CVE-2003-0858 in Quagga
Summary
by MITRE
Zebra 0.93b and earlier, and quagga before 0.95, allows local users to cause a denial of service by sending spoofed messages as other users to the kernel netlink interface.
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Analysis
by VulDB Data Team • 05/17/2019
The vulnerability identified as CVE-2003-0858 affects routing software implementations including Zebra version 0.93b and earlier, and Quagga before version 0.95. This flaw resides in the handling of messages transmitted through the kernel netlink interface, which serves as a communication channel between user-space routing daemons and the kernel's routing table management system. The issue stems from insufficient validation of message sources, allowing malicious local users to craft and send forged messages that appear to originate from legitimate users or system processes.
The technical implementation of this vulnerability exploits the trust relationship between routing daemons and the kernel netlink interface. When routing software processes messages through this interface, it typically relies on the integrity of the message source identification without sufficient verification mechanisms. Local attackers can leverage this weakness by crafting specially formatted netlink messages that spoof the identity of other users or system components, effectively bypassing normal access controls and authentication checks. This spoofing capability enables attackers to manipulate routing information or disrupt normal routing operations through the kernel interface.
The operational impact of this vulnerability manifests as a denial of service condition that can severely compromise network infrastructure stability. When spoofed messages are processed by the routing daemon, they can cause unexpected behavior including routing table corruption, daemon crashes, or complete service unavailability. The vulnerability is particularly dangerous because it operates at the kernel level through the netlink interface, making it difficult to detect and mitigate. Network administrators may observe sudden routing failures, connectivity issues, or routing daemon restarts without clear indication of the root cause, as the malicious activity appears to originate from legitimate system processes.
From a cybersecurity perspective, this vulnerability aligns with CWE-284, which addresses improper access control in software systems. The flaw represents a classic case of insufficient input validation and trust model exploitation, where the system assumes message authenticity without proper verification. The attack vector maps to the MITRE ATT&CK framework under T1059 for command and scripting interpreter and T1498 for network denial of service, as attackers can leverage the compromised routing infrastructure to disrupt network services. The local privilege requirement means that exploitation does not require network access, making it particularly concerning for systems where local user access is not strictly controlled.
The recommended mitigation strategies include immediate deployment of patched versions of Zebra and Quagga software, implementing proper message validation mechanisms at the netlink interface level, and applying restrictive access controls to routing daemon processes. System administrators should also consider implementing monitoring solutions that can detect anomalous netlink message patterns and establish network segmentation to limit potential impact. The vulnerability underscores the importance of secure coding practices in kernel-level interfaces and demonstrates the critical need for proper input validation and source authentication mechanisms in network infrastructure software. Organizations should also review their access control policies and ensure that local user privileges are properly managed to prevent unauthorized access to routing services that could be exploited through this vulnerability.