File size: Varies
File type: EXE
Memory resident: Yes
Initial samples received date: 26 Apr 2011
Payload: Downloads files
Arrival Details
This Trojan may be downloaded by the following malware/grayware from remote sites:
It may be dropped by other malware.
It may be unknowingly downloaded by a user while visiting malicious websites.
Installation
This Trojan drops the following copies of itself into the affected system:
- %System%\{random file name}.exe
- %System%\midimap32.exe
- %System%\shmedia32.exe
- %User Profile%\Application Data\SysWin\lsass.exe
(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.. %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.)
It drops the following non-malicious files:
(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)
It creates the following folders:
- %User Profile%\Application Data\SysWin
(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.)
It terminates the execution of the copy it initially executed and executes the copy it drops instead.
Autostart Technique
This Trojan registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\HidServ32
Type = 10
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\HidServ32
Start = 2
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\HidServ32
ErrorControl = 0
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\HidServ32
ImagePath = "%System%\{random file name}.exe"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\HidServ32
DisplayName = "Human Interface Device Access "
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\HidServ32
ObjectName = "LocalSystem"
It registers as a system service to ensure its automatic execution at every system startup by adding the following registry keys:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\HidServ32
Other System Modifications
This Trojan adds the following registry keys:
HKEY_CLASSES_ROOT\.fsharproj
HKEY_CLASSES_ROOT\Cfbbbjkdkl
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer
982bc1da = {random values}
HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
XMLHTTP_UUID_Default = {random values}
HKEY_CURRENT_USER\Identities
Curr version = "35"
HKEY_CURRENT_USER\Identities
Last Date = "{last date of execution}"
HKEY_CURRENT_USER\Identities
Send Inst = "ok"
HKEY_CURRENT_USER\Identities
Inst Date = "{installation date}"
HKEY_CURRENT_USER\Identities
Popup count = "0"
HKEY_CURRENT_USER\Identities
Popup time = "0"
HKEY_CURRENT_USER\Identities
Popup date = "0"
It creates the following registry entry(ies) to bypass Windows Firewall:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\DomainProfile\AuthorizedApplications\
List
%System%\{random file name}.exe = "%System%\{random file name}.exe:*:Enabled:Windows Update Service"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%System%\{random file name}.exe = "%System%\{random file name}.exe:*:Enabled:Windows Update Service"
Download Routine
This Trojan connects to the following URL(s) to download its configuration file:
- http://{BLOCKED}.1.173/doit/{random characters}
- http://{BLOCKED}.1.174/tornado/{random characters}
It saves the files it downloads using the following names:
- %System%\{random folder}\frt{random number}.rar
(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)
NOTES:
The downloaded configuration file contains the URLs containing the update. The URLs are saved in the file %System%\1652938413. However, the configuration file is not saved in the computer. It downloads updates of itself from the URLs in the configuration file. The downloaded update is a compressed RAR archive. It uses the dropped file %System%\unrar.exe to extract the compressed updated copy of the malware. Trend Micro detects the downloaded update as either TROJ_TRACUR.SMA or TROJ_TRACUR.SMB.
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