Keycloak UI DoS via Offline Session Memory Exhaustion
CVE-2023-6563 Published on December 14, 2023

Keycloak: offline session token dos
An unconstrained memory consumption vulnerability was discovered in Keycloak. It can be triggered in environments which have millions of offline tokens (> 500,000 users with each having at least 2 saved sessions). If an attacker creates two or more user sessions and then open the "consents" tab of the admin User Interface, the UI attempts to load a huge number of offline client sessions leading to excessive memory and CPU consumption which could potentially crash the entire system.

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Vulnerability Analysis

CVE-2023-6563 can be exploited with network access, and requires small amount of user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.

Attack Vector:
NETWORK
Attack Complexity:
LOW
Privileges Required:
LOW
User Interaction:
NONE
Scope:
CHANGED
Confidentiality Impact:
NONE
Integrity Impact:
NONE
Availability Impact:
HIGH

Timeline

Reported to Red Hat.

Made public. 8 days later.

Weakness Type

Allocation of Resources Without Limits or Throttling

The software allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor.


Products Associated with CVE-2023-6563

You can be notified by email with stack.watch whenever vulnerabilities like CVE-2023-6563 are published in these products:

Red Hat Keycloak
 
Red Hat Single Sign On
 
Red Hat Single Sign On
 
Red Hat Rhosemc
 
Red Hat Build Keycloak
 

Affected Versions

Red Hat Single Sign-On 7.6 for RHEL 7: Red Hat Single Sign-On 7.6 for RHEL 8: Red Hat Single Sign-On 7.6 for RHEL 9: Red Hat RHEL-8 based Middleware Containers: Red Hat RHEL-8 based Middleware Containers: Red Hat Single Sign-On 7.6.6: Red Hat Build of Keycloak:

Exploit Probability

EPSS
0.30%
Percentile
53.26%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.