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CVE-2022-39369 Detail

Description

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 that starts enforcing service URL discovery validation, because there is unfortunately no 100% safe default config to use in PHP. Starting this version, it is required to pass in an additional service base URL argument when constructing the client class. For more information, please refer to the upgrading doc. This vulnerability only impacts the CAS client that the phpCAS library protects against. The problematic service URL discovery behavior in phpCAS < 1.6.0 will only be disabled, and thus you are not impacted from it, if the phpCAS configuration has the following setup: 1. `phpCAS::setUrl()` is called (a reminder that you have to pass in the full URL of the current page, rather than your service base URL), and 2. `phpCAS::setCallbackURL()` is called, only when the proxy mode is enabled. 3. If your PHP's HTTP header input `X-Forwarded-Host`, `X-Forwarded-Server`, `Host`, `X-Forwarded-Proto`, `X-Forwarded-Protocol` is sanitized before reaching PHP (by a reverse proxy, for example), you will not be impacted by this vulnerability either. If your CAS server service registry is configured to only allow known and trusted service URLs the severity of the vulnerability is reduced substantially in its severity since an attacker must be in control of another authorized service. Otherwise, you should upgrade the library to get the safe service discovery behavior.


Severity



CVSS 3.x Severity and Metrics:

NIST CVSS score matches with CNA score
CNA:  GitHub, Inc.
Base Score:  8.0 HIGH
Vector:  CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H


NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.

Note: The NVD and the CNA have provided the same score. When this occurs only the CNA information is displayed, but the Acceptance Level icon for the CNA is given a checkmark to signify NVD concurrence.

References to Advisories, Solutions, and Tools

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Hyperlink Resource
https://github.com/apereo/phpCAS/security/advisories/GHSA-8q72-6qq8-xv64 Mitigation  Third Party Advisory 
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/2XL7SMW6ESSP2Y6HHRYWW2MMCZSI4LBZ/ Mailing List  Third Party Advisory 
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/RUA2JM6YT3ZXSZLBJVRA32AXYM3GJMO3/ Mailing List  Third Party Advisory 
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/VJZGTWJ5ZXUUT47EHARNOUUNTH6SYDSE/ Mailing List  Third Party Advisory 

Weakness Enumeration

CWE-ID CWE Name Source
NVD-CWE-Other Other cwe source acceptance level NIST  
CWE-1287 Improper Validation of Specified Type of Input Contributor acceptance level GitHub, Inc.  
CWE-99 Improper Control of Resource Identifiers ('Resource Injection') Contributor acceptance level GitHub, Inc.  

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Change History

3 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2022-39369
NVD Published Date:
11/01/2022
NVD Last Modified:
01/11/2023
Source:
GitHub, Inc.