Widespread Exploitation of a Vulnerability in Telerik UI for ASP.NET

Widespread Exploitation of a Vulnerability in Telerik UI for ASP.NET

An update to the Telerik UI for ASP.NET cybersecurity advisory was issued today, May 12, 2020. There have been recent reports of the widespread exploitation of this vulnerability.

What It Is:
A vulnerability in Telerik UI for ASP.NET could allow for arbitrary code execution. ASP.NET is an open-source server-side web application framework designed for web development to produce dynamic web pages.

Successful exploitation of this vulnerability could allow for remote code execution within the context of a privileged process. Depending on the privileges associated with this application, an attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. If this application has been configured to have fewer user rights on the system, exploitation of this vulnerability could have less impact than if it was configured with administrative rights.

Read the original Telerik Support Bulletin.

Threat Intelligence:
Cybersecurity Advisory Update 5/12/2020: MS-ISAC is aware of recent widespread exploitation of this vulnerability.

Systems Affected:
• Progress Telerik UI for ASP.NET AJAX versions prior to 2020.1.114

Risk:
Government:
• Large and medium government entities: High
• Small government entities: Medium
Businesses:
• Large and medium business entities: High
• Small business entities: Medium
Home users: Low

What It Means:
If you and/or your business utilize the Telerik versions mentioned above, you will need to apply the appropriate patches provided by Telerik to vulnerable systems immediately following proper testing.

Technical Summary:
A vulnerability in Telerik UI for ASP.NET could allow for arbitrary code execution within the context of a privileged process. This issue exists due to a deserialization issue with .NET JavaScriptSerializer through RadAsyncUpload, which can lead to the execution of arbitrary code on the server in the context of the w3wp.exe process.

What To Do:
We recommend the following actions be taken:

• Apply appropriate patches provided by Telerik to vulnerable systems immediately after appropriate testing.
• Telerik UI may also be used by other web applications. Ensure other web applications that utilize Telerik UI have also been patched after appropriate testing.
• Run all software as a non-privileged user (one without administrative rights) to diminish the effects of a successful attack.
• Apply the Principle of Least Privilege to all systems and services.

Negative Consequences of Lost or Stolen Data:
The loss or theft of proprietary data can have severe impacts, particularly if the compromise becomes public and sensitive information is exposed. Possible impacts include:

• Temporary or permanent loss of sensitive or proprietary information.
• Disruption to regular operations.
• Financial losses incurred to restore systems and files.
• Potential harm to an organization’s reputation.

Should your agency or business need assistance with issues arising from vulnerabilities in Telerik UI for ASP.NET including updates and/or patches, Dox can help. Please contact Dox if there is anything we can do to assist in securing your agency, business, or organization.

Thank you for your time and stay safe online.