CVE-2020-36845 in Security Awareness Training
Summary
by MITRE • 04/21/2025
The KnowBe4 Security Awareness Training application before 2020-01-10 contains a redirect function that does not validate the destination URL before redirecting. The response has a SCRIPT element that sets window.location.href to an arbitrary https URL.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 04/21/2025
The vulnerability identified as CVE-2020-36845 affects the KnowBe4 Security Awareness Training application, representing a critical security flaw that emerged prior to the release date of January 10, 2020. This issue manifests within the application's redirect functionality, where the system fails to properly validate destination URLs before executing redirects. The vulnerability specifically involves a script element within the application's response that directly manipulates window.location.href to an arbitrary https URL, creating a dangerous pathway for malicious actors to exploit.
The technical implementation of this vulnerability stems from improper input validation within the redirect mechanism of the KnowBe4 platform. When the application processes redirect requests, it does not sufficiently sanitize or validate the target URL parameters, allowing attackers to inject malicious URLs that will be executed within the user's browser context. This flaw operates at the application layer and directly affects the browser's navigation behavior through JavaScript manipulation, making it particularly dangerous as it can be leveraged to redirect users to phishing sites, malicious domains, or exploit other vulnerabilities on the target system. The vulnerability is classified under CWE-601 as an Open Redirect vulnerability, which occurs when an application redirects users to external sites without proper validation, and aligns with ATT&CK technique T1566.001 which covers the use of phishing emails to gain initial access.
The operational impact of this vulnerability extends beyond simple redirection attacks, as it creates opportunities for sophisticated social engineering campaigns and phishing attacks that can bypass traditional security controls. An attacker who successfully exploits this vulnerability can redirect authenticated users to malicious sites that appear legitimate, potentially stealing credentials, deploying malware, or conducting further reconnaissance. The fact that the vulnerability operates through a script element that sets window.location.href indicates that it affects the client-side behavior of the application, meaning that successful exploitation requires only a single malicious redirect parameter to compromise the user's browsing session. This makes the vulnerability particularly dangerous in enterprise environments where users may have elevated privileges or access to sensitive systems through the KnowBe4 platform.
Organizations utilizing the KnowBe4 Security Awareness Training application should immediately implement mitigations to address this vulnerability, including updating to the patched version released after January 10, 2020. The recommended approach involves implementing strict URL validation mechanisms that verify redirect destinations against a whitelist of approved domains or implementing proper URL sanitization before any redirect operations are executed. Additionally, security teams should monitor network traffic for suspicious redirect patterns and implement web application firewalls that can detect and block malicious redirect attempts. The vulnerability highlights the importance of input validation in web applications and demonstrates how seemingly simple functionality can create significant security risks when proper validation controls are absent. Organizations should also conduct thorough security assessments of their web applications to identify similar validation flaws that could potentially be exploited in the same manner, as the principles underlying this vulnerability are commonly found in many web applications and represent a fundamental security weakness that requires comprehensive remediation across all application components.