1. Be easy to install and use; the tool runs on Windows and requires no 3rd party libraries
2. Support the most common protocols used by malware
3. Perform all activity on the local machine to avoid the need for a second virtual machine
4. Provide python extensions for adding new or custom protocols
5. Keep the malware running so that you can observe as much of its functionality as possible
6. Have a flexible configuration, but no required configuration

• Supports DNS, HTTP, and SSL
• HTTP server always serves a file and tries to serve a meaningful file; if the malware request a .jpg then a properly formatted .jpg is served, etc.  The files being served are user configurable.
• Ability to redirect all traffic to the localhost, including traffic destined for a hard-coded IP address.
• Python extensions, including a sample extension that implements SMTP and SMTP over SSL.
• Built in ability to create a capture file (.pcap) for packets on localhost.
• Dummy listener that will listen for traffic on any port, auto-detect and decrypt SSL traffic and display the content to the console.

• Monitor your entire IT infrastructure
• Spot problems before they occur
• Know immediately when problems arise
• Share availability data with stakeholders
• Detect security breaches
• Plan and budget for IT upgrades
• Reduce downtime and business losses

Responder is a LLMNR and NBT-NS poisoner, with built-in HTTP/SMB/MSSQL/FTP/LDAP rogue authentication server supporting NTLMv1/NTLMv2/LMv2, Extended Security NTLMSSP and Basic HTTP authentication.

FEATURES

• Built-in SMB Auth server. Supports NTLMv1, NTLMv2 hashes with Extended Security NTLMSSP by default. Successfully tested from Windows 95 to Server 2012 RC, Samba and Mac OSX Lion. Clear text password is supported for NT4, and LM hashing downgrade when the --lm option is set to On. This functionality is enabled by default when the tool is launched.
• Built-in MSSQL Auth server. In order to redirect SQL Authentication to this tool, you will need to set the option -r to On(NBT-NS queries for SQL Server lookup are using the Workstation Service name suffix) for systems older than windows Vista (LLMNR will be used for Vista and higher). This server supports NTLMv1, LMv2 hashes. This functionality was successfully tested on Windows SQL Server 2005 & 2008.
• Built-in HTTP Auth server. In order to redirect HTTP Authentication to this tool, you will need to set the option -r to On for Windows version older than Vista (NBT-NS queries for HTTP server lookup are sent using the Workstation Service name suffix). For Vista and higher, LLMNR will be used. This server supports NTLMv1, NTLMv2 hashes and Basic Authentication. This server was successfully tested on IE 6 to IE 10, Firefox, Chrome, Safari. Note: This module also works for WebDav NTLM authentication issued from Windows WebDav clients (WebClient). You can now send your custom files to a victim.
• Built-in HTTPS Auth server. In order to redirect HTTPS Authentication to this tool, you will need  to set the -r option to On for Windows versions older than Vista (NBT-NS  queries for HTTP server lookups are sent using the Workstation Service  name suffix). For Vista and higher, LLMNR will be used. This server  supports NTLMv1, NTLMv2, and Basic Authentication. This server  was successfully tested on IE 6 to IE 10, Firefox, Chrome, and Safari.  The folder Cert/ was added and contain 2 default keys, including a dummy  private key. This is intentional, the purpose is to have Responder  working out of the box. A script was added in case you need to generate  your own self signed key pair.
• Built-in LDAP Auth server. In order to redirect LDAP Authentication to this tool, you will need to set the option -r to On for Windows version older than Vista (NBT-NS queries for HTTP server lookup are sent using the Workstation Service name suffix). For Vista and higher, LLMNR will be used. This server supports NTLMSSP hashes and Simple Authentication (clear text authentication). This server was successfully tested on Windows Support tool "ldp" and LdapAdmin.
• Built-in FTP Auth server. This module will collect FTP clear text credentials.
• Built-in small DNS server. This server will answer type A queries. This is really handy when it's combined with ARP spoofing.
• All hashes are printed to stdout and dumped in an unique file John Jumbo compliant, using this format: (SMB or MSSQL or HTTP)-(ntlm-v1 or v2 or clear-text)-Client_IP.txt The file will be located in the current folder.
• Responder will logs all its activity to a file Responder-Session.log.
• When the option -f is set to "On", Responder will fingerprint every host who issued an LLMNR/NBT-NS query. All capture modules still work while in fingerprint mode.
• Browser Listener finds the PDC in stealth mode.
• Icmp Redirect for MITM on Windows XP/2003 and earlier Domain members. This attack combined with the DNS module is pretty effective.
• WPAD rogue transparent proxy server. This module will capture all HTTP requests from anyone launching Internet Explorer on the network. This module is higly effective. You can now send your custom Pac script to a victim and inject HTML into the server's responses. See Responder.conf. This module is now enabled by default.
• Analyze mode: This module allows you to see NBT-NS, BROWSER, LLMNR requests from which workstation to which workstation without poisoning any requests. Also, you can map domains, MSSQL servers, workstations passively, see if ICMP Redirects attacks are plausible on your subnet.
• Responder is now using a configuration file. See Responder.conf.
• Built-in POP3 auth server. This module will collect POP3 plaintext credentials
• Built-in SMTP auth server. This module will collect PLAIN/LOGIN clear text credentials.
  
  

CONSIDERATIONS

• This tool listen on several port: UDP 137, UDP 138, UDP 53, UDP/TCP 389,TCP 1433, TCP 80, TCP 139, TCP 445, TCP 21, TCP 3141,TCP 25, TCP 110, TCP 587 and Multicast UDP 5553. If you run Samba on your system, stop smbd and nmbd and all other services listening on these ports. For Ubuntu users: Edit this file /etc/NetworkManager/NetworkManager.conf and comment the line : "dns=dnsmasq". Then kill dnsmasq with this command (as root): killall dnsmasq -9
• Any rogue server can be turn off in Responder.conf.
• You can set a network interface via command line switch -I. Default is all.
• This tool is not meant to work on Windows.