CVE-2020-4399 in Verify Gateway
Summary
by MITRE
IBM Verify Gateway (IVG) 1.0.0 and 1.0.1 could allow an authenticated user to send malformed requests to cause a denial of service against the server. IBM X-Force ID: 179476.
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Analysis
by VulDB Data Team • 11/05/2020
IBM Verify Gateway version 1.0.0 and 1.0.1 contains a vulnerability that allows authenticated users to exploit a denial of service condition through malformed request handling. This weakness stems from insufficient input validation mechanisms within the application's request processing pipeline, where the system fails to properly sanitize or reject malformed data structures that could trigger unexpected behavior in the underlying processing logic. The vulnerability specifically affects the server-side request handling components that manage authentication and authorization workflows, creating a potential attack vector where a malicious authenticated user could craft specially formatted requests designed to overwhelm or destabilize the service.
The technical flaw manifests when the system processes requests containing malformed parameters or unexpected data patterns that are not properly validated before being processed by the core business logic. This type of vulnerability aligns with CWE-400, which categorizes unchecked input validation as a primary contributor to denial of service conditions. The processing failure occurs at the application layer where the system attempts to parse and interpret malformed request data, leading to resource exhaustion or application instability that can result in complete service unavailability. The vulnerability demonstrates characteristics of CWE-20, indicating improper input validation that allows malicious data to bypass security controls and potentially cause system disruption.
From an operational perspective, this vulnerability presents a significant risk to organizations relying on IBM Verify Gateway for authentication services, as it can be exploited by users who already possess valid credentials to disrupt critical infrastructure. The impact extends beyond simple service interruption to potentially compromise the integrity of the authentication system itself, as the denial of service condition could be used as a stepping stone for more sophisticated attacks. Attackers could leverage this weakness to target specific service endpoints or create cascading failures that affect downstream systems dependent on the gateway's authentication services. The vulnerability is particularly concerning because it requires only authenticated access to exploit, meaning that insider threats or compromised accounts could be weaponized to cause service disruption.
Mitigation strategies should focus on implementing comprehensive input validation mechanisms that can identify and reject malformed requests before they reach the core processing logic. Organizations should deploy robust request filtering rules that can detect anomalous parameter patterns and enforce strict data type validation for all incoming requests. The implementation of rate limiting and connection throttling mechanisms can help prevent exploitation attempts from exhausting system resources. Additionally, regular security updates and patches should be applied to ensure that the system maintains current protections against known vulnerabilities. The remediation approach should align with ATT&CK technique T1499 which addresses denial of service attacks, and should include monitoring for unusual request patterns that could indicate exploitation attempts. System administrators should also consider implementing intrusion detection systems that can identify and alert on malformed request patterns consistent with this vulnerability.