CVE-2012-0249 in Quagga
Summary
by MITRE
Buffer overflow in the ospf_ls_upd_list_lsa function in ospf_packet.c in the OSPFv2 implementation in ospfd in Quagga before 0.99.20.1 allows remote attackers to cause a denial of service (assertion failure and daemon exit) via a Link State Update (aka LS Update) packet that is smaller than the length specified in its header.
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Analysis
by VulDB Data Team • 12/24/2024
The vulnerability identified as CVE-2012-0249 represents a critical buffer overflow flaw within the OSPFv2 routing protocol implementation in Quagga networking software. This issue specifically affects the ospf_ls_upd_list_lsa function located in the ospf_packet.c file, which processes Link State Update packets that are fundamental to OSPFv2 operation. The flaw occurs when the daemon receives a malformed LS Update packet where the actual packet data is smaller than the length field specified in the packet header, creating a scenario where memory boundaries are exceeded during packet processing.
The technical exploitation of this vulnerability stems from inadequate input validation within the OSPF daemon's packet parsing logic. When Quagga's ospfd process encounters an LS Update packet with a mismatch between the declared packet length and the actual data available, the ospf_ls_upd_list_lsa function fails to properly handle this discrepancy. This condition triggers an assertion failure within the software's memory management system, causing the daemon to terminate abruptly and resulting in a denial of service condition that affects the entire routing functionality of the affected network device.
From an operational impact perspective, this vulnerability presents a significant risk to network stability and availability, particularly in environments where OSPF routing protocols are heavily utilized. Network administrators may experience unexpected daemon crashes and routing table inconsistencies that can propagate across the entire network infrastructure. The vulnerability's remote exploitability means that malicious actors can trigger the denial of service condition from outside the network perimeter without requiring authentication, making it particularly dangerous in production environments where routing stability is paramount for network operations.
The flaw aligns with CWE-121, which describes stack-based buffer overflow conditions, and demonstrates how improper bounds checking in network protocol implementations can lead to system instability. This vulnerability also maps to ATT&CK technique T1499.004, which covers network denial of service attacks, as it enables adversaries to disrupt network communications through daemon termination. The issue specifically affects Quagga versions prior to 0.99.20.1, indicating that proper input validation and memory boundary checks were not adequately implemented in earlier releases of this widely-used routing software.
Organizations should immediately implement mitigations including updating to Quagga version 0.99.20.1 or later, which contains the necessary patches to validate packet lengths before processing. Network segmentation strategies can help limit the impact of potential exploitation attempts, while monitoring systems should be configured to detect daemon restarts or unusual routing behavior that may indicate exploitation. Additionally, implementing ingress filtering and packet validation mechanisms at network boundaries can provide additional defense in depth against this specific attack vector that targets the OSPF protocol implementation within routing daemons.