CVE-2022-41787 in BIG-IP
Summary
by MITRE • 10/20/2022
In BIG-IP versions 17.0.x before 17.0.0.1, 16.1.x before 16.1.3.1, 15.1.x before 15.1.6.1, 14.1.x before 14.1.5.1, and 13.1.x before 13.1.5.1, when DNS profile is configured on a virtual server with DNS Express enabled, undisclosed DNS queries with DNSSEC can cause TMM to terminate.
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Analysis
by VulDB Data Team • 10/20/2022
The vulnerability identified as CVE-2022-41787 affects F5 BIG-IP appliances running specific versions of the BIG-IP system software where DNS profiles are configured with DNS Express enabled. This issue represents a denial of service condition that can be triggered through crafted DNS queries containing DNSSEC information, potentially leading to complete service disruption for affected virtual servers. The vulnerability specifically targets the Traffic Management Microkernel (TMM) process which handles network traffic processing, making it particularly critical for network infrastructure security. According to F5's security advisory, the flaw manifests when the system encounters undisclosed DNS queries with DNSSEC data, causing the TMM component to terminate unexpectedly and requiring manual intervention to restore service.
The technical mechanism behind this vulnerability involves the interaction between the DNS profile configuration and the DNS Express feature within the BIG-IP system. When DNS Express is enabled on a virtual server, the system processes DNS queries through a specialized DNS handling mechanism that can be exploited by malicious actors. The termination occurs specifically when processing DNS queries that contain DNSSEC records but are otherwise not properly validated or handled by the system's DNS processing logic. This behavior aligns with CWE-400, which categorizes the vulnerability as an unspecified error handling issue where the system fails to properly manage exceptional conditions during DNS query processing. The flaw essentially creates an unhandled exception scenario where the TMM process crashes rather than gracefully handling malformed or unexpected DNSSEC data.
The operational impact of CVE-2022-41787 extends beyond simple service disruption to potentially compromise network availability and business continuity. Organizations relying on BIG-IP appliances for DNS services, load balancing, or application delivery face significant risk when this vulnerability is exploited, as the termination of TMM processes can affect multiple virtual servers and applications simultaneously. The vulnerability can be exploited remotely without authentication, making it particularly dangerous in environments where external access to DNS services is permitted. From an attack perspective, this issue maps to ATT&CK technique T1499.004 which covers network denial of service attacks, and T1595.001 which involves reconnaissance for vulnerabilities in network infrastructure. The impact is exacerbated by the fact that the vulnerability affects multiple major versions of the BIG-IP software, requiring organizations to assess and patch across several release lines.
Mitigation strategies for CVE-2022-41787 primarily involve applying the official security patches provided by F5, which address the underlying DNS processing logic to properly handle DNSSEC queries without causing system termination. Organizations should prioritize patching all affected BIG-IP versions according to F5's security advisory guidance, with particular attention to the specific version ranges mentioned in the vulnerability description. Additional protective measures include implementing network segmentation to limit access to DNS services, monitoring for unusual DNS query patterns that might indicate exploitation attempts, and configuring appropriate logging to detect when DNS queries trigger system instability. Network administrators should also consider temporarily disabling DNS Express functionality on affected virtual servers until patches can be deployed, though this may impact performance for DNS-intensive applications. The vulnerability underscores the importance of maintaining up-to-date security patches for critical infrastructure components and demonstrates how seemingly minor configuration elements like DNS profile settings can create significant security risks when combined with specific processing logic flaws.