CVE-2016-4049 in Quagga
Summary
by MITRE
The bgp_dump_routes_func function in bgpd/bgp_dump.c in Quagga does not perform size checks when dumping data, which might allow remote attackers to cause a denial of service (assertion failure and daemon crash) via a large BGP packet.
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Analysis
by VulDB Data Team • 08/22/2022
The vulnerability identified as CVE-2016-4049 resides within the bgp_dump_routes_func function located in the bgpd/bgp_dump.c file of the Quagga routing software suite. This critical flaw represents a classic buffer overflow condition that occurs when the software fails to validate the size of incoming BGP packets before processing them. The issue specifically affects the BGP daemon component responsible for handling Border Gateway Protocol routing information exchange between network devices. When a malicious actor sends a specially crafted BGP packet with excessive data payload, the function attempts to dump this information without proper size validation, creating a scenario where the software's internal assertion mechanisms trigger failures. This vulnerability demonstrates a fundamental lack of input sanitization and bounds checking that is essential for network daemon applications handling external protocol data. The flaw directly relates to CWE-129, which addresses insufficient bounds checking, and represents a significant weakness in the software's defensive programming practices. BGP is a critical protocol for internet routing operations, making any vulnerability in BGP daemon implementations particularly dangerous as it can disrupt core internet infrastructure.
The operational impact of this vulnerability extends beyond simple denial of service conditions to potentially compromise entire network routing systems. When the daemon crashes due to assertion failures, it creates a cascading effect that can disrupt routing information exchange between network devices, leading to routing black holes, packet loss, and overall network instability. Network administrators may experience unexpected service interruptions as routing daemons restart and re-establish connections, potentially causing temporary network outages. The remote exploitation aspect means that attackers can trigger this condition from outside the network perimeter without requiring local access or authentication credentials. This makes the vulnerability particularly attractive to threat actors seeking to disrupt network operations or conduct broader attacks against internet infrastructure. The crash occurs during normal BGP packet processing, meaning that legitimate network traffic can be used as a vector for this attack, making detection and prevention more challenging. From an attack methodology perspective, this vulnerability aligns with ATT&CK technique T1499.004, which covers network disruption attacks through service availability, and represents a classic example of how protocol implementation flaws can be weaponized for denial of service attacks against critical network infrastructure.
Mitigation strategies for CVE-2016-4049 should focus on immediate software updates and implementation of defensive network controls. The primary solution involves applying patches released by the Quagga development team that include proper size validation and bounds checking within the bgp_dump_routes_func function. Organizations should also implement BGP monitoring systems that can detect unusual packet sizes or patterns that might indicate exploitation attempts. Network segmentation and access control measures can help limit the attack surface by restricting which systems can receive BGP updates from external sources. Implementing BGP protocol security extensions such as BGPsec or Route Origin Authorization can provide additional protection layers against malformed BGP packets. From a defensive programming standpoint, this vulnerability highlights the importance of following secure coding practices including input validation, bounds checking, and proper error handling in network daemon applications. The incident underscores the necessity of thorough code review processes and automated testing that includes stress testing with oversized data packets to identify similar conditions before they can be exploited in production environments. Regular security assessments of routing infrastructure components should include evaluation of protocol implementation vulnerabilities to ensure that critical network services maintain their reliability and resilience against both accidental and intentional disruptions.