Monday, October 28, 2013

File p2p-conficker

Script types: hostrule
Categories: default, safe
Download: http://nmap.org/svn/scripts/p2p-conficker.nse

User Summary

Checks if a host is infected with Conficker.C or higher, based on Conficker's peer to peer communication.
When Conficker.C or higher infects a system, it opens four ports: two TCP and two UDP. The ports are random, but are seeded with the current week and the IP of the infected host. By determining the algorithm, one can check if these four ports are open, and can probe them for more data.
Once the open ports are found, communication can be initiated using Conficker's custom peer to peer protocol. If a valid response is received, then a valid Conficker infection has been found.
This check won't work properly on a multihomed or NATed system because the open ports will be based on a nonpublic IP. The argument checkall tells Nmap to attempt communication with every open port (much like a version check) and the argument realip tells Nmap to base its port generation on the given IP address instead of the actual IP.
By default, this will run against a system that has a standard Windows port open (445, 139, 137). The arguments checkall and checkconficker will both perform checks regardless of which port is open, see the args section for more information.
Note: Ensure your clock is correct (within a week) before using this script!
The majority of research for this script was done by Symantec Security Response, and some was taken from public sources (most notably the port blacklisting was found by David Fifield). A big thanks goes out to everybody who contributed!

Script Arguments

realip

An IP address to use in place of the one known by Nmap.

checkall

If set to 1 or true, attempt to communicate with every open port.

checkconficker

If set to 1 or true, the script will always run on active hosts, it doesn't matter if any open ports were detected.

randomseed, smbbasic, smbport, smbsign

See the documentation for the smb library.

smbdomain, smbhash, smbnoguest, smbpassword, smbtype, smbusername

See the documentation for the smbauth library.

Example Usage

# Run the scripts against host(s) that appear to be Windows
nmap --script p2p-conficker,smb-os-discovery,smb-check-vulns --script-args=safe=1 -T4 -vv -p445 <host>
sudo nmap -sU -sS --script p2p-conficker,smb-os-discovery,smb-check-vulns --script-args=safe=1 -vv -T4 -p U:137,T:139 <host>

# Run the scripts against all active hosts (recommended)
nmap -p139,445 -vv --script p2p-conficker,smb-os-discovery,smb-check-vulns --script-args=checkconficker=1,safe=1 -T4 <host>

# Run scripts against all 65535 ports (slow)
nmap --script p2p-conficker,smb-os-discovery,smb-check-vulns -p- --script-args=checkall=1,safe=1 -vv -T4 <host>

# Base checks on a different ip address (NATed)
nmap --script p2p-conficker,smb-os-discovery -p445 --script-args=realip=\"192.168.1.65\" -vv -T4 <host>

Script Output

Clean machine (results printed only if extra verbosity ("-vv")is specified):
Host script results:
|  p2p-conficker: Checking for Conficker.C or higher...
|  | Check 1 (port 44329/tcp): CLEAN (Couldn't connect)
|  | Check 2 (port 33824/tcp): CLEAN (Couldn't connect)
|  | Check 3 (port 31380/udp): CLEAN (Failed to receive data)
|  | Check 4 (port 52600/udp): CLEAN (Failed to receive data)
|_ |_ 0/4 checks: Host is CLEAN or ports are blocked

Infected machine (results always printed):
Host script results:
|  p2p-conficker: Checking for Conficker.C or higher...
|  | Check 1 (port 18707/tcp): INFECTED (Received valid data)
|  | Check 2 (port 65273/tcp): INFECTED (Received valid data)
|  | Check 3 (port 11722/udp): INFECTED (Received valid data)
|  | Check 4 (port 12690/udp): INFECTED (Received valid data)
|_ |_ 4/4 checks: Host is likely INFECTED

Requires


Author: Ron Bowes (with research from Symantec Security Response)
License: Same as Nmap--See http://nmap.org/book/man-legal.html

hostrule

hostrule (host)
For a hostrule, simply use the 'smb' ports as an indicator, unless the user overrides it

Parameters

  • host:

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