CVE-2019-6621 in BIG-IP
Summary
by MITRE
On BIG-IP 14.1.0-14.1.0.5, 14.0.0-14.0.0.5, 13.0.0-13.1.1.4, 12.1.0-12.1.4.1, 11.6.1-11.6.3.4, and 11.5.1-11.5.8 and BIG-IQ 6.0.0-6.1.0 and 5.1.0-5.4.0, an undisclosed iControl REST worker is vulnerable to command injection by an admin/resource admin user. This issue impacts both iControl REST and tmsh implementations.
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Analysis
by VulDB Data Team • 10/15/2023
The vulnerability identified as CVE-2019-6621 represents a critical command injection flaw within F5 Networks BIG-IP and BIG-IQ platforms that affects multiple version ranges across different product lines. This security weakness resides in the iControl REST worker component, which serves as a critical interface for remote management and configuration of F5 devices. The vulnerability is particularly concerning because it allows authenticated users with administrative privileges to execute arbitrary commands on the underlying system, effectively providing a backdoor for malicious actors who have gained access to legitimate admin accounts.
The technical implementation of this vulnerability stems from insufficient input validation and sanitization within the iControl REST worker processes that handle administrative requests. When administrative users submit commands through the REST API or tmsh interface, the system fails to properly validate or escape user-supplied input parameters, creating opportunities for attackers to inject malicious commands that bypass normal security controls. This flaw operates at the application layer and specifically targets the authentication and authorization mechanisms that should prevent unauthorized command execution. The vulnerability affects both the REST API implementation and the traditional tmsh command-line interface, making it particularly dangerous as attackers can exploit either interface depending on their access method and target system configuration.
The operational impact of this vulnerability extends far beyond simple privilege escalation, as it enables full system compromise for authenticated administrators. Attackers who exploit this vulnerability can execute arbitrary code with the highest system privileges, potentially leading to complete system takeover, data exfiltration, and lateral movement within networks where F5 devices are deployed. The affected versions span multiple major releases, indicating this was a persistent flaw that affected a significant portion of F5 deployments. Organizations using these vulnerable versions face risks of unauthorized access, system manipulation, and potential data breaches that could compromise critical network infrastructure and sensitive organizational data.
Security professionals should implement immediate mitigation strategies including applying the latest F5 security patches and updates, reviewing administrative access controls, and implementing network segmentation to limit exposure of vulnerable devices. The vulnerability aligns with CWE-77 and CWE-94 categories related to command injection and code execution flaws, and can be mapped to ATT&CK techniques involving privilege escalation and execution through valid accounts. Organizations should also consider implementing additional monitoring and logging of administrative activities, as well as conducting thorough security audits of their F5 device configurations to identify and remediate similar vulnerabilities that may exist in other components of their network infrastructure.