NetScaler ADC and NetSCaler Gateway Security Bulletin for CVE-2023-24487, CVE-2023-24488

NetScaler ADC and NetSCaler Gateway Security Bulletin for CVE-2023-24487, CVE-2023-24488

Citrix published on May, 9th a new Security Bulletin for NetScaler ADC and Netscaler Gateway. The severity is rated as medium. AXACOM is recommending to upgrade the NetScaler ADCs and Gateways in the next few days according to the Citrix CTX477714.

Please monitor as well the Citrix CTX article under the following link:

https://support.citrix.com/article/CTX477714/citrix-adc-and-citrix-gateway-security-bulletin-for-cve202324487-cve202324488

Vulnerabilities have been discovered in Citrix ADC and Citrix Gateway listed below, that, if exploited, could result in the following security issues: 

Impacted Products, Versions and Components

The following supported versions of Citrix ADC and Citrix Gateway are affected by this vulnerability: 

  • Citrix ADC and Citrix Gateway 13.1 before 13.1-45.61
  • Citrix ADC and Citrix Gateway 13.0 before 13.0-90.11
  • Citrix ADC and Citrix Gateway 12.1 before 12.1-65.35
  • Citrix ADC 12.1-FIPS before 12.1-55.296
  • Citrix ADC 12.1-NDcPP before 12.1-55.296

This bulletin only applies to customer-managed Citrix ADC and Citrix Gateway. Customers using Citrix-managed cloud services or Citrix-managed Adaptive Authentication do not need to take any action. 

CVE IDDescriptionPre-requisitesCWECVSS
CVE-2023-24488Cross site scriptingAppliance must be configured as a Gateway (SSL VPN, ICA Proxy, CVPN, RDP Proxy) OR AAA virtual serverCWE-796.1
CVE-2023-24487Arbitrary file readAccess to NSIP or SNIP with management interface accessCWE-2536.3

What Customers Should Do

Affected customers of Citrix ADC and Citrix Gateway are recommended to install the relevant updated versions of Citrix ADC or Citrix Gateway as soon as possible: 

  • Citrix ADC and Citrix Gateway 13.1-45.61 and later releases
  • Citrix ADC and Citrix Gateway 13.0-90.11 and later releases of 13.0  
  • Citrix ADC and Citrix Gateway 12.1-65.35 and later releases of 12.1  
  • Citrix ADC 12.1-FIPS 12.1-55.296 and later releases of 12.1-FIPS  
  • Citrix ADC 13.1-FIPS 13.1-37.150 and later releases of 13.1-FIPS  
  • Citrix ADC 12.1-NDcPP 12.1-55.296 and later releases of 12.1-NDcPP 
NetScaler ADC and NetSCaler Gateway Security Bulletin for CVE-2023-24487, CVE-2023-24488

NetScaler Kerberos Authentication funktioniert nach dem Windows Update 2022-11 nicht mehr

Kunden, die auf ihrem NetScaler Kerberos verwenden, bekommen nach dem Microsoft November Update ein Problem. Kerberos funktioniert danach nicht mehr mit dem NetScaler und auch weitere Umsysteme sind davon betroffen. Sie erhalten bei einem Login Versuch via NetScaler folgenden Eintrag im System Eventlog des Domain Controllers:

While processing an AS request for target service <service>, the account <account name> did not have a suitable key for generating a Kerberos ticket (the missing key has an ID of 1). The requested etypes : 18 3. The accounts available etypes : 23 18 17. Changing or resetting the password of <account name> will generate a proper key.

Es handelt sich dabei um einen Bug im November Update von Microsoft, welcher bereits offiziell bestätigt ist, s. https://learn.microsoft.com/en-us/windows/release-health/status-windows-11-22h2#2953msgdesc

und https://borncity.com/win/2022/11/14/microsoft-confirms-kerberos-authentication-issues-after-nov-2022-updates/

Aktuell ist ein Workaround, aber noch kein Fix vorhanden, s. UPDATE 15.11.2022, 12:36

Kunden sollten das November Update auf Domain Controllern daher zurückhalten, oder den Workaround implementieren.

Sobald eine Lösung existiert, wird dieser Artikel erneut aktualisiert.

UPDATE 15.11.2022, 12:36:

Citrix hat hier einen KB Artikel zu dem Problem veröffentlicht und auch einen Workaround beschrieben:

https://support.citrix.com/article/CTX474888/daas-vdas-not-registering-with-cloud-connectors-after-applying-microsoft-update-kb5019966

Umgemünzt auf den NetScaler bedeutet dies, dass der KCD Account so modifiziert werden muss, wie in dem Screenshot gezeigt:

Anschliessend funktioniert KCD auch mit gepatchten Domain Controllern wieder.

Sollte das nicht genügen, kann mit folgendem Registry Key das Verhalten bei der Kerberos Signaturüberprüfung angepasst werden, s. https://support.microsoft.com/en-us/topic/kb5020805-how-to-manage-kerberos-protocol-changes-related-to-cve-2022-37967-997e9acc-67c5-48e1-8d0d-190269bf4efb#registry5020805:

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Kdc]

«KrbtgtFullPacSignature»=dword:00000000

ACHTUNG: Diese Anpassungen sind nur als Workaround zu verstehen und sollten wieder rückgängig gemacht werden, sobald Microsoft einen Fix für den Fehler bereitstellt!

