[Full-disclosure] ASPR #2011-01-11-1: Remote Binary Planting in Multiple F-Secure Products

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PUBLIC

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ACROS Security Problem Report #2011-01-11-1
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ASPR #2011-01-11-1: Remote Binary Planting in Multiple F-Secure Products
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Document ID:     ASPR #2011-01-11-1-PUB
Vendor:          F-Secure Corp. (http://www.f-secure.com)
Target:          F-Secure Internet Security 2010 and 2011
                 F-Secure Anti-Virus 2010 and 2011
                 (and multiple other F-Secure products) 
Impact:          Remote execution of arbitrary code
Severity:        Very high
Status:          Official patch available, workarounds available
Discovered by:   Simon Raner of ACROS Security

CVSS score:      9.3 (HIGH) (AV:N/AC:M/Au:N/C:C/I:C/A:C)
CVE ID:          (unknown)
CWE ID:          CWE-426: Untrusted Search Path

Current version 
   http://www.acrossecurity.com/aspr/ASPR-2011-01-11-1-PUB.txt


Summary
=======

A "binary planting" [1] vulnerability in F-Secure Internet Security 2010 
and 2011, F-Secure Anti-Virus 2010 and 2011 and multiple other F-Secure 
products allows local or remote (even Internet-based) attackers to deploy 
and execute malicious code on Windows machines in the context of logged-on 
users.


Product Coverage
================

- Solutions based on F-Secure Protection Service for Consumers version 9
- Solutions based on F-Secure Protection Service for Business -
    Workstation security version 9
- Solutions based on F-Secure Protection Service for Business -
    Email and Server Security version 9
- Solutions based on F-Secure Protection Service for Business -
    Server Security version 9
- F-Secure Internet Security 2010 and 2011
- F-Secure Anti-Virus 2010 and 2011
- F-Secure Client Security 9.00-9.01
- F-Secure Anti-Virus for Workstations 9.00-9.01
- F-Secure Anti-Virus for Windows Servers 9.00
- F-Secure Anti-Virus for Citrix Servers 9.00


Analysis 
========

As a result of an incorrect dynamic link library loading in affected 
F-Secure products, an attacker can cause her malicious DLL to be loaded 
and executed on users' computers from local drives, remote Windows shares, 
and even shares located on Internet. 

This vulnerability is exploitable through other products that F-Secure 
products integrate with, most notably web browsers. One such example is a 
combination of Mozilla Firefox and F-Secure Internet Security 2011. When 
launched by double-clicking an .HTML file via Windows Explorer (or most 
any other popular file manager), Firefox is started with the current 
working directory (CWD) set to the folder where this file resides. If F-
Secure Internet Security is installed, Firefox displays its toolbar and 
allows the user to view and edit the "Browsing protection" settings. These 
get launched by Firefox and inherit its CWD, but they also integrate a 
vulnerable 3rd party library QtCore4.dll, which blindly tries to load 
wintab32.dll whether this library is present on the system or not. In the 
latter case (i.e., on most systems), this DLL is not found in either the 
Firefox folder (%PROGRAMFILES%\Mozilla Firefox\) or any one of the Windows 
system folders as specified by the search path, and is then looked for in 
the CWD. If found there, wintab32.dll (planted by the attacker) is loaded 
and executed.

(Note that Firefox is doing nothing wrong here. Its CWD is set 
automatically by Windows Explorer upon user's double-clicking the HTML 
file, as is the case with any other application.)

All a remote attacker has to do is plant a malicious DLL with a specific 
name (wintab32.dll) on a network share and get the user to open any .HTML 
file with Firefox from this network location - which should require 
minimal social engineering.

Windows systems by default have the Web Client service running - which 
makes remote network shares accessible via WebDAV -, thus the malicious 
DLL can also be deployed from an Internet-based network share as long as 
the intermediate firewalls allow outbound HTTP traffic to the Internet. 

A systematic attack could deploy malicious code to a large number of 
Windows workstations in a short period of time, possibly as an Internet 
worm.

Visit http://www.binaryplanting.com/ for more information on binary 
planting vulnerabilities and attacks.


