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Improper sanitize of SVG files during content upload ('Cross-site Scripting') in sylius/sylius

Moderate severity GitHub Reviewed Published Mar 14, 2022 in Sylius/Sylius • Updated Jan 27, 2023

Package

composer Sylius/Sylius (Composer)

Affected versions

< 1.9.10
>= 1.10.0, < 1.10.11
>= 1.11.0, < 1.11.2

Patched versions

1.9.10
1.10.11
1.11.2

Description

Impact

There is a possibility to upload an SVG file containing XSS code in the admin panel. In order to perform an XSS attack, the file itself has to be opened in a new card (or loaded outside of the IMG tag). The problem applies both to the files opened on the admin panel and shop pages.

Patches

The issue is fixed in versions: 1.9.10, 1.10.11, 1.11.2, and above.

Workarounds

If there is a need to upload an SVG image type, on-upload sanitization has to be added. The way to achieve this is to require a library that will do the trick:

composer require enshrined/svg-sanitize

The second step is all about performing a file content sanitization before writing it to the filesystem. It can be done by overwriting the service:

<?php

declare(strict_types=1);

namespace App\Uploader;

use enshrined\svgSanitize\Sanitizer;
use Gaufrette\Filesystem;
use Sylius\Component\Core\Generator\ImagePathGeneratorInterface;
use Sylius\Component\Core\Generator\UploadedImagePathGenerator;
use Sylius\Component\Core\Model\ImageInterface;
use Sylius\Component\Core\Uploader\ImageUploaderInterface;
use Symfony\Component\HttpFoundation\File\File;
use Webmozart\Assert\Assert;

final class ImageUploader implements ImageUploaderInterface
{
    private const MIME_SVG_XML = 'image/svg+xml';
    private const MIME_SVG = 'image/svg';

    /** @var Filesystem */
    protected $filesystem;

    /** @var ImagePathGeneratorInterface */
    protected $imagePathGenerator;

    /** @var Sanitizer */
    protected $sanitizer;

    public function __construct(
        Filesystem $filesystem,
        ?ImagePathGeneratorInterface $imagePathGenerator = null
    ) {
        $this->filesystem = $filesystem;

        if ($imagePathGenerator === null) {
            @trigger_error(sprintf(
                'Not passing an $imagePathGenerator to %s constructor is deprecated since Sylius 1.6 and will be not possible in Sylius 2.0.', self::class
            ), \E_USER_DEPRECATED);
        }

        $this->imagePathGenerator = $imagePathGenerator ?? new UploadedImagePathGenerator();
        $this->sanitizer = new Sanitizer();
    }

    public function upload(ImageInterface $image): void
    {
        if (!$image->hasFile()) {
            return;
        }

        /** @var File $file */
        $file = $image->getFile();

        Assert::isInstanceOf($file, File::class);

        $fileContent = $this->sanitizeContent(file_get_contents($file->getPathname()), $file->getMimeType());

        if (null !== $image->getPath() && $this->has($image->getPath())) {
            $this->remove($image->getPath());
        }

        do {
            $path = $this->imagePathGenerator->generate($image);
        } while ($this->isAdBlockingProne($path) || $this->filesystem->has($path));

        $image->setPath($path);

        $this->filesystem->write($image->getPath(), $fileContent);
    }

    public function remove(string $path): bool
    {
        if ($this->filesystem->has($path)) {
            return $this->filesystem->delete($path);
        }

        return false;
    }

    protected function sanitizeContent(string $fileContent, string $mimeType): string
    {
        if (self::MIME_SVG_XML === $mimeType || self::MIME_SVG === $mimeType) {
            $fileContent = $this->sanitizer->sanitize($fileContent);
        }

        return $fileContent;
    }

    private function has(string $path): bool
    {
        return $this->filesystem->has($path);
    }

    /**
     * Will return true if the path is prone to be blocked by ad blockers
     */
    private function isAdBlockingProne(string $path): bool
    {
        return strpos($path, 'ad') !== false;
    }
}

After that, register service in the container:

services:
    sylius.image_uploader:
        class: App\Uploader\ImageUploader
        arguments:
            - '@gaufrette.sylius_image_filesystem'
            - '@Sylius\Component\Core\Generator\ImagePathGeneratorInterface'

For more information

If you have any questions or comments about this advisory:

References

@lchrusciel lchrusciel published to Sylius/Sylius Mar 14, 2022
Published by the National Vulnerability Database Mar 14, 2022
Published to the GitHub Advisory Database Mar 14, 2022
Reviewed Mar 14, 2022
Last updated Jan 27, 2023

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

EPSS score

0.104%
(43rd percentile)

CVE ID

CVE-2022-24749

GHSA ID

GHSA-4qrp-27r3-66fj

Source code

Credits

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