NetScaler ADC and NetScaler Gateway Security Bulletin for CVE-2023-6548 and CVE-2023-6549 – Denial of Service

NetScaler ADC and NetScaler Gateway Security Bulletin for CVE-2023-6548 and CVE-2023-6549 – Denial of Service

Description of Problem

Two vulnerabilities have been discovered in NetScaler ADC (formerly Citrix ADC) and NetScaler Gateway (formerly Citrix Gateway).

Affected Versions: 

The following supported versions of NetScaler ADC and NetScaler Gateway are affected by the vulnerabilities: 

  • NetScaler ADC and NetScaler Gateway 14.1 before 14.1-12.35
  • NetScaler ADC and NetScaler Gateway 13.1 before 13.1-51.15
  • NetScaler ADC and NetScaler Gateway 13.0 before 13.0-92.21
  • NetScaler ADC 13.1-FIPS before 13.1-37.176
  • NetScaler ADC 12.1-FIPS before 12.1-55.302
  • NetScaler ADC 12.1-NDcPP before 12.1-55.302

Note: NetScaler ADC and NetScaler Gateway version 12.1 is now End Of Life (EOL) and is vulnerable.

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

Summary: 

NetScaler ADC and NetScaler Gateway contain the vulnerabilities described below. 

CVE IDDescriptionPre-requisitesCWECVSS
CVE-2023-6548Authenticated (low privileged) remote code execution on Management InterfaceAccess to NSIP, CLIP or SNIP with management interface accessCWE-945.5
CVE-2023-6549Denial of ServiceAppliance must be configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) OR AAA virtual serverCWE-1198.2

Mitigating Factors

CVE- 2023- 6548 only impacts the management interface. Cloud Software Group strongly recommends that network traffic to the appliance’s management interface is separated, either physically or logically, from normal network traffic. In addition, we recommend that you do not expose the management interface to the internet, as explained in the secure deployment guide. Removing such exposure to the internet greatly reduces the risk of exploitation of this issue. See NetScaler secure deployment guide ( https://docs.citrix.com/en-us/citrix-adc/citrix-adc-secure-deployment/secure-deployment-guide.html) for more information.


What Customers Should Do

Exploits of these CVEs on unmitigated appliances have been observed. Cloud Software Group strongly urges affected customers of NetScaler ADC and NetScaler Gateway to install the relevant updated versions as soon as possible. 

  • NetScaler ADC and NetScaler Gateway 14.1-12.35 and later releases
  • NetScaler ADC and NetScaler Gateway  13.1-51.15 and later releases of 13.1
  • NetScaler ADC and NetScaler Gateway 13.0-92.21 and later releases of 13.0  
  • NetScaler ADC 13.1-FIPS 13.1-37.176 and later releases of 13.1-FIPS  
  • NetScaler ADC 12.1-FIPS 12.1-55.302 and later releases of 12.1-FIPS  
  • NetScaler ADC 12.1-NDcPP 12.1-55.302 and later releases of 12.1-NDcPP 

Note: NetScaler ADC and NetScaler Gateway version 12.1 is now End Of Life (EOL). Customers are recommended to upgrade their appliances to one supported version that addresses the vulnerabilities. 

NetScaler ADC and NetScaler Gateway Security Bulletin for CVE-2023-6548 and CVE-2023-6549 – Denial of Service

Citrix ADC NetScaler and Citrix Gateway Security Bulletin for CVE-2023-3519, CVE-2023-3466, CVE-2023-3467

Es wird empfohlen das Update sobald wie möglich einzuspielen!

Description of Problem

Multiple vulnerabilities have been discovered in NetScaler ADC (formerly Citrix ADC) and NetScaler Gateway (formerly Citrix Gateway).

The following supported versions of NetScaler ADC and NetScaler Gateway are affected by the vulnerabilities: 

  • NetScaler ADC and NetScaler Gateway 13.1 before 13.1-49.13 
  • NetScaler ADC and NetScaler Gateway 13.0 before 13.0-91.13 
  • NetScaler ADC 13.1-FIPS before 13.1-37.159
  • NetScaler ADC 12.1-FIPS before 12.1-65.36 
  • NetScaler ADC 12.1-NDcPP before 12.65.36 

Note: NetScaler ADC and NetScaler Gateway version 12.1 is now End Of Life (EOL) and is vulnerable.

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

CVE IDAffected ProductsDescriptionPre-requisitesCWECVSS
CVE-2023-3466Citrix ADCReflected Cross-Site Scripting (XSS)Requires victim to access an attacker-controlled link in the browser while being on a network with connectivity to the NSIPCWE-208.3
CVE-2023-3467Citrix ADCPrivilege Escalation to root administrator (nsroot)Authenticated access to NSIP or SNIP with management interface accessCWE-2698
CVE-2023-3519Citrix ADCUnauthenticated remote code executionAppliance must be configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) OR AAA virtual serverCWE-949.8

What Customers Should Do

Exploits of CVE-2023-3519 on unmitigated appliances have been observed. Cloud Software Group strongly urges affected customers of NetScaler ADC and NetScaler Gateway to install the relevant updated versions as soon as possible. 

  • NetScaler ADC and NetScaler Gateway 13.1-49.13  and later releases
  • NetScaler ADC and NetScaler Gateway 13.0-91.13  and later releases of 13.0  
  • NetScaler ADC 13.1-FIPS 13.1-37.159 and later releases of 13.1-FIPS  
  • NetScaler ADC 12.1-FIPS 12.1-65.36 and later releases of 12.1-FIPS  
  • NetScaler ADC 12.1-NDcPP 12.1-65.36 and later releases of 12.1-NDcPP 

Note: NetScaler ADC and NetScaler Gateway version 12.1 is now End Of Life (EOL). Customers are recommended to upgrade their appliances to one of the supported versions that address the vulnerabilities. 

NetScaler ADC and NetScaler Gateway Security Bulletin for CVE-2023-6548 and CVE-2023-6549 – Denial of Service

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-2023-6548 and CVE-2023-6549 – Denial of Service

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-2023-6548 and CVE-2023-6549 – Denial of Service

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