CVE-2019-18935
CRITICALCVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Lifecycle Timeline
5Description
Progress Telerik UI for ASP.NET AJAX through 2019.3.1023 contains a .NET deserialization vulnerability in the RadAsyncUpload function. This is exploitable when the encryption keys are known due to the presence of CVE-2017-11317 or CVE-2017-11357, or other means. Exploitation can result in remote code execution. (As of 2020.1.114, a default setting prevents the exploit. In 2019.3.1023, but not earlier versions, a non-default setting can prevent exploitation.)
Analysis
Progress Telerik UI for ASP.NET AJAX contains a .NET deserialization vulnerability in RadAsyncUpload that allows unauthenticated remote code execution when encryption keys are known, exploited by APT groups and ransomware operators.
Technical Context
The CWE-502 deserialization flaw exists in the RadAsyncUpload handler's processing of serialized .NET objects. The handler uses encryption to protect upload parameters, but if the key is known (via prior CVEs or default configurations), an attacker can craft encrypted payloads containing malicious serialized objects for code execution.
Affected Products
['Progress Telerik UI for ASP.NET AJAX through 2019.3.1023']
Remediation
Update Telerik UI to 2020.1.114+. Change default encryption keys to unique, random values. Implement .NET serialization binders to restrict deserializable types. Monitor for web shells in Telerik upload directories.
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External POC / Exploit Code
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