--- title: File Upload Security in PHP and Laravel — The File That... description: File uploads are one of the most dangerous attack vectors in PHP applications. Attackers can achieve Remote Code Execution by uploading PHP scripts disguised... canonical: https://daily.dev/posts/file-upload-security-in-php-and-laravel-the-file-that-isn-t-what-it-claims-to-be-wcuzhbldv twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: File Upload Security in PHP and Laravel — The File That Isn’t What It Claims to Be | daily.dev og:description: File uploads are one of the most dangerous attack vectors in PHP applications. Attackers can achieve Remote Code Execution by uploading PHP scripts disguised... og:url: https://daily.dev/posts/file-upload-security-in-php-and-laravel-the-file-that-isn-t-what-it-claims-to-be-wcuzhbldv og:image: https://api.daily.dev/og/posts/wCuzhBLdV.png og:image:alt: File Upload Security in PHP and Laravel — The File That Isn’t What It Claims to Be 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. # File Upload Security in PHP and Laravel — The File That Isn’t What It Claims to Be **[Medium](https://daily.dev/sources/medium_js)** · 11 min read · 1 upvotes · 0 comments ## Summary File uploads are one of the most dangerous attack vectors in PHP applications. Attackers can achieve Remote Code Execution by uploading PHP scripts disguised as images. Five common bypass techniques are covered: variant PHP extensions, MIME type spoofing, double extensions, PHP code embedded in images, and path traversal via crafted filenames. The defense requires seven layers: server-side MIME detection with finfo, extension whitelisting, random filename generation, storing files outside the web root, disabling PHP execution in upload directories, image validation with getimagesize(), and file size limits. Complete code examples are provided for both plain PHP and Laravel, including what Laravel's built-in validation handles and what it doesn't (renaming, web root storage, execution prevention). A practical checklist summarizes all required steps for both environments. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### How do I prevent uploaded files from being executed as PHP scripts on my server? Store uploaded files outside the public web root so they cannot be reached via a URL, then serve them through a controller that reads and outputs the file content with the correct headers. As a second layer, configure the web server to deny PHP execution in any upload directory using an Nginx location block or an Apache .htaccess rule disabling the PHP engine. _daily.dev surfaces practical hardening patterns like this for developers securing PHP upload endpoints._ ### Why is checking $_FILES['type'] not safe for validating uploaded file types in PHP? The type field in the $_FILES array is a browser-supplied value that an attacker fully controls, so they can set it to image/jpeg while uploading a PHP shell script and pass the check. The reliable alternative is PHP's finfo extension, which reads the actual file bytes to determine the real MIME type rather than trusting the client. _Developers hardening file upload logic can find server-side validation patterns like this on daily.dev._ ### Does Laravel's image and mimes validation rule fully protect against malicious file uploads? No, Laravel's image rule uses getimagesize() and the mimes rule inspects actual file content rather than the browser header, so both resist basic spoofing, but Laravel does not rename uploaded files, does not store them outside the web root by default, does not disable PHP execution in the storage directory, and does not verify the extension matches the detected MIME type - all of which must be added manually. _Laravel developers weighing built-in validation against manual hardening steps can track guidance like this on daily.dev._ --- Tags: [#security](https://daily.dev/tags/security), [#php](https://daily.dev/tags/php), [#laravel](https://daily.dev/tags/laravel) [View this post on daily.dev](https://daily.dev/posts/file-upload-security-in-php-and-laravel-the-file-that-isn-t-what-it-claims-to-be-wcuzhbldv) ```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":"File Upload Security in PHP and Laravel — The File That Isn’t What It Claims to Be","url":"https://daily.dev/posts/file-upload-security-in-php-and-laravel-the-file-that-isn-t-what-it-claims-to-be-wcuzhbldv","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/file-upload-security-in-php-and-laravel-the-file-that-isn-t-what-it-claims-to-be-wcuzhbldv"},"datePublished":"2026-07-27T17:57:27.931Z","dateModified":"2026-09-14T07:03:42.409Z","description":"File uploads are one of the most dangerous attack vectors in PHP applications. 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As a second layer, configure the web server to deny PHP execution in any upload directory using an Nginx location block or an Apache .htaccess rule disabling the PHP engine. daily.dev surfaces practical hardening patterns like this for developers securing PHP upload endpoints."}},{"@type":"Question","name":"Why is checking $_FILES['type'] not safe for validating uploaded file types in PHP?","acceptedAnswer":{"@type":"Answer","text":"The type field in the $_FILES array is a browser-supplied value that an attacker fully controls, so they can set it to image/jpeg while uploading a PHP shell script and pass the check. The reliable alternative is PHP's finfo extension, which reads the actual file bytes to determine the real MIME type rather than trusting the client. 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