BKDR_SIMDA.SU

This backdoor arrives as an attachment to email messages spammed by other malware/grayware or malicious users. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It executes then deletes itself afterward.

It connects to a website to send and receive information. However, as of this writing, the said sites are inaccessible.

As of this writing, the said sites are inaccessible.

Arrival Details

This backdoor arrives as an attachment to email messages spammed by other malware/grayware or malicious users.

It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

This backdoor drops the following files:

• %User Profile%\Application Data\{random}.reg
• %User Profile%\Application Data\mcp.ico
• %User Profile%\Application Data\Mozilla\Firefox\Profiles\{random}\searchplugins\search.xml
• %Desktop%\Computer.lnk
• %User Temp%\{random}.sys - encrypted
• %User Temp%\{random}-{random}.exe - detected as TSPY_SIMDA.SUS
• %User Temp%\{random number}.tmp - detected as TROJ_SIMDA.SU
• %User Temp%\{random}.exe - detected as TROJ_SIMDA.SUSF

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.. %Desktop% is the desktop folder, where it usually is C:\Documents and Settings\{user name}\Desktop in Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\Desktop in Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.. %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

It drops the following copies of itself into the affected system:

• %User Profile%\Application Data\ScanDisc.exe
• %User Profile%\Application Data\{random}.exe
• %User Temp%\{Random Number}.tmp

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.. %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

It executes then deletes itself afterward.

Autostart Technique

This backdoor creates the following registry entries to enable automatic execution of dropped component at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\RunOnce
{random name} = "%User Profile%\Application Data\{random name}.exe"

Other System Modifications

This backdoor adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
System
ConsentPromptBehaviorAdmin = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
System
ConsentPromptBehaviorUser = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
System
EnableLUA = "0"

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows
update = "shortcut"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Tcpip\Parameters\
Interfaces\{GUID}
NameServer = "8.8.8.8"

(Note: The default value data of the said registry entry is "".)

Backdoor Routine

This backdoor connects to the following websites to send and receive information:

• {BLOCKED}.{BLOCKED}.116.81
• report.{pseudorandom}.com
• update.{pseudorandom}.com
• {BLOCKED}.{BLOCKED}.196.94
• {BLOCKED}.{BLOCKED}.173.222
• {BLOCKED}.{BLOCKED}.176.187

However, as of this writing, the said sites are inaccessible.

Download Routine

This backdoor connects to the following website(s) to download and execute a malicious file:

• http://update1.{BLOCKED}erlrcn.com/?abbr=RTK&action=download&setupType=umx&setupFileName=process_64.exe
• http://update1.{BLOCKED}ring.com/update_c1eec.exe

As of this writing, the said sites are inaccessible.

HOSTS File Modification

This backdoor modifies the system's HOSTS files to redirect users once the following Web site(s) are accessed:

