CVE-2018-20122 in Fastweb
Summary
by MITRE
The web interface on FASTGate Fastweb devices with firmware through 0.00.47_FW_200_Askey 2017-05-17 (software through 1.0.1b) exposed a CGI binary that is vulnerable to a command injection vulnerability that can be exploited to achieve remote code execution with root privileges. No authentication is required in order to trigger the vulnerability.
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Analysis
by VulDB Data Team • 07/11/2023
The vulnerability identified as CVE-2018-20122 represents a critical command injection flaw within the web interface of FASTGate Fastweb devices running specific firmware versions. This vulnerability exists in the CGI binary component that handles web requests, creating an avenue for attackers to execute arbitrary commands on the affected devices. The flaw is particularly concerning because it operates without requiring any authentication credentials, making it accessible to anyone who can reach the device's web interface. The affected firmware versions include 0.00.47_FW_200_Askey 2017-05-17 and software versions up to 1.0.1b, indicating this issue was present in a significant portion of the device's deployment history. The vulnerability stems from improper input validation within the web application's command execution mechanism, where user-supplied data is directly passed to system commands without adequate sanitization or escaping.
The technical exploitation of this vulnerability allows attackers to achieve remote code execution with root privileges, representing a severe privilege escalation issue. The absence of authentication requirements means that an attacker can exploit this flaw from any network location without needing to establish credentials first. This command injection vulnerability typically occurs when the application fails to properly validate or sanitize user input before using it in system calls, which aligns with CWE-77 and CWE-89 classifications from the CWE database. The exploitation process likely involves crafting malicious input parameters that get passed directly to shell commands, enabling attackers to execute arbitrary system commands with the highest level of system privileges. This type of vulnerability can be classified under the ATT&CK framework as T1059.001 (Command and Scripting Interpreter: PowerShell) or similar techniques depending on the specific implementation details, though the broader category of T1068 (Exploitation for Privilege Escalation) applies directly to this scenario.
The operational impact of this vulnerability extends beyond simple remote code execution to encompass complete system compromise and potential network infiltration. Devices affected by this vulnerability can be used as launch points for further attacks within a network, potentially allowing attackers to establish persistent access, exfiltrate sensitive data, or use the compromised device as a pivot point for attacking other systems. The root privilege execution capability means that attackers can modify system files, install backdoors, disable security features, or completely take control of the device's functionality. Organizations relying on these devices for network infrastructure may face significant security risks, as the vulnerability affects devices that are often deployed in critical network segments where they serve as gateways or access points for network traffic. The lack of authentication requirements makes this vulnerability particularly dangerous in environments where devices are accessible from untrusted networks or when devices are improperly configured with default settings.
Mitigation strategies for this vulnerability require immediate firmware updates from the manufacturer to address the command injection flaw in the web interface components. Organizations should implement network segmentation to limit access to these devices, ensuring that only authorized personnel can reach the web interface. Network monitoring should be enhanced to detect suspicious traffic patterns that may indicate exploitation attempts, particularly focusing on unusual command execution patterns or unexpected network connections originating from these devices. Access controls should be strengthened through the implementation of strong authentication mechanisms, even though the vulnerability exists in the web interface itself. Security teams should conduct comprehensive network assessments to identify all affected devices and implement temporary network access restrictions until proper firmware updates can be deployed. The vulnerability also underscores the importance of regular security audits and vulnerability assessments for network infrastructure devices, as well as the necessity of maintaining up-to-date security patches across all deployed systems. Additionally, network administrators should consider implementing intrusion detection systems that can identify and alert on exploitation attempts targeting known vulnerabilities in network infrastructure devices.