CVE-2018-19646 in SecureSphere
Summary
by MITRE
The Python CGI scripts in PWS in Imperva SecureSphere 13.0.10, 13.1.10, and 13.2.10 allow remote attackers to execute arbitrary OS commands because command-line arguments are mishandled.
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Analysis
by VulDB Data Team • 04/16/2020
The vulnerability identified as CVE-2018-19646 affects Imperva SecureSphere PWS versions 13.0.10, 13.1.10, and 13.2.10 where Python CGI scripts are improperly handling command-line arguments leading to remote code execution. This flaw resides in the web application firewall's handling of user-supplied input through CGI interfaces that are part of the SecureSphere platform's web proxy services. The vulnerability represents a critical security weakness that allows unauthenticated remote attackers to execute arbitrary operating system commands on the affected system with the privileges of the web server process. The issue stems from improper input validation and sanitization of command-line parameters that are passed to system-level functions, creating a path for command injection attacks. This vulnerability directly maps to CWE-78 which describes improper neutralization of special elements used in OS commands, and CWE-88 which addresses insufficient sanitization of command line arguments. The ATT&CK framework categorizes this as a command injection technique under the T1059.001 sub-technique for Windows command shell and T1059.002 for Unix shell, demonstrating how attackers can leverage this weakness to gain unauthorized access to underlying operating systems.
The technical implementation of this vulnerability occurs when user input is directly concatenated or passed to system commands without proper sanitization or escaping mechanisms. In the context of PWS within SecureSphere, when CGI scripts process incoming requests, they may accept user-supplied parameters that are then used to construct system calls or execute shell commands. The mishandling of these command-line arguments creates an environment where attackers can inject malicious commands that will be executed by the operating system with the privileges of the web server process. This typically manifests when the application fails to properly escape or quote command-line parameters, allowing attackers to append additional commands or manipulate the execution flow. The vulnerability is particularly dangerous because it enables attackers to execute arbitrary commands on the target system, potentially leading to full system compromise, data exfiltration, or lateral movement within the network.
The operational impact of CVE-2018-19646 is severe and far-reaching for organizations using affected SecureSphere versions. Remote attackers can leverage this vulnerability to execute commands with the privileges of the web server process, which may be running with elevated permissions depending on the system configuration. This capability allows adversaries to establish persistent access, escalate privileges, install backdoors, or perform reconnaissance activities on the underlying operating system. The vulnerability affects the integrity and confidentiality of the entire SecureSphere appliance, potentially compromising the security controls that the platform is designed to provide. Organizations may experience complete system compromise, data breaches, or unauthorized access to sensitive network resources. The impact extends beyond the immediate system to potentially affect the broader network infrastructure, as attackers could use the compromised system as a foothold for further attacks. The vulnerability also undermines the trust model of the web application firewall, as it allows attackers to bypass the very security controls that SecureSphere is intended to provide.
Mitigation strategies for CVE-2018-19646 should focus on immediate remediation through vendor-provided patches and updates. Organizations must upgrade to versions of Imperva SecureSphere that contain the necessary fixes for the command-line argument handling issue. Additionally, network segmentation and access controls should be implemented to limit exposure of vulnerable components to untrusted networks. Input validation and sanitization should be enhanced at all levels where user-supplied data is processed, particularly in CGI script execution contexts. The implementation of proper command escaping and quoting mechanisms can prevent the injection of malicious commands into system calls. Security monitoring and intrusion detection systems should be configured to detect suspicious command execution patterns and anomalous network activity. Regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in other components of the SecureSphere platform or related systems. Organizations should also implement principle of least privilege for web server processes to minimize the potential impact of successful exploitation. The vulnerability highlights the importance of secure coding practices and proper input validation, emphasizing the need for defensive programming techniques that prevent command injection attacks through proper parameter handling and system call construction.