CVE-2019-18935
Progress Telerik UI for ASP.NET AJAX contains a deserialization of untrusted data vulnerability through RadAsyncUpload which leads to code execution on the server in the context of the w3wp.exe process.
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.)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H- packetstormsecurity.com/files/155720/Telerik-UI-Remote-Code-Execution.htmlThird Party AdvisoryVDB Entry
- packetstormsecurity.com/files/159653/Telerik-UI-ASP.NET-AJAX-RadAsyncUpload-Deserialization.htmlExploitThird Party Advisory
- codewhitesec.blogspot.com/2019/02/telerik-revisited.htmlNot Applicable
- github.com/bao7uo/RAU_cryptoExploitThird Party Advisory
- github.com/noperator/CVE-2019-18935ExploitThird Party Advisory
- know.bishopfox.com/research/cve-2019-18935-remote-code-execution-in-telerik-uiExploitThird Party Advisory
- bleepingcomputer.com/news/security/us-federal-agency-hacked-using-old-telerik-bug-to-steal-data/Press/Media Coverage
- telerik.com/support/kb/aspnet-ajax/details/allows-javascriptserializer-deserializationPatchVendor Advisory
- telerik.com/support/whats-new/aspnet-ajax/release-history/ui-for-asp-net-ajax-r1-2020-%28version-2020-1-114%29Release Notes
- telerik.com/support/whats-new/release-historyRelease NotesVendor Advisory
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-18935US Government Resource
Actively exploited and used by ransomware crews. Patch immediately.
- Exploitation
- Confirmed in the wild (CISA KEV)
- Federal remediation deadline
- Overdue by 1637 days
- Ransomware
- Used in known ransomware campaigns
- CVSS
- 9.8 CRITICAL
- EPSS (30-day exploit probability)
- 99.7% · top 1% of all CVEs
- Weakness
- CWE-502
- Attack vector
- Network, remotely reachable
- Preconditions
- No privileges and no user interaction
- 1.Apply updates per vendor instructions.
- 2.Treat as emergency change: patch or isolate internet-facing instances first.
- 3.Review exposure: confirm which instances are reachable from the internet and restrict access until patched.
- 4.Hunt for compromise: review logs for the disclosure window, not just from the patch date.
- 5.Verify offline/immutable backups and segment the affected systems. This flaw is used for ransomware initial access.
Assessment is derived automatically from the live signals above; verify against your own asset inventory.