CVE-2023-41253 in BIG-IP
Summary
by MITRE • 10/25/2023
When on BIG-IP DNS or BIG-IP LTM enabled with DNS Services License, and a TSIG key is created, it is logged in plaintext in the audit log. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
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Analysis
by VulDB Data Team • 10/28/2023
This vulnerability exists within F5 Networks BIG-IP systems when configured with DNS Services License and utilizing TSIG key functionality. The flaw represents a critical security oversight in the system's audit logging mechanism where sensitive authentication credentials are stored in plaintext format rather than being properly obfuscated or encrypted. The vulnerability affects systems running BIG-IP DNS or BIG-IP LTM platforms that have DNS Services License enabled, making it particularly concerning for organizations relying on these platforms for critical infrastructure services.
The technical implementation flaw stems from improper handling of TSIG key information within the audit logging subsystem. When TSIG keys are created and used for DNS transactions, the system automatically logs these credentials to audit logs without any form of cryptographic protection or sanitization. This plaintext exposure occurs at the point of key creation and persists throughout the key's lifecycle within the audit trail. The vulnerability manifests as a failure to apply proper credential protection mechanisms that should be implemented according to security best practices and industry standards such as those outlined in CWE-522 which addresses insufficiently protected credentials.
The operational impact of this vulnerability is severe and multifaceted. An attacker with access to audit logs or system administrators with appropriate privileges can directly extract TSIG keys in plaintext format, enabling them to forge DNS requests, manipulate DNS records, and potentially gain unauthorized access to DNS services. This compromises the integrity and authenticity of DNS communications, potentially leading to DNS spoofing, cache poisoning, and broader network infiltration attempts. The exposure of these keys undermines the fundamental security model of DNS security mechanisms, as TSIG keys are designed to provide authenticated denial of existence and secure dynamic updates. The vulnerability also creates a persistent risk as these plaintext credentials remain accessible in audit logs indefinitely, providing attackers with long-term access capabilities.
Organizations should implement immediate mitigations including restricting access to audit logs, implementing additional logging controls, and ensuring that TSIG keys are managed through secure credential management systems. The recommended approach involves configuring audit log retention policies to minimize exposure windows, implementing network segmentation to limit access to sensitive logs, and ensuring that system administrators follow principle of least privilege. Security controls should include monitoring for unauthorized access attempts to audit logs and implementing automated alerting for credential exposure events. According to ATT&CK framework, this vulnerability maps to T1566.002 (Phishing for Information) and T1078 (Valid Accounts) as attackers can leverage the exposed credentials to establish persistent access. Organizations should also consider implementing additional controls such as regular audit log reviews, enhanced access controls, and credential rotation procedures to reduce the risk associated with this exposure. The vulnerability highlights the importance of proper credential handling in security logging systems and aligns with security standards emphasizing the protection of sensitive data in audit trails.