Synology StorageManager smart.cgi Remote Command Execution

### Vulnerability SummaryThe following advisory describes a remote command execution vulnerability found in Synology StorageManager.Storage Manager is “a management application that helps you organize and monitor the storage capacity on your Synology NAS. Depending on the model and number of installed hard drives, Storage Manager helps you accomplish the following tasks:* Create different types of RAID and non-RAID storage configurations, such as volumes, disk/RAID groups, iSCSI LUNs, and iSCSI Targets.* Monitor the overall storage usage of your Synology NAS.* Inspect the health of installed hard drives and solid state drives.* Use advanced options, such as hot spare drives, SSD TRIM, SSD cache, and more.”### CreditAn independent security researcher has reported this vulnerability to Beyond Security’s SecuriTeam Secure Disclosure program### Vendor responseSynology has released patches to address this vulnerability – DSM 5.2-5967-5For more information: https://www.synology.com/en-global/releaseNote/DS210+### Vulnerability detailsUser controlled input is not sufficiently sanitized, and then passed to execve function.Successful exploitation of this vulnerability enables a remote unauthenticated user to run commands as root on the machine.The vulnerable parameter can be found in `/webman/modules/StorageManager/smart.cgi` with parameter `action=apply&operation=quick&disk=%2Fdev%2Fsda`Strace“`execve("/usr/syno/bin/smartctl", ["/usr/syno/bin/smartctl", "-d", "ata", "-t", "short", "/dev/sda"], ["GATEWAY_INTERFACE=CGI/1.1","CONTENT_TYPE=application/x-www-form-urlencoded; charset=UTF-8","HTTP_X_REQUESTED_WITH=XMLHttpRequest", "REMOTE_ADDR=192.168.56.1","QUERY_STRING=", "REMOTE_PORT=34708", "DOCUMENT_ROOT=/usr/syno/synoman","HTTP_USER_AGENT=Mozilla/5.0 (X11; Linux i686; rv:47.0) Gecko/20100101Firefox/47.0", "SERVER_SIGNATURE=","HTTP_ACCEPT=text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8", "CONTENT_LENGTH=42","SCRIPT_FILENAME=/usr/syno/synoman/webman/modules/StorageManager/smart.cgi","HTTP_HOST=192.168.56.101:5000","REQUEST_URI=/webman/modules/StorageManager/smart.cgi","SERVER_SOFTWARE=Apache", "HTTP_CONNECTION=close","MOD_X_SENDFILE_ENABLED=yes","PATH=/sbin:/bin:/usr/sbin:/usr/bin:/usr/syno/sbin:/usr/syno/bin:/usr/local/sbin:/usr/local/bin", "HTTP_ACCEPT_LANGUAGE=en-US,en;q=0.5","HTTP_REFERER=http://192.168.56.101:5000/webman/index.cgi","SERVER_PROTOCOL=HTTP/1.1", "HTTP_ACCEPT_ENCODING=gzip, deflate","SCRIPT_URI=http://192.168.56.101:5000/webman/modules/StorageManager/smart.cgi", "SCRIPT_URL=/webman/modules/StorageManager/smart.cgi","REQUEST_METHOD=POST", "SERVER_ADMIN=admin", "SERVER_ADDR=192.168.56.101","PWD=/usr/syno/synoman/webman/modules/StorageManager", "SERVER_PORT=5000","SCRIPT_NAME=/webman/modules/StorageManager/smart.cgi","SERVER_NAME=192.168.56.101"]) = 0“`