CVE-2020-4590 in WebSphere Application Server Liberty
Summary
by MITRE
IBM WebSphere Application Server Liberty 17.0.0.3 through 20.0.0.9 running oauth-2.0 or openidConnectServer-1.0 server features is vulnerable to a denial of service attack conducted by an authenticated client. IBM X-Force ID: 184650.
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Analysis
by VulDB Data Team • 09/22/2020
The vulnerability identified as CVE-2020-4590 affects IBM WebSphere Application Server Liberty versions 17.0.0.3 through 20.0.0.9 when the oauth-2.0 or openidConnectServer-1.0 server features are enabled. This represents a significant security concern as it allows authenticated attackers to execute denial of service attacks against the affected system. The flaw specifically targets the OpenID Connect server implementation within the Liberty profile, which is commonly used for identity management and single sign-on solutions in enterprise environments. The vulnerability stems from inadequate input validation and resource handling within the authentication processing pipeline, creating an exploitable condition that can be leveraged by malicious users who have already established authentication credentials within the system.
The technical implementation of this vulnerability involves a flaw in how the server processes certain OAuth 2.0 and OpenID Connect protocol requests. When an authenticated client sends specially crafted requests through the affected server features, the system fails to properly validate the incoming parameters and subsequently enters an infinite loop or consumes excessive system resources. This behavior is classified as a resource exhaustion vulnerability that can be triggered through legitimate authentication sessions, making it particularly dangerous as it can be exploited by insiders or compromised accounts. The vulnerability operates at the application layer and specifically targets the authentication and authorization processing components that handle OAuth 2.0 token exchanges and OpenID Connect authentication flows, which are fundamental to modern identity management systems.
The operational impact of CVE-2020-4590 extends beyond simple service disruption to potentially compromise the entire identity management infrastructure within organizations using affected IBM WebSphere Liberty profiles. Attackers can cause sustained denial of service conditions that may last for extended periods, effectively blocking legitimate users from accessing authenticated services while the system remains in a resource-consuming state. This vulnerability can be particularly damaging in production environments where continuous availability is critical, as it can lead to business disruptions, loss of productivity, and potential financial impacts. The attack vector requires only authenticated access, which means that even users with limited privileges can potentially cause significant system degradation, making this vulnerability particularly concerning for environments with shared or multi-tenant architectures.
Organizations should implement immediate mitigations including applying the relevant IBM security patches and updates that address the resource handling issues within the oauth-2.0 and openidConnectServer-1.0 features. Network segmentation and access controls should be strengthened to limit the scope of potential exploitation, while monitoring systems should be enhanced to detect unusual patterns in authentication request processing. The vulnerability aligns with CWE-400, which catalogs weaknesses related to resource exhaustion, and can be mapped to ATT&CK technique T1499.004 for denial of service attacks. Additionally, organizations should consider implementing rate limiting and request validation mechanisms to prevent exploitation, while maintaining detailed logging of authentication activities to detect potential abuse. The remediation process should include thorough testing of patched environments to ensure that legitimate functionality remains intact while the vulnerability is addressed.