CVE-2018-9920 in Smartforms
Summary
by MITRE
Server side request forgery exists in the runtime application in K2 smartforms 4.6.11 via a modified hostname in an https://*/Identity/STS/Forms/Scripts URL.
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Analysis
by VulDB Data Team • 02/08/2020
The vulnerability identified as CVE-2018-9920 represents a critical server-side request forgery flaw within the K2 smartforms runtime application version 4.6.11. This security weakness stems from inadequate input validation and sanitization mechanisms that fail to properly restrict or validate hostname parameters within the authentication and identity management components of the system. The vulnerability specifically manifests in the https://*/Identity/STS/Forms/Scripts URL structure where an attacker can manipulate the hostname portion to redirect requests to arbitrary destinations. This flaw allows malicious actors to potentially access internal network resources, bypass authentication mechanisms, or perform unauthorized data access operations. The issue falls under the Common Weakness Enumeration category CWE-918, which specifically addresses server-side request forgery vulnerabilities where applications fail to properly validate and sanitize external input used in request construction. The attack vector leverages the trust relationship between the application and its internal services, potentially enabling attackers to exploit the application's ability to make requests to internal systems that would normally be restricted from external access. This vulnerability aligns with ATT&CK technique T1071.004, which covers application layer protocol manipulation, specifically targeting web protocols and application interfaces.
The technical exploitation of this vulnerability occurs when the K2 smartforms application processes a request containing a modified hostname parameter within the identity and access management flow. The application fails to validate that the hostname parameter originates from a trusted source or falls within expected domain boundaries, allowing an attacker to inject malicious hostnames that can redirect the application's internal requests. This flaw essentially enables an attacker to manipulate the application's behavior by forcing it to make requests to unintended destinations, potentially including internal servers, databases, or other sensitive infrastructure components. The impact extends beyond simple data leakage as the vulnerability can be leveraged to perform lateral movement within networks, access restricted resources, or even escalate privileges within the application's authentication framework. The specific URL pattern https://*/Identity/STS/Forms/Scripts provides an attack surface where the asterisk wildcard character can be manipulated to redirect the application's authentication requests to attacker-controlled endpoints, effectively bypassing normal security controls that would typically prevent such unauthorized access attempts.
The operational impact of CVE-2018-9920 is significant for organizations utilizing K2 smartforms 4.6.11, as it creates a persistent security risk that can be exploited by attackers with minimal privileges. Organizations may experience unauthorized access to internal systems, potential data breaches, and compromised authentication mechanisms that could affect the integrity and confidentiality of sensitive business processes. The vulnerability's exploitation can lead to unauthorized access to enterprise resources, including databases, file servers, and other internal services that the application may attempt to reach during normal authentication flows. This risk is particularly concerning in environments where the K2 smartforms application has elevated privileges or access to sensitive data repositories, as the compromise of this component can provide attackers with a foothold for further attacks within the network infrastructure. The vulnerability also poses challenges for incident response and forensic analysis, as the malicious requests may appear legitimate to network monitoring systems, making detection more difficult. Security teams face the additional burden of implementing temporary workarounds while awaiting official patches, potentially impacting business continuity and operational efficiency. The flaw's presence in a widely used business process automation platform means that organizations may have multiple points of exposure across their infrastructure where this vulnerability could be exploited.
Mitigation strategies for CVE-2018-9920 should prioritize immediate implementation of input validation controls and hostname restriction mechanisms within the K2 smartforms application configuration. Organizations should implement strict validation of all hostname parameters, particularly those used in authentication and identity management flows, to ensure that only trusted and expected domains are permitted. Network segmentation and firewall rules should be configured to restrict outbound connections from the K2 smartforms application to prevent unauthorized access to internal resources. The implementation of web application firewalls and security monitoring solutions can help detect and block suspicious hostname manipulation attempts. Organizations should also consider implementing additional authentication controls and access restrictions for the specific URL paths affected by this vulnerability, including limiting the scope of the application's ability to make external requests. Regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in other components of the application stack. The most effective long-term solution involves upgrading to patched versions of K2 smartforms 4.6.11, as the vendor has addressed this vulnerability in subsequent releases through enhanced input validation and improved hostname sanitization mechanisms. Security teams should also establish monitoring procedures to detect anomalous patterns in application behavior that may indicate exploitation attempts, ensuring comprehensive protection against both current and future variants of this class of vulnerability.