CVE-2017-6748 in Web Security Appliance
Summary
by MITRE
A vulnerability in the CLI parser of the Cisco Web Security Appliance (WSA) could allow an authenticated, local attacker to perform command injection and elevate privileges to root. The attacker must authenticate with valid operator-level or administrator-level credentials. Affected Products: virtual and hardware versions of Cisco Web Security Appliance (WSA). More Information: CSCvd88855. Known Affected Releases: 10.1.0-204. Known Fixed Releases: 10.5.1-270 10.1.1-234.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 01/06/2021
The vulnerability identified as CVE-2017-6748 represents a critical command injection flaw within the command line interface parser of Cisco Web Security Appliance versions 10.1.0-204 and earlier. This security weakness resides in the WSA's handling of user input through its CLI interface, where insufficient input validation and sanitization allows maliciously crafted commands to be executed with elevated privileges. The vulnerability specifically affects both virtual and hardware deployments of the Cisco WSA, making it a widespread concern across various deployment scenarios. The flaw stems from improper handling of command line arguments that enables an authenticated user to inject arbitrary commands into the system's execution pipeline, potentially leading to complete system compromise.
The technical nature of this vulnerability aligns with CWE-77 and CWE-20 categories, representing command injection and input validation issues respectively. The attack vector requires an authenticated user with operator-level or administrator-level credentials, which means the vulnerability cannot be exploited by unauthenticated users. However, this limitation does not diminish its severity since it allows privilege escalation from authenticated user level to root access. The flaw occurs during CLI parsing operations where user-supplied input is not properly sanitized before being processed by the system's command execution engine. This creates an environment where malicious input can bypass normal command validation and execute arbitrary system commands with the highest available privileges.
The operational impact of CVE-2017-6748 is severe and potentially devastating for organizations relying on Cisco WSA for web security protection. An attacker with valid credentials can leverage this vulnerability to gain complete control over the appliance, potentially allowing them to modify security policies, access sensitive network traffic, disable security features, or establish persistent access points within the network infrastructure. The vulnerability's exploitation could lead to complete compromise of the web security appliance, which serves as a critical control point for network traffic filtering and content inspection. This makes it particularly dangerous in environments where the WSA is used as a primary security control, as the attacker could undermine the entire security posture of the organization.
Organizations should immediately implement mitigations by upgrading to the fixed releases 10.5.1-270 or 10.1.1-234 as specified in the advisory. The upgrade process should be conducted with proper change management procedures to ensure minimal disruption to network security operations. Additional mitigations include implementing strict access controls to limit the number of users with operator or administrator privileges, enabling audit logging for CLI activities, and monitoring for suspicious command execution patterns. Network segmentation and the principle of least privilege should be enforced to limit potential damage if the vulnerability is exploited. Security teams should also consider implementing intrusion detection systems that can identify unusual command injection patterns and establish incident response procedures for potential exploitation attempts. The vulnerability's presence in both virtual and hardware versions underscores the importance of comprehensive patch management across all deployment types within an organization's infrastructure.