TSPY_DECBAL.A

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

Arrival Details

This spyware 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 spyware drops the following file(s)/component(s):

• "%User Profile%\{hex values derived from username}.dat" - Log file
• "%User Profile%\{hex values derived from computer name}.dat" - Log file
• %User Profile%\InternetExplorer.lnk - Shortcut for dropped copy

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

• %User Profile%\iexplore.exe

(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 adds the following mutexes to ensure that only one of its copies runs at any one time:

• {hex values derived from username and computer name of affected machine}

Autostart Technique

This spyware adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer\Run
Internet Explorer = "%User Profile%\InternetExplorer.lnk" - If OS version is lower than Windows Vista

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run
Internet Explorer = "%User Profile%\InternetExplorer.lnk" - If OS version is lower than Windows Vista

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Windows
Load = "%User Profile%\InternetExplorer.lnk" - If OS version is Windows Vista and up

Stolen Information

This spyware sends the gathered information via HTTP POST to the following URL:

• http://{BLOCKED}st.ro/fisier.php?&co={hex values derived from computer name}_&us={hex values derived from username}_&av={hex values derived from installed AV product name}_&os={hex values derived from OS version and processor}_&tr2={hex values derived from track data}

NOTES:

It retrieves the logged information from its dropped log files.

The dropped log files are deleted after execution.

It uses the User Agent "Decebalv1.0."

OS Version may be any of the following:

• Windows 95
• Windows 98
• Windows Millenium
• Windows NT 3.51
• Windows NT 4.0
• Windows 2000
• Windows XP
• Windows 2003 (SERVER)
• Windows Vista
• Windows 7
• Windows 8
• Unknown

It checks if there are installed sandboxing and reverse egineering software present in the affected machine such as the following:

• Sandboxie
• Windbg
• Buster Sandbox Analyzer
• VMWare
• Joe Sandbox Desktop
• ThreatAnalyzer Features
• IDAPro+Bochs debugger
• Norman Sandbox

It also checks if the filename of the executed file is "sample."

If any of the following is found, it terminates itself.

It terminates running processes found in the following registry keys:

• Software\Microsoft\Windows\CurrentVersion\Run
• Software\Microsoft\Windows\CurrentVersion\Run
• Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\Run
• Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\Run
• Software\Microsoft\Windows NT\CurrentVersion\Windows
• Software\Microsoft\Windows NT\CurrentVersion\Windows

• .exe
• .com
• .pif
• .bat
• .cmd
• .scr

It also deletes the registry key where these running processes are found. After deleting the registry key, it will also delete the executable file of the running process.

It uses Luhn algorithm to validate credit card numbers in VBScript, which is used together with regular expression for RAM memory scrapping:

• 0000000000000
• 00000000000000
• 000000000000000
• 0000000000000000
• 00000000000000000
• 000000000000000000
• 0000000000000000000
• 22222222222222222
• 6666666666666
• 8888888888888888
• 5488888888888888
• 5399999999999999
• 30044444444444
• 5577777777777777
• 5544444444444444
• 5488888888888888
• 36999999999999
• 36111111111111
• 4844777777777777
• 4844444444444444
• 341111111111111
• 347777777777777
• 62000000000000000
• 6200000000000000000
• 6222222222222222222
• 6244444444444444444
• 4744870016311111
• 8811111111111111111
• 8833333333333333333
• 88999999999999999
• 5544444444444444
• 5577777777777777
• 4111111111111111
• 4222222222222
• 4555555555555
• 499999999999999
• 4026444444444444
• 4026777777777777

It scans for track data in all running processes except for with the following Process ID:

• System
• svchost.exe
• csrss.exe
• wininit.exe

It uses the following regular expression to scan track data:

• \d{13,19}=\d{7}\w*\?