• google-analytics.com
• bing.com
• findgala.com
• ad-emea.doubleclick.net
• statcounter.com
• ::1 localhost
• au.bing.com : {BLOCKED}.{BLOCKED}.68.97
• ca.bing.com : {BLOCKED}.{BLOCKED}.68.97
• dk.bing.com : {BLOCKED}.{BLOCKED}.68.97
• gb.bing.com : {BLOCKED}.{BLOCKED}.68.97
• google.at : {BLOCKED}.{BLOCKED}.87.103
• google.be : {BLOCKED}.{BLOCKED}.87.148
• google.ca : {BLOCKED}.{BLOCKED}.87.152
• google.ch : {BLOCKED}.{BLOCKED}.87.155
• google.co.in : {BLOCKED}.{BLOCKED}.87.103
• google.co.jp : {BLOCKED}.{BLOCKED}.87.103
• google.co.nz : {BLOCKED}.{BLOCKED}.87.103
• google.co.uk : {BLOCKED}.{BLOCKED}.87.103
• google.co.za : {BLOCKED}.{BLOCKED}.87.103
• google.com : {BLOCKED}.{BLOCKED}.87.103
• google.com.ar : {BLOCKED}.{BLOCKED}..87.103
• google.com.au : {BLOCKED}.{BLOCKED}..87.104
• google.com.br : {BLOCKED}.{BLOCKED}..87.109
• google.com.tr : {BLOCKED}.{BLOCKED}..87.103
• google.cz : {BLOCKED}.{BLOCKED}.87.103
• google.de : {BLOCKED}.{BLOCKED}.87.160
• google.dk : {BLOCKED}.{BLOCKED}.87.123
• google.es : {BLOCKED}.{BLOCKED}.87.103
• google.fi : {BLOCKED}.{BLOCKED}.87.103
• google.fr : {BLOCKED}.{BLOCKED}.87.154
• google.gr : {BLOCKED}.{BLOCKED}.87.103
• google.hu : {BLOCKED}.{BLOCKED}.87.103
• google.ie : {BLOCKED}.{BLOCKED}.87.170
• google.it : {BLOCKED}.{BLOCKED}.87.173
• google.nl : {BLOCKED}.{BLOCKED}.87.103
• google.no : {BLOCKED}.{BLOCKED}.87.103
• google.pl : {BLOCKED}.{BLOCKED}.87.103
• google.pt : {BLOCKED}.{BLOCKED}.87.103
• google.ro : {BLOCKED}.{BLOCKED}.87.103
• google.se : {BLOCKED}.{BLOCKED}.87.103
• gr.bing.com : {BLOCKED}.{BLOCKED}.68.97
• ir.bing.com : {BLOCKED}.{BLOCKED}.68.97
• it.bing.com : {BLOCKED}.{BLOCKED}.68.97
• pt.bing.com : {BLOCKED}.{BLOCKED}.68.97
• ro.bing.com : {BLOCKED}.{BLOCKED}.68.97
• www.bing.com : {BLOCKED}.{BLOCKED}.68.97
• www.google.at : {BLOCKED}.{BLOCKED}.87.147
• www.google.be : {BLOCKED}.{BLOCKED}.87.149
• www.google.ca : {BLOCKED}.{BLOCKED}.87.153
• www.google.ch : {BLOCKED}.{BLOCKED}.87.158
• www.google.co.in : {BLOCKED}.{BLOCKED}.87.147
• www.google.co.jp : {BLOCKED}.{BLOCKED}.87.147
• www.google.co.nz : {BLOCKED}.{BLOCKED}.87.147
• www.google.co.uk : {BLOCKED}.{BLOCKED}.87.147
• www.google.co.za : {BLOCKED}.{BLOCKED}.87.147
• www.google.com : {BLOCKED}.{BLOCKED}.87.99
• www.google.com.ar : {BLOCKED}.{BLOCKED}.87.147
• www.google.com.au : {BLOCKED}.{BLOCKED}.87.147
• www.google.com.br : {BLOCKED}.{BLOCKED}.87.150
• www.google.com.tr : {BLOCKED}.{BLOCKED}.87.147
• www.google.cz : {BLOCKED}.{BLOCKED}.87.147
• www.google.de : {BLOCKED}.{BLOCKED}.87.161
• www.google.dk : {BLOCKED}.{BLOCKED}.87.160
• www.google.es : {BLOCKED}.{BLOCKED}.87.147
• www.google.fi : {BLOCKED}.{BLOCKED}.87.147
• www.google.fr : {BLOCKED}.{BLOCKED}.87.134
• www.google.gr : {BLOCKED}.{BLOCKED}.87.147
• www.google.hu : {BLOCKED}.{BLOCKED}.87.147
• www.google.ie : {BLOCKED}.{BLOCKED}.87.177
• www.google.it : {BLOCKED}.{BLOCKED}.87.147
• www.google.nl : {BLOCKED}.{BLOCKED}.87.147
• www.google.no : {BLOCKED}.{BLOCKED}.87.147
• www.google.pl : {BLOCKED}.{BLOCKED}.87.147
• www.google.pt : {BLOCKED}.{BLOCKED}.87.147
• www.google.ro : {BLOCKED}.{BLOCKED}.87.147
• www.google.se : {BLOCKED}.{BLOCKED}.87.147

Information Theft

This backdoor gathers the following data:

