CVE-2019-6685 in BIG-IP
Summary
by MITRE
On BIG-IP versions 15.0.0-15.0.1.1, 14.1.0-14.1.2.2, 14.0.0-14.0.1, 13.1.0-13.1.3.1, 12.1.0-12.1.5, and 11.5.2-11.6.5.1, users with access to edit iRules are able to create iRules which can lead to an elevation of privilege, configuration modification, and arbitrary system command execution.
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Analysis
by VulDB Data Team • 03/16/2024
The vulnerability identified as CVE-2019-6685 represents a critical privilege escalation flaw within F5 BIG-IP network security appliances that affects multiple version ranges including 15.0.x, 14.1.x, 14.0.x, 13.1.x, 12.1.x, and 11.5.x through 11.6.5.1. This vulnerability specifically targets the iRules functionality which serves as a scripting mechanism for BIG-IP devices to control traffic flow and application delivery. The flaw exists in the validation and execution mechanisms of iRules, creating a pathway for authenticated users with iRules editing permissions to exploit system-level access.
The technical implementation of this vulnerability stems from insufficient input validation and improper privilege handling within the iRules processing engine. When users with appropriate permissions create or modify iRules, the system fails to properly sanitize or restrict the commands that can be executed within the rule context. This design flaw allows malicious iRules to escalate privileges beyond the normal user boundaries, potentially enabling attackers to execute arbitrary system commands with elevated privileges. The vulnerability operates at the application layer and can be exploited through the configuration management interfaces of the BIG-IP system, typically accessible via the web-based configuration utility or api endpoints.
The operational impact of this vulnerability extends far beyond simple privilege escalation, as it provides attackers with complete system control over affected BIG-IP appliances. Successful exploitation can result in unauthorized modification of network configurations, complete system compromise, and potential data exfiltration from critical network infrastructure. Organizations relying on BIG-IP for application delivery and security services face severe risks including denial of service, unauthorized network access, and potential lateral movement within their network environments. The vulnerability particularly affects organizations with complex network architectures where BIG-IP appliances serve as critical traffic controllers and security gateways.
Mitigation strategies for CVE-2019-6685 require immediate implementation of several security measures including applying the latest F5 security patches and hotfixes released to address the vulnerability. Organizations should also implement strict access controls limiting iRules editing permissions to only trusted administrators and establish comprehensive monitoring for suspicious iRule modifications. Network segmentation and least privilege principles should be enforced to minimize the potential impact of any successful exploitation. The vulnerability aligns with CWE-264 permissions, privileges, and access controls, and maps to attack techniques within the ATT&CK framework including privilege escalation and command execution. Regular security audits and vulnerability assessments should be conducted to ensure proper implementation of these mitigations and to identify any potential misconfigurations that could still leave systems vulnerable to similar attacks.