--- title: Register Mapping: From Blind Scan to Process... description: A hands-on walkthrough of OT/ICS exploitation methodology using the GRFICSv3 virtualized chemical plant lab. Covers the full process of Modbus register... canonical: https://daily.dev/posts/register-mapping-from-blind-scan-to-process-understanding-in-grficsv3-7gkf1wgcp twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Register Mapping: From Blind Scan to Process Understanding in GRFICSv3 | daily.dev og:description: A hands-on walkthrough of OT/ICS exploitation methodology using the GRFICSv3 virtualized chemical plant lab. Covers the full process of Modbus register... og:url: https://daily.dev/posts/register-mapping-from-blind-scan-to-process-understanding-in-grficsv3-7gkf1wgcp og:image: https://api.daily.dev/og/posts/7Gkf1WGCP.png og:image:alt: Register Mapping: From Blind Scan to Process Understanding in GRFICSv3 og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Register Mapping: From Blind Scan to Process Understanding in GRFICSv3 **[InfoSec Write-ups](https://daily.dev/sources/infosecwriteups)** · 11 min read · 0 upvotes · 0 comments ## Summary A hands-on walkthrough of OT/ICS exploitation methodology using the GRFICSv3 virtualized chemical plant lab. Covers the full process of Modbus register enumeration: blind sweeping all function codes, behavioral classification through time-series polling, and correlating raw UINT16 register values with HMI engineering units using the Tennessee Eastman process scaling formula. Demonstrates why PLC output registers (%QW) cannot be held by external writes while internal memory registers (%MW) accept and retain writes. Shows a live setpoint manipulation attack on HR 1026 (pressure setpoint) that causes measurable reactor pressure drift — the same attack class as the Oldsmar water treatment incident. Emphasizes that the Modbus write itself is trivial; the real work is building a labeled register map without access to PLC source code or HMI project files. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [OT Reconnaissance with Wireshark and GrassMarlin](https://daily.dev/posts/ot-reconnaissance-with-wireshark-and-grassmarlin-409rg4nbe) · InfoSec Write-ups · 0 upvotes · 0 comments - [SolarDisruption Lab Writeup \(CyberDefenders\)](https://daily.dev/posts/solardisruption-lab-writeup-cyberdefenders--jyuqhjlfx) · InfoSec Write-ups · 0 upvotes · 0 comments - [Spaghettifying DRAM](https://daily.dev/posts/spaghettifying-dram-qaft61ryu) · Hacker News · 0 upvotes · 0 comments --- [View this post on daily.dev](https://daily.dev/posts/register-mapping-from-blind-scan-to-process-understanding-in-grficsv3-7gkf1wgcp) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Register Mapping: From Blind Scan to Process Understanding in GRFICSv3","url":"https://daily.dev/posts/register-mapping-from-blind-scan-to-process-understanding-in-grficsv3-7gkf1wgcp","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/register-mapping-from-blind-scan-to-process-understanding-in-grficsv3-7gkf1wgcp"},"datePublished":"2026-04-24T10:55:32.843Z","dateModified":"2026-04-24T10:56:04.530Z","description":"A hands-on walkthrough of OT/ICS exploitation methodology using the GRFICSv3 virtualized chemical plant lab. 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