Researchers at High-Tech Bridge have uncovered multiple vulnerabilities in the Web interface of pfSense that can be exploited to perform cross-site scripting (XSS) and cross-site request forgery (CSRF) attacks.
PfSense is an open source firewall/router software distribution based on the FreeBSD operating system.
“Successful exploitation of the vulnerabilities may allow an attacker to delete arbitrary files on the system with root privileges, steal administrator’s cookies and gain complete control over the web application and even the entire system, as pfSense is running with root privileges and allows OS command execution via its web interface,” according to the High-Tech Bridge advisory.
The issues have been patched, and users are advised to update to the latest version.
All totaled the update fixes five cross-site scripting issues and one cross-site request forgery issue. In one XSS issue, the input passed via the “zone” HTTP GET parameter to “/status_captiveportal.php” is not properly sanitized before being returned to the user.
A remote attacker can trick a logged-in administrator into opening a specially-crafted link and executing arbitrary HTML and script code in browser in the context of the vulnerable website, High-Tech Bridge noted in the advisory. In another case, it is input passed via the “if” and “dragtable” HTTP GET parameters to “/firewall_rules.php” that is not being properly sanitized before it is returned to the user.
In the case of all the XSS vulnerabilities, a remote attacker can trick a logged-in administrator to open a specially-crafted link and execute arbitrary HTML and script code in browser in the context of the vulnerable website, High-Tech Bridge noted in the advisory.
The lone CSRF vulnerability exists due to insufficient validation of the HTTP request origin in “/system_firmware_restorefullbackup.php”. According to High-Tech Bridge, a remote attacker can trick a log-in administrator to visit a malicious page with CSRF exploit and delete arbitrary files on the target system with root privileges.
“These vulnerabilities are a good example of global ‘webization’ – almost any software today, including the most complex one, has a web interface for simplicity and compatibility reasons,” said Ilia Kolochenko, CEO at security firm High-Tech Bridge. “And the web interface is the weakest point usually – people tend to seriously underestimate the risks of vulnerable web applications. Moreover, many companies rely on purely automated solutions to test their web application security, while classic web vulnerability scanning is not capable of detecting all of the vulnerabilities. Obviously, hackers will not spend much time or effort on compromising complex front-end software, if they can get-in by a simple web hack. Attacks targeting web applications will definitely grow in the future as hackers prefer quick and easy ways to access your ‘secure’ information.”