Headline
Ubuntu Security Notice USN-6913-1
Ubuntu Security Notice 6913-1 - Filip Hejsek discovered that phpCAS was using HTTP headers to determine the service URL used to validate tickets. A remote attacker could possibly use this issue to gain access to a victim’s account on a vulnerable CASified service. This security update introduces an incompatible API change. After applying this update, third party applications need to be modified to pass in an additional service base URL argument when constructing the client class.
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Ubuntu Security Notice USN-6913-1
July 24, 2024
php-cas vulnerability
A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 22.04 LTS
- Ubuntu 20.04 LTS
Summary:
phpCAS was vulnerable to an authentication bypass.
Software Description:
- php-cas: Central Authentication Service client library in php
Details:
Filip Hejsek discovered that phpCAS was using HTTP headers to determine
the service URL used to validate tickets. A remote attacker could
possibly use this issue to gain access to a victim’s account on a
vulnerable CASified service.
This security update introduces an incompatible API change. After applying
this update, third party applications need to be modified to pass in an
additional service base URL argument when constructing the client class.
For more information please refer to the section
“Upgrading 1.5.0 -> 1.6.0” of the phpCAS upgrading document:
https://github.com/apereo/phpCAS/blob/master/docs/Upgrading
Update instructions:
The problem can be corrected by updating your system to the following
package versions:
Ubuntu 22.04 LTS
php-cas 1.3.8-1ubuntu0.22.04.1
Ubuntu 20.04 LTS
php-cas 1.3.8-1ubuntu0.20.04.1
In general, a standard system update will make all the necessary changes.
References:
https://ubuntu.com/security/notices/USN-6913-1
CVE-2022-39369
Package Information:
https://launchpad.net/ubuntu/+source/php-cas/1.3.8-1ubuntu0.22.04.1
https://launchpad.net/ubuntu/+source/php-cas/1.3.8-1ubuntu0.20.04.1
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Ubuntu Security Notice 6914-1 - Filip Hejsek discovered that the phpCAS library included in OCS Inventory was using HTTP headers to determine the service URL used to validate tickets. A remote attacker could possibly use this issue to gain access to a victim's account.
### Impact The phpCAS library uses HTTP headers to determine the service URL used to validate tickets. This allows an attacker to control the host header and use a valid ticket granted for any authorized service in the same SSO realm (CAS server) to authenticate to the service protected by phpCAS. Depending on the settings of the CAS server service registry in worst case this may be any other service URL (if the allowed URLs are configured to "^(https)://.*") or may be strictly limited to known and authorized services in the same SSO federation if proper URL service validation is applied. This vulnerability may allow an attacker to gain access to a victim's account on a vulnerable CASified service without victim's knowledge, when the victim visits attacker's website while being logged in to the same CAS server. ### Patch phpCAS 1.6.0 is a major version upgrade that starts enforcing service URL discovery validation, because there is unfortunately no 100% safe default config to use...
phpCAS is an authentication library that allows PHP applications to easily authenticate users via a Central Authentication Service (CAS) server. The phpCAS library uses HTTP headers to determine the service URL used to validate tickets. This allows an attacker to control the host header and use a valid ticket granted for any authorized service in the same SSO realm (CAS server) to authenticate to the service protected by phpCAS. Depending on the settings of the CAS server service registry in worst case this may be any other service URL (if the allowed URLs are configured to "^(https)://.*") or may be strictly limited to known and authorized services in the same SSO federation if proper URL service validation is applied. This vulnerability may allow an attacker to gain access to a victim's account on a vulnerable CASified service without victim's knowledge, when the victim visits attacker's website while being logged in to the same CAS server. phpCAS 1.6.0 is a major version upgrade tha...