# Date: 20/08/2021
# Exploit Author: Davide Taraschi
# Vendor Homepage: https://wpschoolpress.com/
# Software Link: https://wpschoolpress.com/free-download/
# Version: up to 2.1.17 (non included)
# Tested on: Ubuntu 20.04 over WordPress 5.8 and apache2
# CVE : CVE-2021-24664
# Description:
The plugin sanitise some fields using a wordpress built-in function
called sanitize_text_field() but does not correctly escape them
before outputting in attributes, resulting in Stored Cross-Site
Scripting issues.
The function wp_sanitize_text_field() escape < and > but does
not escape characters like ", allowing an attacker to break a HTML
input tag and inject arbitrary javascript.
# PoC:
As admin,
- Add a new teacher attendance
(/wp-admin/admin.php?page=sch-teacherattendance), Tick the Absent
box and put the following payload in the Reason:
"style=animation-name:rotation onanimationstart=alert(/XSS/)//
The XSS will be triggered when adding another teacher attendance by
clicking on the Add button
- Add a new Student Attendance
(/wp-admin/admin.php?page=sch-attendance), tick the Absent box and
put the following payload in the Reason: "
style=animation-name:rotation onanimationstart=alert(/XSS/)//
The XSS will be triggered when adding another attendance by
clicking the 'Add/Update' button
- Add a new Subject Mark Field
(/wp-admin/admin.php?page=sch-settings&sc=subField) and put the
following payload in the 'Field': " autofocus
onfocus=alert(/XSS/)//
The XSS will be triggered when editing the created Subject Mark (ie
/admin.php?page=sch-settings&sc=subField&ac=edit&sid=3)
- Create a new Subject (/wp-admin/admin.php?page=sch-subject),
with the following payload in the Subject Name field: " autofocus
onfocus=alert(/XSS/)//
The XSS will be triggered when editing the Subject
- Create a new Exam (/wp-admin/admin.php?page=sch-exams) with
the following payload in the Exam Name Field: " autofocus
onfocus=alert(/XSS/)//
The XSS will be triggered when editing the Exam=20
Note that some of this XSS issues can be executed by a teacher (medium-privileged user), but since wordpress uses HTTPonly cookies is impossible to steal cookies.
