CVE-2014-0486 in DNS
Summary
by MITRE
Knot DNS before 1.5.2 allows remote attackers to cause a denial of service (application crash) via a crafted DNS message.
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Analysis
by VulDB Data Team • 02/24/2023
The vulnerability identified as CVE-2014-0486 affects Knot DNS versions prior to 1.5.2, representing a critical denial of service flaw that enables remote attackers to crash the DNS server application. This vulnerability resides within the DNS message processing functionality of the Knot DNS resolver, where improper handling of malformed DNS packets leads to application instability and potential system unavailability. The flaw specifically manifests when the DNS server encounters crafted DNS messages that contain malformed or unexpected data structures, causing the application to terminate unexpectedly and disrupting DNS resolution services for legitimate clients. Such a vulnerability directly impacts the availability aspect of the DNS infrastructure, as it can be exploited by attackers without requiring authentication or privileged access to the system.
The technical root cause of this vulnerability stems from inadequate input validation and error handling within the DNS message parsing components of Knot DNS. When processing incoming DNS queries or responses, the software fails to properly validate the structure and content of DNS packets before attempting to parse or process them. This lack of robust validation allows attackers to craft specially formatted DNS messages that trigger memory corruption or undefined behavior within the application's processing pipeline. The vulnerability aligns with CWE-129, which describes improper validation of input boundaries, and CWE-248, which addresses an exception not caught by the application. The flaw demonstrates characteristics consistent with buffer overflows and memory management issues that commonly occur when applications fail to properly validate input data before processing.
From an operational perspective, this vulnerability presents significant risk to organizations relying on Knot DNS for their domain name resolution services. Attackers can exploit this weakness to repeatedly crash the DNS server, leading to extended periods of service unavailability that can affect thousands of users or systems dependent on the affected DNS infrastructure. The impact extends beyond simple service disruption as it can cause cascading failures in network services that depend on DNS resolution, potentially affecting email services, web applications, and other internet-dependent systems. The vulnerability's remote exploitation capability means that attackers can target affected systems from anywhere on the internet without requiring physical access or network proximity, making it particularly dangerous in production environments where DNS servers are exposed to public networks.
Organizations should prioritize immediate remediation by upgrading to Knot DNS version 1.5.2 or later, which includes proper input validation and error handling mechanisms that prevent the exploitation of this vulnerability. System administrators should also implement network-level mitigations such as DNS query filtering and rate limiting to reduce the impact of potential attacks while awaiting patch deployment. The vulnerability's classification under the ATT&CK framework would place it within the T1499 category for network denial of service, with potential connections to T1071 for application layer protocols and T1566 for credential harvesting through service disruption. Additional defensive measures include implementing intrusion detection systems that can identify malformed DNS traffic patterns and establishing monitoring procedures to detect unusual application crash events that may indicate exploitation attempts.