http://citizenlab.org/2012/05/iranian-anti-censorship-software-simurgh-circulated-with-malicious-backdoor/

Iranian anti-censorship software ‘Simurgh’ circulated with malicious backdoor

Simurgh is an Iranian stand-alone proxy software for Microsoft Windows. It has 
been used mainly by Iranian users to bypass censorship since 2009. The 
downloadable file is less than 1 MB and can be downloaded within a reasonable 
amount of time even with a slow internet connection, which makes it convenient 
for many users in Iran. Simurgh runs without prior installation or 
administrator privileges on the computer and therefore, can be copied and used 
from a USB flash drive on any shared computer (i.e Internet cafes).

Simurgh is available for free download from its official website 
https://simurghesabz.net. After running the executable file, a user interface 
(see below) opens. When the user clicks “Start”, Simurgh will attempt to 
establish a secure connection. The web browser will then open a new window to 
provide users with a test page, confirming their secure connection originating 
from a different country.



It has recently come to our attention that this software is being recommended 
and circulated among Syrian Internet users for bypassing censorship in their 
country. This information led to the discovery and analysis of a back-doored 
version of this software.

The malicious copy will install the Simurgh software, but will also install an 
undesirable backdoor on the victim’s computer. This software is distributed as 
“Simurgh-setup.zip” and is identifiable via the following md5 and sha256 hashes:

5e2a714fdfc2309af843056e8c5ae7d3 Simurgh-setup.zip
9c1a238d87e3bad41708c2e98f753442a224ed9df994e1a34083b2bf336047e5 
Simurgh-setup.zip

When you unzip this file you are presented with Simurgh-setup.exe

379480c807812f3521466f7ff5ffa273 Simurgh-setup.exe
e20438a4cf90b67dab613451cc5b3bc35256413461dafdfc35425429d8d478df 
Simurgh-setup.exe

The installer from the most recent legitimate version of Simurgh looks like 
this:



Executing the malicious version starts an installation dialogue which looks 
like this:



In addition to creating a copy of Simurgh in:

C:\Program Files\Simurgh\Simurgh.exe

The malicious GUI installer drops 4 binaries in C:\windows\system32\drivers:

MSINET.OCX – 73da54b69911bdd08ea8bbbd508f815ef7cfa59c4684d75c1c602252ec88ee31
richtx32.ocx – 318cc48cbcfaba9592956e4298886823cc5f37626c770d6dadbcd224849680c5
shdocvw.dll – fdae6764d190bf265dbc2df352174ccdcc97b1680545e348f1ee1111b0808693
lsass.exe – 9320d247dd94f610f31037df8eda75fe79991f126d2e55d35a9532d09ff79896

The first three files are legitimate Microsoft system files which appear to be 
dependencies of the fourth, ‘lsass.exe’. This file is VB6 native code and is 
installed as an implant to allow persistent access to the victim’s computer and 
to provide data exfiltration capabilities.

As part of the installation the following registry entry is written which 
ensures the running of the Trojan on logon:

HKLM\software\microsoft\windows nt\currentversion\winlogon\shell explorer.exe 
C:\WINDOWS\system32\drivers\lsass.exe REG_SZ 0

On startup, ‘lsass.exe’ deletes ‘C:\WINDOWS\Media\Windows XP Start.wav’. This 
file is the ‘navigation’ sound in Explorer, IE, and other applications based on 
a common set of controls. Since ‘lsass.exe’ uses several of these controls, 
this is presumably done to prevent ‘clicking’ sounds during the operation of 
the implant. However, this will also lead to a lack of navigation sounds in 
other applications, where they would be expected.

In addition to ensuring persistence, lsass.exe enumerates basic details of the 
system (IP address, hostname, victim username) and provides keylogging 
functionality. This binary contains three javascript files which are written 
out as the text files:

C:\WINDOWS\system32\win.txt
C:\WINDOWS\system32\1.txt
C:\WINDOWS\system32\2.txt

These act as basic HTML templates for data mined from the victim’s system (such 
as keystrokes). Processing of ‘win.txt’ renames it to ‘upl.htm’ which is then 
sent via HTTP post request to a remote site registered with a Saudi Arabian ISP.

If this Trojan is found to be installed on a computer one must consider all 
online accounts (E-mail, banking etc) to have been compromised and it is 
advised that all online passwords be changed as soon as possible. While this 
Trojan is detected by most anti-virus software as malicious, AV software cannot 
always be guaranteed to clean up an infected system and a full re-install is 
suggested.

This Trojan has been specifically crafted to target people attempting to evade 
government censorship. Given the intended purpose of this software, users must 
be very careful if they have been infected by this Trojan. Additionally, they 
should be cautious about installing software, especially circumvention 
software, from untrusted sources. Where possible, software should be downloaded 
from trusted official websites over HTTPS. If checksums or cryptographic 
signatures are provided by the software vendor, these should be checked prior 
to installation.

About Morgan Marquis-Boire

Morgan Marquis-Boire is a security researcher and Technical Advisor at the 
Citizen Lab, Munk School of Global Affairs, University of Toronto. He works as 
a Security Engineer at Google specializing in Incident Response, Forensics and 
Malware Analysis. Recently, he has been working with the Electronic Frontier 
Foundation on issues surrounding dissident suppression in Syria.

Ronald Deibert
Director, the Citizen Lab 
and the Canada Centre for Global Security Studies
Munk School of Global Affairs
University of Toronto
(416) 946-8916
PGP: http://deibert.citizenlab.org/pubkey.txt
http://deibert.citizenlab.org/
twitter.com/citizenlab
r.deib...@utoronto.ca



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