CVE-2018-17317 in FruityWifi
Summary
by MITRE
FruityWifi (aka PatatasFritas/PatataWifi) 2.1 allows remote attackers to execute arbitrary commands via shell metacharacters in the io_mode, ap_mode, io_action, io_in_iface, io_in_set, io_in_ip, io_in_mask, io_in_gw, io_out_iface, io_out_set, io_out_mask, io_out_gw, iface, or domain parameter to /www/script/config_iface.php, or the newSSID, hostapd_secure, hostapd_wpa_passphrase, or supplicant_ssid parameter to /www/page_config.php.
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Analysis
by VulDB Data Team • 05/26/2020
FruityWifi version 2.1 contains a critical command injection vulnerability that affects multiple configuration endpoints within the web interface. This vulnerability stems from insufficient input validation and sanitization of user-supplied parameters across several php scripts including config_iface.php and page_config.php. The flaw allows remote attackers to execute arbitrary system commands by injecting shell metacharacters into parameters such as io_mode, ap_mode, io_action, and various interface configuration fields. The vulnerability exists because the application directly incorporates user input into shell commands without proper escaping or filtering mechanisms, creating a classic command injection attack vector that can be exploited from remote locations.
The technical implementation of this vulnerability follows CWE-77 principles for command injection, where attacker-controlled data flows directly into operating system command execution contexts. The affected parameters span across network configuration settings including interface parameters like io_in_iface, io_out_iface, and domain fields, as well as wireless configuration parameters such as newSSID, hostapd_secure, hostapd_wpa_passphrase, and supplicant_ssid. When these parameters are processed by the web application, they are concatenated into shell commands without proper sanitization, enabling attackers to chain shell metacharacters like semicolons, pipes, and backticks to execute additional commands beyond the intended functionality. This vulnerability operates at the application layer and can be exploited through standard http requests targeting the vulnerable php endpoints.
The operational impact of this vulnerability is severe and potentially catastrophic for systems running FruityWifi 2.1. Remote attackers can gain complete system control over affected devices, potentially leading to unauthorized network access, data exfiltration, or further lateral movement within compromised networks. The vulnerability affects the core network configuration functionality of the application, meaning that successful exploitation could allow attackers to modify network interfaces, change wireless access point settings, and potentially gain persistent access to the underlying operating system. This represents a critical compromise of the device's integrity and confidentiality, as attackers can execute any command that the web application process has privileges to run. The attack can be performed without authentication, making it particularly dangerous in environments where the application is exposed to untrusted networks.
Mitigation strategies for this vulnerability should focus on implementing proper input validation and sanitization across all user-controllable parameters. The application must escape or filter shell metacharacters from all inputs before they are used in command execution contexts. Implementing parameterized commands or using safe command execution libraries instead of direct shell invocation can prevent this class of vulnerability. Network segmentation and access controls should be implemented to limit exposure of the vulnerable web interface to trusted networks only. Additionally, the application should be updated to a version that addresses this vulnerability, as the maintainers have likely released patches to fix the input validation issues. Organizations should also consider implementing web application firewalls to detect and block malicious command injection attempts. The vulnerability aligns with ATT&CK technique T1059.001 for command and scripting interpreter, specifically targeting the use of shell commands for privilege escalation and system control. Regular security audits and input validation testing should be performed to identify similar vulnerabilities in other applications that may be vulnerable to command injection attacks.