CVE-2022-22690 in Umbraco
Summary
by MITRE • 01/18/2022
Within the Umbraco CMS, a configuration element named "UmbracoApplicationUrl" (or just "ApplicationUrl") is used whenever application code needs to build a URL pointing back to the site. For example, when a user resets their password and the application builds a password reset URL or when the administrator invites users to the site. For Umbraco versions less than 9.2.0, if the Application URL is not specifically configured, the attacker can manipulate this value and store it persistently affecting all users for components where the "UmbracoApplicationUrl" is used. For example, the attacker is able to change the URL users receive when resetting their password so that it points to the attackers server, when the user follows this link the reset token can be intercepted by the attacker resulting in account takeover.
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Analysis
by VulDB Data Team • 01/20/2022
The vulnerability identified as CVE-2022-22690 represents a critical configuration flaw within the Umbraco Content Management System that affects versions prior to 9.2.0. This issue stems from the improper handling of the "UmbracoApplicationUrl" configuration parameter, which serves as the foundation for generating internal application URLs throughout the CMS. The vulnerability specifically manifests when administrators fail to explicitly configure this parameter, creating an exploitable condition where malicious actors can manipulate the application's URL generation logic. The flaw resides in the application's default behavior of automatically determining the base URL when no explicit configuration is provided, which creates a persistent manipulation vector that affects all users of the system.
The technical implementation of this vulnerability allows attackers to inject malicious URLs into the UmbracoApplicationUrl configuration setting through various attack vectors. When the system operates without explicit configuration, it defaults to using the HTTP_HOST header or other server-provided information to construct URLs, which can be manipulated by attackers. This configuration manipulation becomes persistent because the system stores the modified URL value in its configuration system, affecting all subsequent URL generation operations. The vulnerability specifically impacts authentication workflows such as password reset functionality and user invitation processes where the system automatically constructs URLs pointing back to the application. According to CWE-807, this represents a "Reliance on Untrusted Inputs in a Security Decision" vulnerability, where the application's security decisions are based on potentially manipulated input data.
The operational impact of CVE-2022-22690 extends beyond simple URL manipulation, creating a significant account takeover risk for affected systems. When attackers successfully manipulate the UmbracoApplicationUrl setting, they can redirect users to malicious servers during critical authentication processes, particularly password reset operations. This creates an ideal environment for phishing attacks and credential theft, as users who follow the manipulated reset links unknowingly submit their credentials to attacker-controlled infrastructure. The attack chain typically involves initial access through a vulnerability in the configuration management system, followed by persistent manipulation of the application URL, and finally user interaction with the maliciously crafted reset links. This vulnerability aligns with ATT&CK technique T1566.001 for credential harvesting through phishing and T1071.004 for application layer protocol usage in command and control communications.
Mitigation strategies for CVE-2022-22690 require immediate implementation of explicit configuration management for the UmbracoApplicationUrl parameter. Organizations should ensure that all Umbraco installations have the ApplicationUrl explicitly defined in their configuration files, preventing the system from relying on potentially manipulated server headers. The recommended approach includes setting the parameter to a fixed, trusted URL value that reflects the actual application deployment. Additionally, administrators should implement proper input validation and sanitization for all configuration parameters, particularly those used in URL construction. Security monitoring should include detection of unauthorized configuration changes through file integrity monitoring solutions, as this vulnerability specifically targets the persistence of malicious configuration values. The most effective long-term solution involves upgrading to Umbraco version 9.2.0 or later, which includes proper validation and sanitization of the application URL configuration. Organizations should also implement network-level controls to prevent unauthorized access to configuration management interfaces and establish regular security audits of application configuration settings to detect potential manipulation attempts.