CVE-2022-0635 in BIND
Summary
by MITRE • 03/23/2022
Versions affected: BIND 9.18.0 When a vulnerable version of named receives a series of specific queries, the named process will eventually terminate due to a failed assertion check.
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Analysis
by VulDB Data Team • 11/19/2025
The vulnerability in BIND 9.18.0 represents a critical denial of service condition that can be exploited through carefully crafted query sequences. This issue manifests as a failed assertion check within the named process, ultimately leading to process termination and complete service unavailability. The flaw exists in the query processing logic where specific patterns of DNS queries can trigger an internal assertion failure, causing the authoritative name server to crash and restart. This represents a classic software reliability issue that can be leveraged by attackers to disrupt DNS services and potentially cause cascading failures across dependent systems.
The technical nature of this vulnerability aligns with CWE-617, which addresses reachable assertions in software systems where program execution reaches an assertion that fails, causing abnormal termination. The flaw demonstrates how seemingly benign input processing can lead to catastrophic system failure when assertion checks are not properly validated against malicious or edge-case inputs. In the context of DNS infrastructure, this vulnerability directly impacts the stability and availability of authoritative name servers that form the backbone of internet domain resolution services.
From an operational perspective, the impact extends far beyond simple service disruption as DNS outages can affect thousands of applications and users simultaneously. The vulnerability's exploitation requires only a series of specific queries to be sent to the vulnerable named process, making it particularly dangerous in environments where DNS servers are exposed to untrusted networks or when attackers can submit queries through open resolvers or recursive name servers. This scenario creates significant risk for organizations that rely on BIND for their authoritative DNS services, as the attack can be executed with minimal resources and technical expertise.
The mitigation strategy for this vulnerability requires immediate deployment of patched versions of BIND 9.18.0 and subsequent releases that address the assertion failure in query processing. Organizations should implement network segmentation to limit access to authoritative DNS servers and consider deploying monitoring solutions that can detect unusual query patterns that may indicate exploitation attempts. Additionally, implementing rate limiting and query filtering mechanisms can help reduce the effectiveness of potential attacks while patches are being deployed. The vulnerability also highlights the importance of proper input validation and assertion handling in critical infrastructure software, reinforcing security principles outlined in the mitre ATT&CK framework under the execution and privilege escalation domains where service disruption can lead to broader system compromise.