Windows tightens RDP file use to block phishing-prone connections

Microsoft’s April 2026 updates for Windows 10 and Windows 11 add protections to curb phishing by malicious Remote Desktop (.rdp) files: first-open triggers educate users, and subsequent attempts show a security dialog listing the file’s publisher status, remote address, and local resource redirects with all options off by default. If unsigned, a caution label appears; if signed, the publisher is shown but verification is still encouraged. These protections apply only to opening RDP files, not to connections via the Windows Remote Desktop client, and can be temporarily disabled via a registry setting by admins. Microsoft urges keeping the safeguards enabled, noting that attackers have used rogue RDP files in campaigns (e.g., APT29) to steal data, credentials, or even clipboard contents and smart-card authentication.