Citrix Application Delivery Controller, Citrix Gateway, and Citrix SD-WAN WANOP appliance Security Update

On Sep 17, Citrix released CTX281474 article with three vulnerabilities which are fixed by new firmware releases on all supported version tracks. The following vulnerabilities are addressed here: CVE-2020-8245: An html injection attack against SSL VPN portal, CVE-2020-8246: A Denial-of-Service attack originating from the management network CVE-2020-8247: A escalation of privileges on the management interface. 8246 & 8287 are attacks on the management interfaces which should NOT be directly reachable from unauthorized…

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Citrix VDA 2006 + 2009: Citrix ICA could not configure Thinwire and switch to the remote ICA display

After an experimental upgrade on some VDAs in a customer’s environment experiencing issues when connecting to our Windows 10 virtual desktops. Desktop Viewer starts up, stuck for some seconds and closes without any error or event. We just see this window: After some minutes you just see the connection on the VM is closed due to the VDA timeout. Internal connections through Storefront are working fine all the time. So…

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Citrix ADC 13.0-64-35 and Storefront “Cannot complete your request” (CVE-2020-8245, CVE-2020-8246 or CVE-2020-8247)

Starting with Citrix ADC feature release 13.0 build 64.35, some weak SSO types are dishonored globally. This affects Citrix XenDesktop Site and the Citrix Storefront authentication mechanism between Citrix Gateway and SF directly. These SSO types will be now disabled by default: Basic authentication Digest Access authentication NTLM without Negotiate NTLM2 Key or Negotiate Sign This means Single Sign-On (SSO) configuration in Citrix ADC and Citrix Gateway has to be…

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LDAP channel binding changes in 2020

Microsoft announced an update that is going to disable unsigned LDAP by default. What does this mean for administrators? Long story short, but you can no longer use bindings to domain controllers over port 389. After the installation of the update you have to use either LDAPS over port 636 or using StartTLS on port 389. Both scenarios still require to add a certificate on the domain controllers. Microsoft has…

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Citrix Synergy 2019 – my thoughts and my personal review

Right back from Citrix Synergy 2019 in Atlanta I was thinking about a personal conclusion of the great event and the days with a lot of insights into the strategy and Citrix‘ ideas for the future of work. First of all, I try to list the great announcements and product upgrades Citrix gave at the keynote. David Hanshall (CEO) and PJ Hough presented a very good overview and gave a…

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CTX232387 – Citrix Studio Error: You have read only access to the license server

Note In addition to this Citrix KNB article I found in some environments it is not enough to set the LimitRequestFieldSize like described, but you can set the value higher. See below the size I tested and validated (24k). A higher value 36k or 48k was not accepted and you will see errors in Citrix Studio for all users. Symptoms or Error When Licensing node is selected in Studio: Error…

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Netscaler – AD Group permission check on vserver level

In a Netscaler project I came to a requirement, to check if an user is member of an specific Active Directory group before the request is forwarded to the load balancing vServer. The customer has multiple lb vservers, which are protected by an simple AAA authentication server. The authentication domain was set to the top level domain, e.g. fabric.com.  The following subdomains are representing the other applications: sharepoint.fabric.com jira.fabric.com documentcenter.fabric.com …

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Microsoft Surface: CTX236170 HDX session stops responding when using two-finger scroll on a touchpad

Something I observed since a very long time on my Mircosoft Surface Book 2 is now confirmed by Citrix Support: Citrix HDX session may stop responding and hang when using the two-finger scroll on a touchpad. This was observed in certain machines running Windows 8 or 10 with receiver 4.10 or higher. There is currently no solution, but the workaround to press a system keys like Alt-tab or windows key…

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Risk-based Authentication with Netscaler n-Factor Feature and forwarding credentials to SAML

Scenario We came across a requirement while implementing Citrix Netscaler as a central authentication instance for web applications, which was described with several needs on the customer site. User are going to start a cloud web application for example from SAP or other cloud providers This application will create a SAML request and send it to a Netscaler AAA service to authenticate the users from an on-premise repository (LDAP) Netscaler…

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Insert your Password Policy notification in Netscaler Gateway 11.1

  I am often asked to customize the Netscaler logon pages with the company corporate design, logos and other stuff. Another very common requirement is, to have the opportunity to set a hint what is the compony’s LDAP password complexity policy, when the user have to change their passwords in a remote scenario. Netscaler does not offer any functionality to do this in the GUI. The second challenge is, Citrix…

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