Suspicious Telerik UI RadAsyncUpload Request Indicating CVE-2019-18935 Exploitation (via webserver)

PremiumReviewedSigma · High · v1
Category
webserver
Author
HuntRule
Published
2026-09-23
Updated
2026-09-23

ATT&CK techniques

Initial Access
  1. Recon

  2. Resource Dev

  3. Execution

  4. Persistence

  5. Priv Esc

  6. Defense Evasion

  7. Cred Access

  8. Discovery

  9. Lateral Movement

  10. Collection

  11. C2

  12. Exfiltration

  13. Impact

What it detects

This rule detects requests to the Telerik Web UI WebResource handler with the type rau parameter that drives the RadAsyncUpload component targeted by CVE-2019-18935. Threat actors send crafted requests to this endpoint to deserialize a malicious payload and drop a DLL on the server. Traffic to this specific handler and parameter is a strong exploitation signal for vulnerable Telerik deployments.

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Suspicious Telerik UI RadAsyncUpload Request Indicating CVE-2019-18935 Exploitation (via webserver)
Pivot detection · T1190 · 9 related

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.