attempts.