cbcvebase.
CVE-2018-6389
published 2018-02-06

CVE-2018-6389: In WordPress through 4.9.2, unauthenticated attackers can cause a denial of service (resource consumption) by using the large list of registered .js files…

PriorityP267high7.5CVSS 3.0
AVNACLPRNUINSUCNINAH
EXPLOIT
EPSS
73.10%
99.4th percentile
In WordPress through 4.9.2, unauthenticated attackers can cause a denial of service (resource consumption) by using the large list of registered .js files (from wp-includes/script-loader.php) to construct a series of requests to load every file many times.

Affected

2 ranges
VendorProductVersion rangeFixed in
debianwordpress
wordpresswordpress<= 4.9.2

Detection & IOCsextracted from sources · hover to see the quote

path/wp-admin/load-scripts.php
url/wp-admin/load-scripts.php?c=1&load%5B%5D=eutil,common,wp-a11y,sack,quicktag,colorpicker,editor,wp-fullscreen-stu,wp-ajax-response,wp-api-request,wp-pointer,autosave,heartbeat,wp-auth-check,wp-lists,prototype,scriptaculous-root,scriptaculous-builder,scriptaculous-dragdrop,scriptaculous-effects,scriptaculous-slider,scriptaculous-sound,scriptaculous-controls,scriptaculous,cropper,jquery,jquery-core,jquery-migrate,jquery-ui-core,jquery-effects-core,jquery-effects-blind,jquery-effects-bounce,jquery-effects-clip,jquery-effects-drop,jquery-effects-explode,jquery-effects-fade,jquery-effects-fold,jquery-effects-highlight,jquery-effects-puff,jquery-effects-pulsate,jquery-effects-scale,jquery-effects-shake,jquery-effects-size,jquery-effects-slide,jquery-effects-transfer,jquery-ui-accordion,jquery-ui-autocomplete,jquery-ui-button,jquery-ui-datepicker,jquery-ui-dialog,jquery-ui-draggable,jquery-ui-droppable,jquery-ui-menu,jquery-ui-mouse,jquery-ui-position,jquery-ui-progressbar,jquery-ui-resizable,jquery-ui-selectable,jquery-ui-selectmenu,jquery-ui-slider,jquery-ui-sortable,jquery-ui-spinner,jquery-ui-tabs,jquery-ui-tooltip,jquery-ui-widget,jquery-form,jquery-color,schedule,jquery-query,jquery-serialize-object,jquery-hotkeys,jquery-table-hotkeys,jquery-touch-punch,suggest,imagesloaded,masonry,jquery-masonry,thickbox,jcrop,swfobject,moxiejs,plupload,plupload-handlers,wp-plupload,swfupload,swfupload-all,swfupload-handlers,comment-repl,json2,underscore,backbone,wp-util,wp-sanitize,wp-backbone,revisions,imgareaselect,mediaelement,mediaelement-core,mediaelement-migrat,mediaelement-vimeo,wp-mediaelement,wp-codemirror,csslint,jshint,esprima,jsonlint,htmlhint,htmlhint-kses,code-editor,wp-theme-plugin-editor,wp-playlist,zxcvbn-async,password-strength-meter,user-profile,language-chooser,user-suggest,admin-ba,wplink,wpdialogs,word-coun,media-upload,hoverIntent,customize-base,customize-loader,customize-preview,customize-models,customize-views,customize-controls,customize-selective-refresh,customize-widgets,customize-preview-widgets,customize-nav-menus,customize-preview-nav-menus,wp-custom-header,accordion,shortcode,media-models,wp-embe,media-views,media-editor,media-audiovideo,mce-view,wp-api,admin-tags,admin-comments,xfn,postbox,tags-box,tags-suggest,post,editor-expand,link,comment,admin-gallery,admin-widgets,media-widgets,media-audio-widget,media-image-widget,media-gallery-widget,media-video-widget,text-widgets,custom-html-widgets,theme,inline-edit-post,inline-edit-tax,plugin-install,updates,farbtastic,iris,wp-color-picker,dashboard,list-revision,media-grid,media,image-edit,set-post-thumbnail,nav-menu,custom-header,custom-background,media-gallery,svg-painter&ver=4.9
filenameload-scripts.php
filenamewp-includes/script-loader.php
  • Detect exploitation attempts by matching HTTP GET requests to /wp-admin/load-scripts.php with an excessively long query string (>=1000 chars), indicative of the full JS bundle DoS payload.
  • A single exploit request causes the server to perform 181 I/O actions and return ~4MB of data; monitor for anomalously large responses from /wp-admin/load-scripts.php as a detection signal.
  • The exploit rotates through a known set of User-Agent strings; correlating these UAs with high-volume requests to load-scripts.php can aid detection.
  • Requests include Cache-Control: no-cache header to bypass caching and force server-side I/O on every request; use this as an additional filter alongside load-scripts.php targeting.
  • ·The vulnerability has never been acknowledged by WordPress authors and there is no mitigation in the WordPress codebase itself; hardening must be applied at the web server or WAF layer.
  • ·Caching the load-scripts.php response at the hosting/CDN layer effectively neutralises the attack by eliminating repeated server-side I/O.

CVSS provenance

nvdv3.07.5HIGHCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
nvdv2.05.0MEDIUMAV:N/AC:L/Au:N/C:N/I:N/A:P
osv7.5HIGH
vendor_debian7.5LOW
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