CVE-2018-5744 in BIND
Summary
by MITRE
A failure to free memory can occur when processing messages having a specific combination of EDNS options. Versions affected are: BIND 9.10.7 -> 9.10.8-P1, 9.11.3 -> 9.11.5-P1, 9.12.0 -> 9.12.3-P1, and versions 9.10.7-S1 -> 9.11.5-S3 of BIND 9 Supported Preview Edition. Versions 9.13.0 -> 9.13.6 of the 9.13 development branch are also affected.
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Analysis
by VulDB Data Team • 07/20/2024
The vulnerability identified as CVE-2018-5744 represents a critical memory management flaw within the Berkeley Internet Name Domain (BIND) software suite, specifically affecting versions ranging from 9.10.7 through 9.10.8-P1, 9.11.3 through 9.11.5-P1, 9.12.0 through 9.12.3-P1, and various supported preview editions. This issue manifests when the DNS server processes messages containing a particular combination of EDNS (Extension Mechanisms for DNS) options, creating a condition where allocated memory is not properly released back to the system. The flaw falls under the category of memory leak vulnerabilities, which can be categorized as CWE-401: Improper Release of Memory, according to the Common Weakness Enumeration standards. The vulnerability operates at the application layer of the network stack and specifically targets the DNS message processing functionality that handles extended options.
The technical execution of this vulnerability occurs during the processing of DNS queries that contain specific combinations of EDNS options, particularly those related to DNSSEC and other extended capabilities. When the BIND server encounters such malformed or specially crafted DNS messages, the memory allocation routines fail to properly execute the deallocation process, leading to gradual memory consumption over time. This memory leak can be exploited by malicious actors who continuously send specially crafted DNS queries to the affected server, causing progressive memory exhaustion. The attack vector requires no authentication and can be executed remotely, making it particularly dangerous for publicly accessible DNS servers. The vulnerability demonstrates characteristics consistent with the attack pattern described in the MITRE ATT&CK framework under the technique T1499.002: Network Denial of Service, as it can lead to service disruption through resource exhaustion.
The operational impact of CVE-2018-5744 extends beyond simple resource consumption, as it can lead to complete service unavailability and system instability. When the memory leak accumulates over time, it can cause the DNS server to either crash entirely or become unresponsive, effectively denying service to legitimate DNS queries from clients. This vulnerability is particularly concerning for authoritative DNS servers that handle high volumes of traffic, as the memory exhaustion can occur rapidly under sustained attack conditions. The affected versions represent a significant portion of the BIND 9.x series, meaning that organizations running these versions are exposed to potential exploitation. The vulnerability affects both production and preview editions of BIND, indicating that even experimental or development versions are susceptible to this memory management failure. Organizations may experience cascading effects where the DNS service disruption impacts dependent applications and services that rely on proper DNS resolution. The cumulative nature of the memory leak means that the impact may not be immediately apparent but can grow progressively over time, making it difficult to diagnose and potentially allowing attackers to maintain persistent resource exhaustion conditions. The vulnerability also demonstrates the importance of proper memory management practices in network services, as even small flaws in resource handling can lead to significant operational disruptions and security implications.