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Blue Mockingbird and what it means for Sitefinity

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TitleBlue Mockingbird and what it means for Sitefinity
URL NameBlue-Mockingbird-and-what-it-means-for-Sitefinity
Article Number000193769
EnvironmentProduct: Sitefinity
Version: 7.x, 8.x, 9.x, 10.x, 11.x, 12.x
OS: All supported OS versions
Database: All supported Microsoft SQL Server versions
Question/Problem Description

The Blue Mockingbird is a malware attack, which is compromising the security of many web applications, including Microsoft Information Services, SharePoint and Citrix. The attack is also targeting old Telerik UI vulnerabilities that have already been patched. 

The attack often uses the known vulnerabilities CVE-2017-11317 and CVE-2019-18935  They are already fixed, when they were found, and Progress notified customers with instructions and mitigation steps. 

Sitefinity uses Telerik UI for ASP.NET AJAX components and Telerik.Web.UI dll is shipped as part of the Sitefinity solution. The following guidance should be followed, to make sure Sitefinity is not using an unpatched version of the Telerik.Web.UI dll. 

Steps to Reproduce
Clarifying Information
Error Message
Defect Number
Enhancement Number

For the highest security, we recommend an upgrade to the latest Progress Sitefinity CMS release.   


Actions required: 

---->  For versions 13.0 and up -  No action required 

Sitefinity 13.0.7300 is using Telerik.Web.UI version 2020.1.114 which is not vulnerable against arbitrary file upload. 

----> For versions 10.2 to until 12.2  

Those versions are using patched Telerik.Web.UI versions, but require the use of unique encryption keys in the web.config file:  





How to Apply encryption keys in the web.config file:

Sitefinity has provided a form to facilitate the insertion and generation of the needed keys in the web.config file: 

1. Download this web form: 

2. Put it on the root folder of your project. 

3. Navigate to 

4. Click on the button to allow for the keys to be automatically inserted 

5. Double-check that the web.config has the values inserted. They should look like this: 

<add key="Telerik.AsyncUpload.ConfigurationEncryptionKey" value="*******" /> 

<add key="Telerik.Upload.ConfigurationHashKey" value="*******" /> 

<add key="Telerik.Web.UI.DialogParametersEncryptionKey" value=****>

Note : For optimal security, we highly recommend upgrading to the latest available patch.


----> For versions 7.0 until 10.1 

-> Upgrade Sitefinity to the following versions and apply the keys in the web.config as follows*

       I. Upgrade Sitefinity, to the latest patch available to your version. 

Progress article 000193776  How to apply the latest available patch?

       II. Update the keys: 

1. Download this webform: 

2. Put it on the root folder of your project. 

3. Navigate to 

4. Click on the button to allow for the keys to be automatically inserted 

5. Double-check that the web.config has the values inserted. They should look like this: 

<add key="Telerik.AsyncUpload.ConfigurationEncryptionKey" value="*******" /> 

<add key="Telerik.Upload.ConfigurationHashKey" value="*******" /> 

<add key="Telerik.Web.UI.DialogParametersEncryptionKey" value=****>
* The form will not insert new keys if they are already added. 

Additional references: 

Progress Article  Security Advisory Resolving Security Vulnerability CVE-2014-2217 , CVE-2017-11317 , CVE-2017-11357 , CVE-2017-9248 in Sitefinity

Telerik.Com blog, Mockingbird vulnerability 


Last Modified Date11/20/2020 6:52 AM
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