CVE-2015-6435 in FX-OS
Summary
by MITRE
An unspecified CGI script in Cisco FX-OS before 1.1.2 on Firepower 9000 devices and Cisco Unified Computing System (UCS) Manager before 2.2(4b), 2.2(5) before 2.2(5a), and 3.0 before 3.0(2e) allows remote attackers to execute arbitrary shell commands via a crafted HTTP request, aka Bug ID CSCur90888.
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Analysis
by VulDB Data Team • 07/06/2022
The vulnerability identified as CVE-2015-6435 represents a critical remote code execution flaw affecting Cisco Firepower 9000 devices running FX-OS versions prior to 1.1.2 and Cisco UCS Manager software versions before specific patches. This vulnerability resides within an unspecified CGI script component that processes HTTP requests, creating an attack surface where malicious actors can inject and execute arbitrary shell commands on affected systems. The flaw essentially allows attackers to bypass normal authentication mechanisms and directly manipulate the underlying operating system through crafted web requests.
The technical exploitation of this vulnerability occurs through the manipulation of HTTP request parameters that are processed by the vulnerable CGI script. When the affected system receives a specially crafted HTTP request containing malicious input, the CGI script fails to properly validate or sanitize the input before processing it as part of shell command execution. This input validation failure creates a classic command injection vulnerability that aligns with CWE-77 and CWE-94 categories, where user-supplied data is directly incorporated into system commands without adequate sanitization. The vulnerability specifically maps to the ATT&CK technique T1059.001 for Command and Scripting Interpreter, as attackers can execute arbitrary commands through the web interface.
The operational impact of CVE-2015-6435 is severe and far-reaching across enterprise security infrastructure. Attackers who successfully exploit this vulnerability can gain full administrative control over affected Firepower 9000 appliances and UCS Manager systems, potentially leading to complete network compromise. The remote nature of the attack means that adversaries do not require physical access or local network presence to exploit the vulnerability, making it particularly dangerous for organizations with exposed management interfaces. This vulnerability can enable attackers to establish persistent backdoors, exfiltrate sensitive data, modify network security policies, and use compromised devices as launch points for lateral movement within the network. Organizations relying on Cisco Firepower and UCS solutions face significant risk of unauthorized access and potential data breaches.
Mitigation strategies for CVE-2015-6435 require immediate implementation of firmware and software updates from Cisco to address the specific vulnerabilities in FX-OS and UCS Manager versions. Organizations should also implement network segmentation to limit access to management interfaces, deploy web application firewalls to filter suspicious HTTP requests, and apply strict access controls to restrict who can reach management endpoints. Additional defensive measures include monitoring network traffic for suspicious patterns that might indicate exploitation attempts, implementing intrusion detection systems with signatures for known attack patterns, and conducting thorough network assessments to identify any potential compromise. The vulnerability demonstrates the importance of maintaining up-to-date security patches and following the principle of least privilege for management interfaces, as the attack surface for such critical vulnerabilities can be exploited without requiring sophisticated attack techniques or significant resources.