Critical Citrix ADM (MAS) Security Bulletin for CVE-2022-27511 and CVE-2022-27512

Critical Citrix ADM (MAS) Security Bulletin for CVE-2022-27511 and CVE-2022-27512

Description of Problem

Vulnerabilities have been discovered in Citrix Application Delivery Management (Citrix ADM) that, if exploited, could result in the following security issues: 

  • Corruption of the system by a remote, unauthenticated user. The impact of this can include the reset of the administrator password at the next device reboot, allowing an attacker with ssh access to connect with the default administrator credentials after the device has rebooted. 
  • Temporary disruption of the ADM license service. The impact of this includes preventing new licenses from being issued or renewed by Citrix ADM. 
CVE-ID  Description  CWE  Pre-conditions 
CVE-2022-27511 Corruption of the system by a remote, unauthenticated user potentially leading to the reset of the administrator password CWE-284: Improper Access Control Access to ADM IP 
CVE-2022-27512 Temporary disruption of the ADM license service  CWE-664: Improper Control of a Resource Through its Lifetime Access to ADM IP 

Da der ADM Zugangsdaten & Zugriff auf die konfigurierten Instanzen hat, wird empfohlen die Sicherheitslücke rasch zu schliessen in dem die ADM Instanz auf eine der folgenden Versionen aktualisiert wird:

  • Citrix ADM 13.1-21.53 and later versions of 13.1 
  • Citrix ADM 13.0-85.19 and later versions of 13.0 

Als Mitigation kann versucht werden die ADM Management IP über eine Firewall zu sperren.

Normalerweise ist das ADM nur von intern zugänglich wodurch das Risiko einer Ausnutzung der Schwachstelle relativ klein ist. Ein Angreifer müsste bereits Zugang zum internen Netz haben. Wie die Schwachstelle ausgenutzt werden kann ist bisher unbekannt.

Für detaillierte Informationen und weitere Schritte, folgen Sie bitte den Informationen im Original Citrix Artikel. Gerne unterstützen wir Sie bei bedarf bei dem Update.


Critical Citrix ADM (MAS) Security Bulletin for CVE-2022-27511 and CVE-2022-27512

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

Critical Citrix ADM (MAS) Security Bulletin for CVE-2022-27511 and CVE-2022-27512

Spring4Shell (CVE-2022-22963, CVE-2022-22965)

A zero-day exploit affecting the Spring Framework versions (5.3.0 to 5.3.17, 5.2.0 to 5.2.19, and older versions was made public on March 30, 2022, allowing an unauthenticated attacker to execute arbitrary code on the target system.

Citrix recommends that customers hosting affected web applications follow Spring’s recommendations. In addition, Citrix Web App Firewall (WAF) customers should consider the following recommendations to improve the security of their applications from this vulnerability.

The Citrix research team has released updated Citrix WAF signatures designed to mitigate in part the CVE-2022-22963, CVE-2022-22965 vulnerability. If you are using any of these Spring Framework versions (5.3.0 to 5.3.17, 5.2.0 to 5.2.19, and older versions), Citrix strongly recommends that you download the signatures version 79 and apply to your Citrix WAF deployments as an additional layer of protection for your applications. Signatures are compatible with the following software versions of Citrix Application Delivery Controller (ADC) 11.1, 12.0, 12.1, 13.0 and 13.1. Please note, versions 11.1 and 12.0 are end of life.

Citrix ADC Produkte sind selber nicht von der Sicherheitslücke betroffen.

Für alle Kunden, welche WAF nicht im Einsatz haben, gibt es auch eine Empfehlung seitens Citrix, die Sicherheitslücke mittels Responder Policy zu minimieren:

Citrix ADC Standard and Advanced edition customers, as well as Premium edition customers who do not have WAF signatures enabled, can use responder policies for protection as shown below. Please bind the responder policy to the appropriate bind point (vserver or global).

add responder policy mitigate_cve_2022_22963_22965 q^(HTTP.REQ.FULL_HEADER. SET_TEXT_MODE(URLENCODED).DECODE_USING_TEXT_MODE.
CONTAINS("spring.cloud.function.routing-expression") || HTTP.REQ.BODY(8192).SET_TEXT_MODE(URLENCODED).DECODE_USING_TEXT_MODE.CONTAINS(".classLoader"))^ DROP

Citrix recommends that Citrix WAF customers use the latest signature version, enable signatures auto-update, and subscribe to receive signature alert notifications. Citrix will continue to monitor this dynamic situation and update as new mitigations become available.

If any of your application availability is inadvertently impacted due to false positives resulting from above mentioned mitigation policies, Citrix recommends the following modifications to the policy. Please note that any end point covered by the exception_list may expose those assets to the risks from CVE-2022-22963, CVE-2022-22965.

Mehr Informationen sind hier zu finden:

https://www.citrix.com/blogs/2022/04/01/guidance-for-reducing-spring4shell-security-vulnerability-risk-with-citrix-waf/
Release Notes der WAF Signaturen:
https://docs.citrix.com/en-us/citrix-adc/current-release/application-firewall/signature-alerts/signature-update-version-79.html

Bei Fragen zum Update und dem Einsatz der Citrix ADC WAF bzw. der Signaturen, wenden Sie sich an unseren Support.

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

EPA fails after Chrome/Edge version 98 update

Mit den neusten Version der vom Chrome (v98+), Edge (v98+). Brave (1.43+) funktioniert der EPA Scan nicht mehr. Betroffen sind Windows sowie MAC OS Betriebsysteme.

Citrix hat hierzu einen Workaround veröffentlicht und arbeitet an einer Lösung. Es wird empfohlen Firefox oder Safari Browser für die Zugriffe zu verwenden.

Mehr Informationen und die Workarounds sind im folgenden Citrix Artikel zu finden:

https://support.citrix.com/article/CTX339975

Update: 28.02.2022

Citrix has identified the issue and released a new EPA plugin for Windows and macOS

For Windows: https://www.citrix.com/en-in/downloads/citrix-gateway/plug-ins/citrix-gateway-windows-plug-in-clients.html

For macOS: https://www.citrix.com/downloads/citrix-gateway/earlier-versions/EPA-plug-in-v3238-for-macOS.html