UPDATE 18.11.2022

Microsoft hat ein OOB Update für Domain Controller veröffentlicht, welches das oben beschriebene Problem löst.

Der offizielle Artikel und die Download Links sind hier zu finden: https://learn.microsoft.com/en-us/windows/release-health/windows-message-center#2961

Nach der Installation des Updates auf allen Domain Controllern ist es möglich RC4 wieder vom KCD Account zu entfernen (Attribut: msDS-SupportedEncryptionTypes, Value: 24) und falls gesetzt, den Reg Key «KrbtgtFullPacSignature» wieder zu entfernen.

NetScaler ADC and NetSCaler Gateway Security Bulletin for CVE-2023-24487, CVE-2023-24488

Citrix Gateway and Citrix ADC Security Bulletin for CVE-2022-27510 CVE-2022-27513 and CVE-2022-27516

Description of Problem

Vulnerabilities have been discovered in Citrix Gateway and Citrix ADC, listed below. Note that only appliances that are operating as a Gateway (appliances using the SSL VPN functionality or deployed as an ICA proxy with authentication enabled) are affected by the first issue, which is rated as a Critical severity vulnerability. 

CVE-ID  Description  CWE  Affected Products Pre-conditions 
CVE-2022-27510 Unauthorized access to Gateway user capabilities CWE-288: Authentication Bypass Using an Alternate Path or Channel Citrix Gateway, Citrix ADC Appliance must be configured as a  VPN (Gateway) 
CVE-2022-27513 Remote desktop takeover via phishing CWE-345: Insufficient Verification of Data Authenticity Citrix Gateway, Citrix ADC Appliance must be configured as a  VPN (Gateway) and the RDP proxy functionality must be configured
CVE-2022-27516 User login brute force protection functionality bypass CWE-693: Protection Mechanism Failure Citrix Gateway, Citrix ADC Appliance must be configured as a  VPN (Gateway)          OR AAA virtual server  and the user lockout functionality “Max Login Attempts” must be configured 

The following supported versions of Citrix ADC and Citrix Gateway are affected by this vulnerability: 

  • Citrix ADC and Citrix Gateway 13.1 before 13.1-33.47 
  • Citrix ADC and Citrix Gateway 13.0 before 13.0-88.12 
  • Citrix ADC and Citrix Gateway 12.1 before 12.1.65.21
  • Citrix ADC 12.1-FIPS before 12.1-55.289 
  • Citrix ADC 12.1-NDcPP before 12.1-55.289 

This bulletin only applies to customer-managed Citrix ADC and Citrix Gateway appliances. Customers using Citrix-managed cloud services do not need to take any action.

Please monitor any changes on the Citrix article as well: https://support.citrix.com/article/CTX463706/citrix-gateway-and-citrix-adc-security-bulletin-for-cve202227510-cve202227513-and-cve202227516

NetScaler ADC and NetSCaler Gateway Security Bulletin for CVE-2023-24487, CVE-2023-24488

Citrix Gateway Plug-in for Windows Security Bulletin for CVE-2022-21827

Description of Problem

A vulnerability has been discovered in Citrix Gateway Plug-in for Windows (Citrix Secure Access for Windows). If exploited, this issue would allow an adversary, who has gained local access to a computer with Citrix Gateway Plug-in installed, to corrupt or delete files as SYSTEM. This issue has the following identifier: 

CVE-ID  Description  CWE  Pre-conditions 
CVE-2022-21827 Arbitrary corruption or deletion of files as SYSTEM CWE-284: Improper Access Control Local access to a machine that has the vulnerable plug-in installed 

The following supported versions of Citrix Gateway Plug-in for Windows (Citrix Secure Access for Windows) are affected by this vulnerability: 

  • Citrix Gateway Plug-in for Windows versions before 21.9.1.2 

What Customers Should Do

This issue has been addressed in the following versions of Citrix Gateway Plug-in for Windows (Citrix Secure Access for Windows):

  • Citrix Gateway Plug-in for Windows version 21.9.1.2 and later releases 

Download Link: https://www.citrix.com/downloads/citrix-gateway/plug-ins/citrix-secure-access-client-for-windows.html

The original Citrix article can be found here: https://support.citrix.com/article/CTX341455

Citrix Gateway – Users stuck at spinning circle after credentials – Chrome or chromium update to Version 100.0.4896.60

Citrix Gateway – Users stuck at spinning circle after credentials – Chrome or chromium update to Version 100.0.4896.60

Nach Update des Chrome oder chromium basierende Browser auf die Version 100.0.4896.60 bekommen User nach der Anmeldung am Citrix Gateway ein «spinning circle» und nicht die published Apps angezeigt. Das Problem tritt aufgrund einer Inkompatibilität mit den Citrix ADC Custom Themes auf.

Betroffen ist die Citrix ADC/Gateway Version 13.0 83.29

Systeme mit Citrix ADC/Gateway Version 13.1 12.50 und höher sind nicht betroffen. Ebenfalls nicht betroffen sind Firefox, Apple Safari Browser und ältere Chrome/Chromium Browser.

Citrix hat hierzu einen Support Artikel mit einem Workaround publiziert:
https://support.citrix.com/article/CTX399433