Mitigating Factors 
==================

- A firewall blocking outbound WebDAV traffic (in addition to blocking all 
  Windows Networking protocols) could stop an Internet-based attack.

- Microsoft's CWDIllegalInDllSearch hotfix [2] can stop a network-based 
  exploitation of this vulnerability.


Solution 
========

F-Secure has issued a security bulletin [3] and published an update for
all affected products that fixes this issue.


Workaround 
==========

- Stopping the Web Client service could stop Internet-based attacks as 
  long as the network firewall stops outbound Microsoft Networking 
  protocols. This would not, however, stop remote LAN-based attacks where 
  the attacker is able to place a malicious DLL on a network share inside 
  the target (e.g., corporate) network.
  
- General recommendations for limiting or stopping binary planting attacks 
  are available at 
  http://www.binaryplanting.com/guidelinesAdministrators.htm


Related Services
================

ACROS is offering professional consulting on this issue to interested 
corporate and government customers. Typical questions we can help you 
answer are:

1) To what extent is your organization affected by this issue?

2) Is it possible to get remote code from the Internet launched inside 
   your network? Can this be demonstrated?

3) Have you adequately applied the remedies to remove the vulnerability?

4) Are there circumstances in your environment that might prevent the 
   effectiveness of this fix?

5) Are there other workarounds that you could implement to fix this issue 
   more efficiently and/or inexpensively?

6) Are your systems or applications vulnerable to other similar issues?


Interested parties are encouraged to ask for more information at 
security@xxxxxxxxxxxxxxxxxx


Background
==========

ACROS Security has performed an extensive Binary Planting research 
project, focused on various types of vulnerabilities where an attacker 
with low privileges can place (i.e., "plant") a malicious executable file 
(i.e., "binary") to some possibly remote location and get it launched by 
some vulnerable application running on user's computer. 

The research found that binary planting vulnerabilities are affecting a 
large percentage of Windows applications and often allowing for trivial 
exploitation: it identified ~520 remotely exploitable bugs in ~200 widely-
used Windows applications. A large majority of these vulnerabilties 
remain unfixed and publicly unknown at the time of this writing.

Find out more:
- http://www.binaryplanting.com
- http://blog.acrossecurity.com

Follow ACROS Security on Twitter to get immediate updates on the ongoing 
Binary Planting research and other research projects.
http://www.twitter.com/AcrosSecurity


References
==========

[1] Binary Planting - The Official Web Site
    http://www.binaryplanting.com/

[2] Microsoft's CWDIllegalInDllSearch hotfix
    http://support.microsoft.com/kb/2264107

[3] Security Advisory FSC-2010-4 - Binary planting vulnerability
    http://www.f-secure.com/en_EMEA/support/security-advisory/fsc-2010-
    4.html


Contact
=======

ACROS d.o.o.
Makedonska ulica 113
SI - 2000 Maribor

e-mail: security@xxxxxxxxxxxxxxxxx
web:    http://www.acrossecurity.com
phone:  +386 2 3000 280
fax:    +386 2 3000 282

ACROS Security PGP Key
   http://www.acrossecurity.com/pgpkey.asc
   [Fingerprint: FE9E 0CFB CE41 36B0 4720 C4F1 38A3 F7DD]

ACROS Security Advisories
   http://www.acrossecurity.com/advisories.htm


Disclaimer
==========

The content of this report is purely informational and meant only for the 
purpose of education and protection. ACROS d.o.o. shall in no event be 
liable for any damage whatsoever, direct or implied, arising from use or 
spread of this information. All identifiers (hostnames, IP addresses, 
company names, individual names etc.) used in examples and demonstrations 
are used only for explanatory purposes and have no connection with any 
real host, company or individual. In no event should it be assumed that 
use of these names means specific hosts, companies or individuals are 
vulnerable to any attacks nor does it mean that they consent to being used 
in any vulnerability tests. The use of information in this report is 
entirely at user's risk.


Revision History
================

January 11, 2011: Initial release


Copyright
=========

(c) 2011 ACROS d.o.o. Forwarding and publishing of this document is
permitted providing the content between "[BEGIN-ACROS-REPORT]" and
"[END-ACROS-REPORT]" marks remains unchanged.

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