How Windows UCPD Grew from a 29 KB Registry Filter into a 196 KB Policy Engine

TL;DR

• I collected 38 UCPD.sys binaries representing 24 versions
• UCPD first shipped in August 2023, seven months before its public discovery
• It grew from a 29 KB browser-association filter into a 196 KB registry and process policy engine
• Later versions added ACL, rename, injection, UI Automation, backtrace, and dynamic-rule defenses
• Versions 4.4–4.7 added cross-device resume, gaming, FeatureV3, and an expanded deny list

Going backward

My recent article examined how the Dynamic Rules (DR) work in the UCPD driver, and earlier research by Christoph Kolbicz, Gunnar Haslinger, and me captured individual stages of its development. The remaining piece was to track how the driver evolved over time.