Trojan.HTML.INFOSTEALER.THDOABO

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

It creates an event. However, as of this writing, the said sites are inaccessible.

Arrival Details

This Trojan 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 Trojan drops the following files:

• %User Temp%\0.png
• %User Temp%\1.png
• %User Temp%\2.png
• %User Temp%\3.png
• %User Temp%\4.png
• %User Temp%\1-index.htm -> used to display the PNG files and run the CAB file
• %User Temp%\~tmp6.cab -> main payload; detected as Trojan.Win32.INFOSTEALER.THDOABO
• %AppDataLocal%\systemsrv7.txt -> copy of ~tmp6.cab

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %AppDataLocal% is the Local Application Data folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It adds the following processes:

• cmd.exe /c for %i in (*.chm) do (hh -decompile %temp% %~i)&&cmd /c %temp%/~tmp6.cab

It injects codes into the following process(es):

• {any process with access rights}
• {any process with access rights}
  • The malware will continually inject codes into available processes until two infected processes are synchronized.

Autostart Technique

This Trojan drops the following file(s) in the Windows User Startup folder to enable its automatic execution at every system startup:

• %User Startup%\systemsrv7.lnk -> pointed to systemsrv7.txt

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows 2003(32-bit), XP and 2000(32-bit), or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit), 10(64-bit).)

Dropping Routine

This Trojan drops the following file(s), which it uses for its keylogging routine:

• %04d%02d%02d%02d%02d%02d%03d.LOG -> format is current year, month, day, hour, minute, second, and millisecond

Other Details

This Trojan displays the following images:

• %User Temp%\0.png
• 
  
• %User Temp%\1.png
• 
  
• %User Temp%\2.png
• 
  
• %User Temp%\3.png
• 
  
• %User Temp%\4.png
• 
  
• http://{BLOCKED}ive.icu/downl/images/jpg_1.gif

It uploads files to the following website(s):

• http://{BLOCKED}ive.icu/upload10.php
  • %04d%02d%02d%02d%02d%02d%03d.LOG is uploaded.

It does the following:

• It injects the following DLLs into the target processes:
  • Mngr.dll -> responsible for injection and synchronization
  • Klgr.dll -> logs user keystrokes
  • Send.dll -> uploads to the URL stated
  • Auto.dll -> creates autostart technique
  • Dldr.dll -> searches for specific .exe, .bat, .cmd, .vbs, and .js files and executes them
  • Brsr.dll -> browses drives and directories
• It attempts to a load a certain Krrde.dll.

It creates the following event(s):

• e_tr10_{104 and higher}_0
• e_tr10_{104 and higher}_1
• e_tr10_{104 and higher}_2
  • Events are used to synchronize the two infected processes.

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