Progress Telerik UI - RCE (CVE-2019-18935)

CVE-2019-18935 is a critical vulnerability in Progress Telerik UI for ASP.NET AJAX that enables remote code execution through a flawed deserialization process in the RadAsyncUpload functionality, especially when encryption keys are exposed or known.

CrowdSec has been tracking this vulnerability and its exploits since 5th of April 2023.

Based on data from the CrowdSec network, nearly all observed exploitation of CVE-2019-18935 is fully opportunistic, with attackers indiscriminately scanning the entire internet. These attacks are automated and lack any form of target selection or reconnaissance. Telemetry from the CrowdSec network also shows that exploitation activity for CVE-2019-18935 remains steady week-over-week. Attack volumes are consistent with long-term trends, indicating sustained interest from threat actors. CVE-2019-18935 continues to be an active part of the threat landscape and will likely remain this way for the forseeable future.

Observed exploitation frequently involves requests crafted to abuse the RadAsyncUpload feature, leveraging the underlying deserialization flaw for code execution.