CVE-2017-3136 in BIND
Summary
by MITRE
A query with a specific set of characteristics could cause a server using DNS64 to encounter an assertion failure and terminate. An attacker could deliberately construct a query, enabling denial-of-service against a server if it was configured to use the DNS64 feature and other preconditions were met. Affects BIND 9.8.0 -> 9.8.8-P1, 9.9.0 -> 9.9.9-P6, 9.9.10b1->9.9.10rc1, 9.10.0 -> 9.10.4-P6, 9.10.5b1->9.10.5rc1, 9.11.0 -> 9.11.0-P3, 9.11.1b1->9.11.1rc1, 9.9.3-S1 -> 9.9.9-S8.
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Analysis
by VulDB Data Team • 11/29/2022
The vulnerability identified as CVE-2017-3136 represents a critical denial-of-service weakness within the Berkeley Internet Name Domain software version 9.8.0 through 9.11.1rc1, specifically affecting systems configured with DNS64 functionality. This flaw manifests when a specially crafted DNS query triggers an assertion failure within the BIND server process, leading to abrupt termination of the service. The vulnerability operates at the application layer of the network stack, exploiting a fundamental processing error in how the software handles certain DNS query patterns. DNS64 is a DNS protocol extension designed to enable IPv6-only networks to communicate with IPv4 services by synthesizing IPv6 addresses from IPv4 addresses through DNS resolution, making this vulnerability particularly concerning for networks implementing dual-stack communication.
The technical implementation of this vulnerability stems from insufficient input validation within the DNS64 processing module of BIND. When a malicious actor crafts a query with specific characteristics that meet predetermined conditions, the software's internal assertion mechanisms fail to properly handle the malformed input, causing the server to crash and terminate its operations. This assertion failure occurs during the normal processing of DNS queries, meaning legitimate traffic could be disrupted by the malicious query alone. The flaw does not require authentication or elevated privileges to exploit, making it particularly dangerous as any network entity capable of sending DNS queries can potentially trigger the vulnerability. The vulnerability is classified under CWE-248, which identifies "Uncaught Exception" as the underlying weakness, and aligns with ATT&CK technique T1499.004 for network denial-of-service attacks. The affected versions span multiple release branches of BIND, indicating this was a widespread issue that required coordinated patching across various software versions.
The operational impact of CVE-2017-3136 extends beyond simple service disruption to potentially compromise network availability and reliability for organizations relying on DNS64 functionality. When exploited, the vulnerability can cause cascading failures in network infrastructure, particularly affecting systems where DNS64 serves as a critical bridge between IPv4 and IPv6 communications. Organizations utilizing DNS64 for dual-stack network operations face significant risk as this vulnerability can be triggered by a single malicious query, potentially affecting all users serviced by the compromised DNS server. The vulnerability's exploitation capability makes it attractive to attackers seeking to disrupt network services, as the impact is immediate and severe without requiring complex attack chains or privileged access. Network administrators must consider the broader implications for their infrastructure, as DNS servers are fundamental to network operations and any disruption can affect numerous dependent services and applications.
Mitigation strategies for CVE-2017-3136 primarily involve applying the appropriate security patches released by the Internet Systems Consortium for affected BIND versions. Organizations should immediately upgrade to patched versions of BIND, specifically targeting releases that include fixes for DNS64 processing anomalies. The patch addresses the core assertion failure by implementing proper input validation and exception handling within the DNS64 processing code. Additionally, network administrators should consider implementing query rate limiting and filtering mechanisms to reduce the effectiveness of potential exploitation attempts. Monitoring systems should be configured to detect unusual query patterns that might indicate exploitation attempts, particularly focusing on queries that exhibit the specific characteristics triggering the vulnerability. For environments where immediate patching is not feasible, temporary workarounds such as disabling DNS64 functionality or implementing restrictive firewall rules can provide interim protection. The vulnerability's classification under CWE-248 and its alignment with ATT&CK techniques highlight the importance of robust error handling and input validation practices in DNS server implementations. Organizations should also review their DNS server configurations to ensure that DNS64 is only enabled where absolutely necessary, reducing the attack surface for this and similar vulnerabilities.