CVE-2012-3411 in Dnsmasq
Summary
by MITRE
Dnsmasq before 2.63test1, when used with certain libvirt configurations, replies to requests from prohibited interfaces, which allows remote attackers to cause a denial of service (traffic amplification) via a spoofed DNS query.
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Analysis
by VulDB Data Team • 12/31/2024
The vulnerability identified as CVE-2012-3411 affects Dnsmasq versions prior to 2.63test1 and represents a significant security flaw in DNS and DHCP services that can be exploited for traffic amplification attacks. This issue specifically manifests when Dnsmasq operates in conjunction with certain libvirt configurations, creating a scenario where the service fails to properly restrict its responses to only authorized network interfaces. The flaw stems from inadequate interface validation mechanisms within the DNS query handling process, allowing malicious actors to exploit the service by sending spoofed DNS queries from unauthorized sources.
The technical implementation of this vulnerability involves Dnsmasq's failure to properly verify the source interface of incoming DNS requests when operating alongside libvirt environments. This misconfiguration creates an attack vector where remote adversaries can craft spoofed DNS queries that appear to originate from legitimate network interfaces, bypassing normal access controls and interface restrictions. The vulnerability is categorized under CWE-284, which addresses improper access control mechanisms, and aligns with ATT&CK technique T1498.001 for network denial of service attacks. The flaw essentially allows unauthorized traffic amplification, where a small number of spoofed queries can generate disproportionately large responses, overwhelming network resources and causing service disruption.
The operational impact of this vulnerability extends beyond simple denial of service, as it enables sophisticated traffic amplification attacks that can be leveraged for distributed denial of service campaigns. Attackers can exploit this weakness to amplify their network traffic by sending spoofed DNS queries to vulnerable Dnsmasq instances, causing the service to respond with much larger packets to the spoofed source addresses. This creates a scenario where network bandwidth and processing resources are consumed inefficiently, potentially leading to complete service unavailability for legitimate users. The vulnerability is particularly concerning in virtualized environments where libvirt configurations are commonly deployed, as these setups often involve complex network topologies that increase the attack surface.
Mitigation strategies for CVE-2012-3411 require immediate implementation of software updates to Dnsmasq versions 2.63test1 or later, which contain fixes for the interface validation issues. Network administrators should also implement proper interface binding configurations to restrict Dnsmasq's listening interfaces to only those that are explicitly authorized for DNS services. Additional protective measures include implementing firewall rules to filter DNS traffic based on source addresses and establishing proper network segmentation to prevent unauthorized access to DNS services. The vulnerability demonstrates the importance of proper access control implementation in network services and highlights the need for comprehensive security testing in virtualized environments where multiple services interact through complex network configurations. Organizations should also consider implementing monitoring solutions to detect anomalous DNS traffic patterns that may indicate exploitation attempts.