TSPY_DECBAL.A
Win32/Spy.POSCardStealer.U trojan (NOD32)
Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)
Threat Type: Spyware
Destructiveness: No
Encrypted: No
In the wild: Yes
OVERVIEW
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.
TECHNICAL DETAILS
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*\?
SOLUTION
Step 1
Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.
Step 2
Restart in Safe Mode
Step 3
Delete this registry value
Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\Run
- Internet Explorer = "%User Profile%\InternetExplorer.lnk" - If OS version is lower than Windows Vista
- Internet Explorer = "%User Profile%\InternetExplorer.lnk" - If OS version is lower than Windows Vista
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer\Run
- Internet Explorer = "%User Profile%\InternetExplorer.lnk" - If OS version is lower than Windows Vista
- Internet Explorer = "%User Profile%\InternetExplorer.lnk" - If OS version is lower than Windows Vista
- In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows
- Load = "%User Profile%\InternetExplorer.lnk" - If OS version is Windows Vista and up
- Load = "%User Profile%\InternetExplorer.lnk" - If OS version is Windows Vista and up
Step 4
Search and delete these files
- %User Profile%\InternetExplorer.lnk
- %User Profile%\{hex values derived from username}.dat
- %User Profile%\{hex values derived from computer name}.dat
Step 5
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TSPY_DECBAL.A. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.
Did this description help? Tell us how we did.