CVE-2017-3126 in FortiManager
Summary
by MITRE
An Open Redirect vulnerability in Fortinet FortiAnalyzer 5.4.0 through 5.4.2 and FortiManager 5.4.0 through 5.4.2 allows attacker to execute unauthorized code or commands via the next parameter.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 10/03/2020
The CVE-2017-3126 vulnerability represents a critical open redirect flaw discovered in Fortinet's FortiAnalyzer and FortiManager security appliances. This vulnerability affects versions 5.4.0 through 5.4.2 of both products, creating a significant security risk that can be exploited by malicious actors to bypass authentication mechanisms and gain unauthorized access to sensitive systems. The vulnerability specifically resides in the handling of the next parameter within the web interface, which fails to properly validate or sanitize user input before redirecting users to external destinations.
The technical implementation of this vulnerability stems from insufficient input validation in the web application layer of Fortinet's security appliances. When users navigate through the administrative interface and encounter certain authentication prompts or redirects, the application processes a next parameter that should contain a valid internal URL but instead accepts arbitrary input. This parameter is typically used to redirect users back to their intended destination after successful authentication or other operations. However, due to inadequate sanitization, attackers can manipulate this parameter to point to malicious external domains, enabling them to craft phishing attacks or redirect victims to compromised websites. The vulnerability maps directly to CWE-601 Open Redirect vulnerability, which is classified under the CWE top 25 most dangerous software weaknesses and is categorized as a web application security flaw that can be exploited for social engineering attacks.
The operational impact of this vulnerability extends beyond simple redirection, as it can serve as a stepping stone for more sophisticated attacks within enterprise environments. Attackers can leverage this flaw to create convincing phishing campaigns that appear legitimate, as the redirect originates from trusted Fortinet appliances. This capability significantly increases the success rate of social engineering attacks against organizational personnel who may not recognize the malicious redirection. The vulnerability can be particularly dangerous in environments where FortiAnalyzer and FortiManager are used for critical security monitoring and management functions, as successful exploitation could lead to unauthorized access to security logs, configuration data, and potentially allow attackers to manipulate security policies. Additionally, the vulnerability can be combined with other attack vectors such as credential stuffing or session hijacking to achieve persistent access to the affected systems.
Mitigation strategies for CVE-2017-3126 should focus on immediate patching and configuration hardening measures. Fortinet released security updates that address this vulnerability by implementing proper input validation and sanitization for the next parameter. Organizations should prioritize applying the latest firmware updates from Fortinet, specifically targeting versions that include the patched implementation of the web application redirect functionality. Network administrators should also implement additional monitoring controls to detect unusual redirect patterns or attempts to manipulate the next parameter in real-time. The ATT&CK framework categorizes this vulnerability under T1566 - Phishing, specifically targeting the use of web application flaws to enable social engineering attacks. Security teams should enhance their incident response procedures to include monitoring for suspicious redirect behavior and implement network segmentation to limit the potential impact of successful exploitation. Furthermore, regular security assessments should be conducted to identify similar input validation flaws in other web applications and ensure proper security controls are in place to prevent similar vulnerabilities from being introduced in future deployments.