A vulnerability has been discovered in Citrix Gateway and Citrix ADC, listed below, that, if exploited, could allow an unauthenticated remote attacker to perform arbitrary code execution on the appliance.
CVE-ID
Description
CWE
Affected Products
Pre-conditions
CVE-2022-27518
Unauthenticated remote arbitrary code execution
CWE-664: Improper Control of a Resource Through its Lifetime
Citrix Gateway, Citrix ADC
Citrix ADC or Citrix Gateway must be configured as a SAML SP or a SAML IdP
The following supported versions of Citrix ADC and Citrix Gateway are affected by this vulnerability:
Citrix ADC and Citrix Gateway 13.0 before 13.0-58.32
Citrix ADC and Citrix Gateway 12.1 before 12.1-65.25
Citrix ADC 12.1-FIPS before 12.1-55.291
Citrix ADC 12.1-NDcPP before 12.1-55.291
Citrix ADC and Citrix Gateway version 13.1 is unaffected.
What Customers Should Do
Exploits of this issue on unmitigated appliances in the wild have been reported. Citrix strongly urges affected customers of Citrix ADC and Citrix Gateway to install the relevant updated versions of Citrix ADC or Citrix Gateway as soon as possible:
Citrix ADC and Citrix Gateway 13.0-58.32 and later releases
Citrix ADC and Citrix Gateway 12.1-65.25 and later releases of 12.1
Citrix ADC 12.1-FIPS 12.1-55.291 and later releases of 12.1-FIPS
Citrix ADC 12.1-NDcPP 12.1-55.291 and later releases of 12.1-NDcPP
Please note that Citrix ADC and Citrix Gateway versions prior to 12.1 are EOL and customers on those versions are recommended to upgrade to one of the supported versions.
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.
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.
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.
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.
Microsoft is investigating two reported zero-day vulnerabilities affecting Microsoft Exchange Server 2013, 2016, and 2019. The first vulnerability, identified as CVE-2022-41040, is a Server-Side Request Forgery (SSRF) vulnerability, while the second, identified as CVE-2022-41082, allows remote code execution (RCE) when PowerShell is accessible to the attacker.
What Customers Should Do
To protect your on-prem Exchange you can bind a responder policy on the Citrix ADC contentswitch handling all the Exchange related traffic:
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.
