CVE-2006-2276 in Quagga
Summary
by MITRE
bgpd in Quagga 0.98 and 0.99 before 20060504 allows local users to cause a denial of service (CPU consumption) via a certain sh ip bgp command entered in the telnet interface.
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Analysis
by VulDB Data Team • 06/18/2019
The vulnerability identified as CVE-2006-2276 affects the bgpd component of Quagga routing software versions 0.98 and 0.99 prior to the 20060504 release. This issue represents a denial of service weakness that specifically targets the Border Gateway Protocol daemon within the Quagga suite, which is a widely used open-source routing software implementation. The vulnerability manifests when a local user executes a particular sh ip bgp command through the telnet interface, leading to excessive cpu consumption that can ultimately result in system unresponsiveness or complete denial of service for routing services.
The technical flaw resides in the improper handling of specific command inputs within the bgpd process when accessed via telnet interface. The sh ip bgp command, which is designed to display routing table information, contains a processing logic error that causes the daemon to enter an infinite loop or consume excessive computational resources when parsing certain malformed or specially crafted input parameters. This processing anomaly directly violates the expected behavior of network management commands and demonstrates inadequate input validation within the command parsing subsystem. The vulnerability operates at the application layer and leverages the telnet interface as the attack vector, making it particularly concerning as it requires only local access to exploit.
From an operational impact perspective, this vulnerability poses significant risks to network infrastructure reliability and availability. When exploited, the excessive cpu consumption can cause the bgpd process to monopolize system resources, potentially affecting other routing protocols and network services running on the same system. Network administrators may experience complete loss of routing control during the attack, as the system becomes unresponsive to legitimate commands and network traffic can be disrupted. The vulnerability's local nature means that any user with access to the telnet interface can trigger the denial of service condition, potentially allowing both accidental and malicious exploitation that could compromise network operations and availability.
The vulnerability aligns with CWE-400, which classifies the issue as an Uncontrolled Resource Consumption or 'Resource Exhaustion' weakness, specifically manifesting as a denial of service condition through excessive cpu usage. From an ATT&CK framework perspective, this vulnerability maps to the T1499.004 technique for Network Denial of Service, and potentially to T1059.005 for Command and Scripting Interpreter - PowerShell, though the latter is less directly applicable given the telnet interface context. The attack surface is limited to systems where Quagga is installed with telnet access enabled, but this includes many network devices where local administrative access is commonly available, making the vulnerability particularly concerning for enterprise network environments where such access may be more prevalent than anticipated.
Mitigation strategies should focus on immediate patch application to Quagga versions released after 20060504, which contain the necessary fixes for the command parsing logic. System administrators should also implement access controls to limit telnet access to trusted users only, and consider disabling telnet interfaces in favor of more secure SSH-based access methods. Additional monitoring should be implemented to detect unusual cpu consumption patterns in bgpd processes, and network administrators should establish procedures for rapid response to potential exploitation attempts. The vulnerability serves as a reminder of the importance of input validation and resource management in network service implementations, particularly for critical routing components that must maintain high availability and performance under all operational conditions.