CVE-2017-7736 in FortiWeb webUI Certificate View Page
Summary
by MITRE
A stored Cross-site Scripting (XSS) vulnerability in Fortinet FortiWeb webUI Certificate View page in 5.8.0, 5.7.1 and earlier, allows attackers to inject arbitrary web script or HTML via special crafted malicious certificate import.
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Analysis
by VulDB Data Team • 01/25/2021
The vulnerability identified as CVE-2017-7736 represents a critical stored cross-site scripting flaw within the Fortinet FortiWeb web application firewall's user interface. This security weakness exists specifically in the Certificate View page functionality of FortiWeb versions 5.8.0, 5.7.1, and earlier releases, making a significant portion of the FortiWeb product line susceptible to exploitation. The flaw arises from insufficient input validation and output sanitization mechanisms when processing certificate data within the web user interface, creating a persistent security risk that can be exploited by remote attackers without requiring authentication or elevated privileges.
The technical implementation of this vulnerability stems from the improper handling of certificate import operations within the FortiWeb management interface. When administrators or authorized users import certificates through the webUI, the system fails to adequately sanitize or encode the certificate data before storing and displaying it within the Certificate View page. This allows malicious actors to craft specially formatted certificate files containing embedded malicious script code that gets executed whenever the compromised certificate information is rendered in the browser interface. The stored nature of this vulnerability means that the malicious payload persists within the system's database and executes every time the affected page is accessed, regardless of whether the original attacker remains active.
The operational impact of CVE-2017-7736 extends beyond simple script execution, as it provides attackers with a persistent foothold within the FortiWeb management interface. This vulnerability can be leveraged to perform session hijacking, steal administrative credentials, redirect users to malicious domains, or even execute arbitrary commands within the context of the web application. The implications are particularly severe given that FortiWeb serves as a critical security appliance protecting web applications from various threats, making its compromise a significant risk to overall network security posture. Attackers can exploit this vulnerability to gain unauthorized access to the web application firewall's administrative functions, potentially leading to complete system compromise and unauthorized modification of security policies.
From a cybersecurity framework perspective, this vulnerability aligns with CWE-79, which describes Cross-site Scripting flaws in web applications, and maps to ATT&CK technique T1059.007 for script execution through web applications. The vulnerability also demonstrates characteristics of the ATT&CK tactic TA0006 (credential access) and TA0008 (lateral movement) as attackers can use the compromised interface to escalate privileges and move laterally within the network. Organizations using affected FortiWeb versions face significant risk of unauthorized access to their web application security controls, potentially allowing attackers to bypass the very protections that FortiWeb is designed to provide. The stored nature of the vulnerability means that even after the initial attack, the malicious code continues to execute, creating a persistent threat that can evade traditional security monitoring mechanisms.
Organizations should immediately implement mitigation strategies including applying the latest Fortinet security patches and firmware updates, implementing network segmentation to limit access to the FortiWeb management interface, and conducting comprehensive security assessments of their web application firewall configurations. Additionally, administrators should review certificate import procedures and implement strict validation controls for certificate data, while monitoring web application logs for suspicious activity related to certificate management operations. The vulnerability highlights the importance of input validation and output encoding practices in web application security, emphasizing the need for comprehensive security testing and regular vulnerability assessments to identify and remediate similar weaknesses in enterprise security infrastructure.