CVE-2017-3129 in FortiWeb
Summary
by MITRE
A Cross-Site Scripting vulnerability in Fortinet FortiWeb versions 5.7.1 and below allows attacker to execute unauthorized code or commands via an improperly sanitized POST parameter in the FortiWeb Site Publisher feature.
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Analysis
by VulDB Data Team • 05/27/2017
The vulnerability identified as CVE-2017-3129 represents a critical cross-site scripting flaw within Fortinet FortiWeb web application firewalls, specifically affecting versions 5.7.1 and earlier. This security weakness resides within the FortiWeb Site Publisher feature, which is designed to facilitate web content management and application deployment. The vulnerability stems from inadequate input validation and sanitization processes that fail to properly handle malicious payloads submitted through POST requests. Attackers can exploit this flaw by crafting specially designed malicious input within POST parameters, bypassing the intended security controls that should protect against such attacks.
The technical implementation of this vulnerability aligns with CWE-79, which categorizes cross-site scripting as a code injection flaw occurring when untrusted data is directly included in web pages without proper sanitization or encoding. The flaw manifests when the FortiWeb appliance processes user-supplied data through the Site Publisher functionality, where the system fails to adequately sanitize or escape input before incorporating it into dynamic web content. This improper handling creates an environment where malicious scripts can be executed within the context of a victim's browser session, potentially compromising the integrity of web applications protected by the FortiWeb appliance.
The operational impact of this vulnerability extends beyond simple script execution, as it provides attackers with a potential foothold for more sophisticated attacks within the network infrastructure. An attacker who successfully exploits this vulnerability could execute unauthorized commands on the affected FortiWeb appliance, potentially leading to full compromise of the web application firewall's administrative functions. This could result in unauthorized access to protected web applications, data exfiltration, or the ability to modify web content through the compromised FortiWeb instance. The attack vector through POST parameters makes this particularly concerning as it can be executed through normal web application interactions without requiring special privileges or direct system access.
Organizations utilizing affected FortiWeb versions should implement immediate mitigations including upgrading to Fortinet FortiWeb version 5.7.2 or later, which contains the necessary patches to address this vulnerability. Additionally, network administrators should consider implementing additional security controls such as web application firewalls, input validation rules, and monitoring for suspicious POST request patterns. The vulnerability demonstrates the importance of proper input sanitization and the critical need for regular security updates in network infrastructure components. Security teams should also conduct thorough vulnerability assessments to identify any potential exploitation attempts and implement comprehensive monitoring strategies to detect anomalous behavior in web application traffic that may indicate attempted exploitation of this or similar vulnerabilities.