Stored XSS viva cshtm file upload in star7th/showdoc
Reported on
Mar 14th 2022
Description
This is a bypass of the report:https://huntr.dev/bounties/8702e2bf-4af2-4391-b651-c8c89e7d089e/. Here the upload functionality allows the malicious files with the extension .cshtm which leads to Stored XSS.
Proof of Concept
1.First, open your text file/notepad and paste the below payload and save it as XSS.cshtm :
<html>
<script>alert(1337)</script>
<script>alert(document.domain)</script>
<script>alert(document.location)</script>
<script>alert('XSS_by_Samprit Das')</script>
</html>
2.Then go to https://www.showdoc.com.cn/ and login with your account.
3.Afther that navigate to file library (https://www.showdoc.com.cn/attachment/index)
4.In the File Library page, click the Upload button and choose the XSS.cshtm
5.After uploading the file, click on the check button to open that file in a new tab.
PoC URL
https://img.showdoc.cc/622ebe1b26479_622ebe1b2646f.cshtm?e=1647234162&token=-YdeH6WvESHZKz-yUzWjO-uVV6A7oVrCN3UXi48F:u3jx4rpeao3gm0GikHZ_L7tlI3Y=
Impact
This allows attackers to execute malicious scripts in the user's browser and it can lead to session hijacking, sensitive data exposure, and worse.
