Microsoft Exchange ECP Probe (ProxyShell / ProxyLogon) for 2026-05-21

May 21, 2026 WebExploit

Last Updated: 12:00 UTC

The Exchange Control Panel (/ecp/) is the attack surface for ProxyLogon (CVE-2021-26855) and ProxyShell (CVE-2021-34473/34523/31207). Both exploit chains begin with ECP requests and achieve unauthenticated RCE leading to ASPX webshell deployment on the Exchange server.

CVE References

CVE-2021-26855 CVE-2021-34473

MITRE ATT&CK

Tactic: Initial Access (TA0001)
Technique: T1190 — Exploit Public-Facing Application

Observed URIs

Attackers by Country

United States of America: 2United Kingdom of Great Britain and Northern Ireland: 1Singapore: 1Netherlands: 1
United States of America240.0%
United Kingdom of Great Britain and Northern Ireland120.0%
Singapore120.0%
Netherlands120.0%

IP Address : ASN : City/Provider

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