--- title: Analysis of Backdoored XZ Utils Build Process with... description: A detailed technical analysis of the XZ Utils supply chain attack (CVE-2024-3094) using StepSecurity Harden-Runner. The post walks through how the attacker... canonical: https://daily.dev/posts/analysis-of-backdoored-xz-utils-build-process-with-harden-runner-pnclgkhop twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Analysis of Backdoored XZ Utils Build Process with Harden-Runner | daily.dev og:description: A detailed technical analysis of the XZ Utils supply chain attack (CVE-2024-3094) using StepSecurity Harden-Runner. The post walks through how the attacker... og:url: https://daily.dev/posts/analysis-of-backdoored-xz-utils-build-process-with-harden-runner-pnclgkhop og:image: https://api.daily.dev/og/posts/pNClgkHop.png og:image:alt: Analysis of Backdoored XZ Utils Build Process with Harden-Runner 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. # Analysis of Backdoored XZ Utils Build Process with Harden-Runner **[StepSecurity](https://daily.dev/sources/stepsecurity)** · 7 min read · 0 upvotes · 0 comments ## Summary A detailed technical analysis of the XZ Utils supply chain attack (CVE-2024-3094) using StepSecurity Harden-Runner. The post walks through how the attacker modified the build-to-host.m4 file and embedded malicious compressed test files to inject a backdoor during the build process. Using Harden-Runner's real-time file write monitoring and process tree inspection on GitHub Actions, the analysis shows exactly how suspicious sed commands altered the Makefile, how an object file was created by decompressing a test file instead of compiling source code, and how a source file was modified in memory and piped to a compiler to backdoor the final xz binary. The post advocates integrating Harden-Runner into CI/CD pipelines to detect such tampering. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Could the XZ backdoor have been detected with better Git and Debian packaging practices?](https://daily.dev/posts/could-the-xz-backdoor-have-been-detected-with-better-git-and-debian-packaging-practices--rg1zju4bp) · Hacker News · 1 upvotes · 0 comments --- Tags: [#security](https://daily.dev/tags/security), [#cicd](https://daily.dev/tags/cicd), [#github-actions](https://daily.dev/tags/github-actions) [View this post on daily.dev](https://daily.dev/posts/analysis-of-backdoored-xz-utils-build-process-with-harden-runner-pnclgkhop) ```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":"Analysis of Backdoored XZ Utils Build Process with Harden-Runner","url":"https://daily.dev/posts/analysis-of-backdoored-xz-utils-build-process-with-harden-runner-pnclgkhop","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/analysis-of-backdoored-xz-utils-build-process-with-harden-runner-pnclgkhop"},"datePublished":"2026-03-31T12:25:30.387Z","dateModified":"2026-03-31T12:27:57.799Z","description":"A detailed technical analysis of the XZ Utils supply chain attack (CVE-2024-3094) using StepSecurity Harden-Runner. 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