CVE-2018-10842 in KeyCloak
Summary
by MITRE
It was found that an authenticated user could manipulate user session information to trigger an infinite loop in keycloak. A malicious user could use this flaw to conduct a denial of service attack against the server.
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Analysis
by VulDB Data Team • 03/15/2020
The vulnerability identified as CVE-2018-10842 represents a critical security flaw within the Keycloak identity and access management platform that affects authenticated users with the ability to manipulate session data. This issue manifests as an infinite loop condition that can be triggered through deliberate manipulation of user session information, creating a pathway for malicious actors to execute denial of service attacks against Keycloak servers. The vulnerability specifically targets the session management mechanisms within Keycloak's authentication framework, where improper validation of session data allows for recursive processing that consumes excessive system resources and ultimately leads to service disruption.
The technical implementation of this vulnerability stems from inadequate input validation and session handling logic within Keycloak's authentication subsystem. When an authenticated user manipulates specific session parameters, the system enters a recursive processing loop where session validation routines repeatedly call themselves without proper termination conditions. This flaw operates at the application layer and requires authentication credentials to exploit, making it particularly dangerous as it can be leveraged by users with legitimate access to the system. The infinite loop consumes CPU cycles and memory resources, effectively preventing the server from processing legitimate authentication requests and maintaining normal service operations.
From an operational impact perspective, this vulnerability creates significant risks for organizations relying on Keycloak for identity management and access control. The denial of service condition can render authentication services unavailable to legitimate users, potentially blocking access to critical applications and systems that depend on Keycloak for authentication. Attackers can exploit this vulnerability with relatively simple session manipulation techniques, requiring minimal technical expertise while causing substantial disruption. The impact extends beyond immediate service unavailability as it can affect business continuity, user productivity, and may require emergency system maintenance to restore normal operations.
Organizations should implement immediate mitigations including updating to patched versions of Keycloak where this vulnerability has been addressed through proper session validation and loop detection mechanisms. The fix typically involves implementing bounds checking on session data processing, adding timeout mechanisms to prevent recursive operations, and strengthening input validation routines. Security teams should also consider implementing monitoring solutions to detect anomalous session processing patterns that could indicate exploitation attempts. Additionally, network segmentation and access controls can limit the scope of potential exploitation by restricting access to Keycloak services. This vulnerability aligns with CWE-835, which addresses infinite loops in software systems, and maps to ATT&CK technique T1499.004 for denial of service attacks, emphasizing the need for comprehensive defensive measures including proper session management, resource limiting, and continuous monitoring of authentication service behavior.