Headline
CVE-2023-28115: Release v1.4.2 · KnpLabs/snappy
Snappy is a PHP library allowing thumbnail, snapshot or PDF generation from a url or a html page. Prior to version 1.4.2, Snappy is vulnerable to PHAR deserialization due to a lack of checking on the protocol before passing it into the file_exists() function. If an attacker can upload files of any type to the server he can pass in the phar:// protocol to unserialize the uploaded file and instantiate arbitrary PHP objects. This can lead to remote code execution especially when snappy is used with frameworks with documented POP chains like Laravel/Symfony vulnerable developer code. If a user can control the output file from the generateFromHtml() function, it will invoke deserialization. This vulnerability is capable of remote code execution if Snappy is used with frameworks or developer code with vulnerable POP chains. It has been fixed in version 1.4.2.
Actions
Automate any workflow
Packages
Host and manage packages
Security
Find and fix vulnerabilities
Codespaces
Instant dev environments
Copilot
Write better code with AI
Code review
Manage code changes
Issues
Plan and track work
Discussions
Collaborate outside of code
* Explore
* All features
* Documentation
* GitHub Skills
* Blog
For
Enterprise
Teams
Startups
Education
By Solution
CI/CD & Automation
DevOps
DevSecOps
Case Studies
Customer Stories
Resources
GitHub Sponsors
Fund open source developers
* The ReadME Project
GitHub community articles
* Repositories
* Topics
* Trending
* Collections
- Pricing
Related news
## Description snappy is vulnerable to PHAR deserialization due to a lack of checking on the protocol before passing it into the `file_exists()` function. If an attacker can upload files of any type to the server he can pass in the phar:// protocol to unserialize the uploaded file and instantiate arbitrary PHP objects. This can lead to remote code execution especially when snappy is used with frameworks with documented POP chains like Laravel/Symfony vulnerable developer code. If user can control the output file from the `generateFromHtml()` function, it will invoke deserialization. ## Proof of Concept Install Snappy via composer require `knplabs/knp-snappy`. After that, under snappy directory, create an `index.php` file with this vulnerable code. ```php <?php // index.php // include autoloader require __DIR__ . '/vendor/autoload.php'; // reference the snappy namespace use Knp\Snappy\Pdf; // vulnerable object class VulnerableClass { public $fileName; public $callback; ...