CVE-2017-14339 in YADIFA
Summary
by MITRE
The DNS packet parser in YADIFA before 2.2.6 does not check for the presence of infinite pointer loops, and thus it is possible to force it to enter an infinite loop. This can cause high CPU usage and makes the server unresponsive.
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Analysis
by VulDB Data Team • 11/18/2019
The vulnerability identified as CVE-2017-14339 affects the YADIFA DNS server software version 2.2.5 and earlier, representing a critical denial of service weakness in the DNS packet parsing functionality. This flaw stems from inadequate validation within the DNS message processing pipeline, specifically concerning the handling of pointer references within DNS resource records. The vulnerability manifests when the DNS parser encounters malformed DNS packets containing circular pointer references that create infinite loops during packet processing. This issue directly relates to CWE-835, which categorizes infinite loops or iterations as a significant weakness in software design that can lead to system resource exhaustion. The absence of proper loop detection mechanisms in the YADIFA parser allows malicious actors to craft specially formatted DNS packets that contain recursive pointer structures, causing the server to continuously follow these pointers without termination.
The operational impact of this vulnerability extends beyond simple service disruption, creating substantial security implications for network infrastructure relying on YADIFA for DNS services. When exploited, the infinite pointer loop causes the DNS server to consume excessive CPU resources as it repeatedly processes the same pointer references, ultimately leading to complete server unresponsiveness. This behavior creates a denial of service condition that can affect all DNS resolution requests until the server is manually restarted or the problematic packets are filtered. The vulnerability is particularly concerning in environments where DNS servers handle high volumes of traffic, as the resource exhaustion can occur rapidly and with minimal effort from an attacker. Network administrators may observe sustained high CPU utilization on affected systems, making it difficult to distinguish between legitimate traffic spikes and malicious exploitation attempts.
The exploitation of this vulnerability aligns with techniques described in the ATT&CK framework under the T1499 category for network denial of service attacks, where adversaries leverage software weaknesses to exhaust system resources. The attack vector requires sending specifically crafted DNS packets to the vulnerable server, which can be accomplished through various methods including DNS amplification attacks or direct packet injection. Organizations running YADIFA versions prior to 2.2.6 face significant risk exposure, particularly in environments where DNS servers are not properly segmented or where access controls are insufficient to prevent unauthorized packet injection. The vulnerability demonstrates a fundamental flaw in the server's input validation mechanisms, highlighting the importance of robust parsing routines that can detect and terminate malformed data processing sequences. Security teams should consider implementing network-level mitigations such as DNS packet filtering rules that can detect and block malformed DNS responses containing suspicious pointer structures, while also planning for immediate patch deployment to address the root cause.
Mitigation strategies for CVE-2017-14339 should prioritize immediate software updates to YADIFA version 2.2.6 or later, which includes proper pointer loop detection and termination mechanisms. Organizations should also implement network monitoring solutions capable of detecting unusual CPU utilization patterns that may indicate exploitation attempts, alongside deploying intrusion detection systems that can identify malformed DNS packets with circular pointer references. The implementation of rate limiting and connection tracking mechanisms can help reduce the impact of potential attacks by limiting the number of malformed packets that can be processed within a given timeframe. Additionally, network segmentation and access control policies should be strengthened to limit direct exposure of DNS servers to untrusted networks, reducing the attack surface available to potential adversaries. Regular security assessments and penetration testing should be conducted to verify that the patch has been properly applied and that no other similar vulnerabilities exist within the DNS infrastructure.