CVE-2016-6411 in FirePOWER Management Center
Summary
by MITRE
Cisco Firepower Management Center and FireSIGHT System Software 6.0.1 mishandle comparisons between URLs and X.509 certificates, which allows remote attackers to bypass intended do-not-decrypt settings via a crafted URL, aka Bug ID CSCva50585.
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Analysis
by VulDB Data Team • 09/20/2022
The vulnerability identified as CVE-2016-6411 affects Cisco Firepower Management Center and FireSIGHT System Software version 6.0.1, presenting a critical security flaw in the handling of URL and X.509 certificate comparisons. This weakness resides in the software's decryption policies mechanism, where improper validation occurs during the evaluation of secure communication protocols. The flaw specifically manifests when the system attempts to compare URLs against X.509 certificates to determine whether traffic should be decrypted for inspection, creating a potential bypass scenario for security controls.
The technical implementation error stems from inadequate input validation and comparison logic within the encryption inspection framework. When processing network traffic, the system fails to properly validate the relationship between Uniform Resource Locators and digital certificates, allowing attackers to craft malicious URLs that can circumvent the intended do-not-decrypt settings. This vulnerability operates at the application layer and leverages the software's trust model, where legitimate certificate validation procedures are bypassed through crafted inputs that exploit the comparison algorithm's weaknesses. The issue represents a classic case of improper input validation that can be classified under CWE-254, which encompasses security weaknesses related to improper input validation.
The operational impact of this vulnerability extends beyond simple bypass scenarios, as it fundamentally undermines the security posture of organizations relying on Cisco Firepower systems for network protection. Remote attackers can exploit this weakness to gain unauthorized access to encrypted traffic that should remain protected, potentially exposing sensitive data, credentials, and communication channels. The vulnerability enables attackers to perform man-in-the-middle attacks against secure communications, undermining the integrity of the security infrastructure and potentially allowing for further lateral movement within the network. This weakness can be particularly dangerous in enterprise environments where the system is responsible for monitoring and controlling encrypted traffic flows, as it allows attackers to avoid detection by security appliances that are specifically designed to inspect and control such traffic.
Organizations affected by CVE-2016-6411 should prioritize immediate remediation through official Cisco patches and updates, as the vulnerability provides attackers with a straightforward method for bypassing security controls. The mitigation strategy should include applying the latest software releases from Cisco that address the comparison logic flaws in the certificate validation process. Network administrators should also consider implementing additional monitoring and anomaly detection measures to identify potential exploitation attempts. From a defensive perspective, this vulnerability aligns with tactics described in the MITRE ATT&CK framework under T1071.004 for application layer protocol tunneling and T1566 for phishing attacks, as it enables attackers to bypass security controls that would typically prevent such attacks. The vulnerability demonstrates the critical importance of proper cryptographic protocol implementation and validation in security appliances, as it represents a failure in the fundamental trust mechanisms that secure communication systems rely upon.