Impact
Malicious actors can exploit this vulnerability to write files within arbitrary directories on the
filesystem of the Shopware web container. This could allow them to gain persistent shell access
by uploading a PHP-shell file to an accessible folder.
It is important to note that this vulnerability is only present on on-premises installation of
Shopware and not present on the SaaS installation due to additional security checks being
implemented on the uploaded plugin files.
Description
A path traversal vulnerability allows malicious actors to access files and folders that are outside
the folder structure accessible to the affected function.
This vulnerability occurs when an application uses unfiltered user input to point to the path of a
specific file and retrieve it. This can result in gaining read/write access to sensitive information,
application code, back-end systems and other (critical) files on the operating system.
In certain cases, it is even possible to store arbitrary files outside the relevant directory
structure on the server in order to gain access to the server.
Applicability
The Plugin upload function in use by the Shopware application is vulnerable to path traversal.
Within the on-premises version of the Shopware application users are able to extend the
functionality of the application by installing ‘plugins’ also referred to as ‘apps’ or ‘extensions’.
These plugins can be installed using the official store or by uploading a zip file containing the
required files. To prevent path traversal the Shopware application implements a check that
effectively prohibits files containing ‘..’ characters from being uploaded. During review of the
source code, it was noticed that the check for the prohibited characters was only performed
from the third entry (index 2) of the uploaded Zip file. This means that the second entry (index
- within the Zip file can contain path traversal characters and thus allows files to be written in
directories outside of the intended plugins folder.
To exploit this vulnerability, an admin account with permissions to upload plugins, is required.
Reproduction
To reproduce this vulnerability, the steps below can be followed.
- Log in to an on-premises Shopware application with an admin account with permissions to
upload plugins.
- Create a malicious Zip file using the script provided in evidence 5.
- Upload the generated malicious Zip file as a new plugin within the application
- Access the filesystem of the Shopware application
- Navigate to the path below:
/var/www/html/custom/apps
- Notice that an ‘evil.php’ file has been extracted within this folder.
Pot. Fix
We should check all files for path traversal here: https://github.com/shopware/shopware/blob/trunk/src/Core/Framework/Plugin/PluginExtractor.php#L79 and not only start with the second index
e.g. for app validation we do that already: https://github.com/shopware/shopware/blob/trunk/src/Core/Framework/App/AppArchiveValidator.php#L55
Impact
Malicious actors can exploit this vulnerability to write files within arbitrary directories on the
filesystem of the Shopware web container. This could allow them to gain persistent shell access
by uploading a PHP-shell file to an accessible folder.
It is important to note that this vulnerability is only present on on-premises installation of
Shopware and not present on the SaaS installation due to additional security checks being
implemented on the uploaded plugin files.
Description
A path traversal vulnerability allows malicious actors to access files and folders that are outside
the folder structure accessible to the affected function.
This vulnerability occurs when an application uses unfiltered user input to point to the path of a
specific file and retrieve it. This can result in gaining read/write access to sensitive information,
application code, back-end systems and other (critical) files on the operating system.
In certain cases, it is even possible to store arbitrary files outside the relevant directory
structure on the server in order to gain access to the server.
Applicability
The Plugin upload function in use by the Shopware application is vulnerable to path traversal.
Within the on-premises version of the Shopware application users are able to extend the
functionality of the application by installing ‘plugins’ also referred to as ‘apps’ or ‘extensions’.
These plugins can be installed using the official store or by uploading a zip file containing the
required files. To prevent path traversal the Shopware application implements a check that
effectively prohibits files containing ‘..’ characters from being uploaded. During review of the
source code, it was noticed that the check for the prohibited characters was only performed
from the third entry (index 2) of the uploaded Zip file. This means that the second entry (index
directories outside of the intended plugins folder.
To exploit this vulnerability, an admin account with permissions to upload plugins, is required.
Reproduction
To reproduce this vulnerability, the steps below can be followed.
upload plugins.
/var/www/html/custom/apps
Pot. Fix
We should check all files for path traversal here: https://github.com/shopware/shopware/blob/trunk/src/Core/Framework/Plugin/PluginExtractor.php#L79 and not only start with the second index
e.g. for app validation we do that already: https://github.com/shopware/shopware/blob/trunk/src/Core/Framework/App/AppArchiveValidator.php#L55