• Windows Install Date
• Volume Information
• Language Information
• Computer Name
• Network Adapter
• SusClientId
• Product Id

Other Details

This backdoor checks for the presence of the following process(es):

• cv.exe
• irise.exe
• IrisSvc.exe
• wireshark.exe
• dumpcap.exe
• ZxSniffer.exe
• Aircrack-ng Gui.exe
• observer.exe
• tcpdump.exe
• WinDump.exe
• wspass.exe
• Regshot.exe
• ollydbg.exe
• PEBrowseDbg.exe
• windbg.exe
• DrvLoader.exe
• SymRecv.exe
• Syser.exe
• apis32.exe
• VBoxService.exe
• VBoxTray.exe
• SbieSvc.exe
• SbieCtrl.exe
• SandboxieRpcSs.exe
• SandboxieDcomLaunch.exe
• SUPERAntiSpyware.exe
• ERUNT.exe
• ERDNT.exe
• EtherD.exe
• Sniffer.exe
• CamtasiaStudio.exe
• CamRecorder.exe

NOTES:

This backdoor attempts to open the file %System Root%\cgvi5r6i\vgdgfd.72g, which may contain shell commands.

It redirects the following sites when accessed to a designated malware vector:

It checks for the existence of the following registry keys:

HKEY_CURRENT_USER\Software\CommView
HKEY_CURRENT_USER\SYSTEM\CurrentControlSet\Services\IRIS5
HKEY_CURRENT_USER\Software\eEye Digital Security
HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\
Uninstall\Wireshark
HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\
App Paths\wireshark.exe
HKEY_CURRENT_USER\SOFTWARE\ZxSniffer
HKEY_CURRENT_USER\SOFTWARE\Cygwin
HKEY_CURRENT_USER\SOFTWARE\Cygwin
HKEY_CURRENT_USER\SOFTWARE\B Labs\Bopup Observer
HKEY_CURRENT_USER\AppEvents\Schemes\Apps\Bopup Observer
HKEY_CURRENT_USER\Software\B Labs\Bopup Observer
HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\
Uninstall\Win Sniffer_is1
HKEY_CURRENT_USER\Software\Win Sniffer
HKEY_CURRENT_USER\SOFTWARE\Classes\
PEBrowseDotNETProfiler.DotNETProfiler
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\
Explorer\MenuOrder\Start Menu2\Programs\Debugging Tools for Windows (x86)
HKEY_CURRENT_USER\SYSTEM\CurrentControlSet\Services\SDbgMsg
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\
Explorer\MenuOrder\Start Menu2\Programs\APIS32
HKEY_CURRENT_USER\Software\Syser Soft
HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\
Uninstall\APIS32
HKEY_CURRENT_USER\SOFTWARE\APIS32
HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\
Uninstall\Oracle VM VirtualBox Guest Additions
HKEY_CURRENT_USER\SYSTEM\CurrentControlSet\Services\VBoxGuest
HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\
Uninstall\Sandboxie
HKEY_CURRENT_USER\SYSTEM\CurrentControlSet\Services\SbieDrv
HKEY_CURRENT_USER\Software\Classes\Folder\shell\sandbox
HKEY_CURRENT_USER\Software\Classes\*\shell\sandbox
HKEY_CURRENT_USER\SOFTWARE\SUPERAntiSpyware.com
HKEY_CURRENT_USER\SOFTWARE\Classes\SUPERAntiSpywareContextMenuExt.SASCon.1
HKEY_CURRENT_USER\SOFTWARE\SUPERAntiSpyware.com
HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\
Uninstall\ERUNT_is1

It also checks for loaded libraries:

• SBIEDLL.DLL
• SBIEDLLX.DLL
• DBGHELP.DLL

It also checks if the following information are equal:

• Computer Name = Sandbox
• User name = CurrentUser
• File name = file.exe

When a number of conditions are met, this backdoor executes in an infinite loop.

It appends the legitimate file %User Profile%\Application Data\Mozilla\Firefox\Profiles\{random}\prefs.js with user_pref(&"browser.search.selectedEngine&"http://{BLOCKED}la.com/?&uid={number}&q={searchTerms}");.