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
It terminates running processes that have the following file extensions:
- .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:
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
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To restart in Safe Mode:
• For Windows 2000 users
- Restart your computer.
- Press F8 when you see the Starting Windows bar at the bottom of the screen.
- Choose the Safe Mode option from the Windows Advanced Options menu then press Enter.
• For Windows XP users
- Restart your computer.
- Press F8 after the Power-On Self Test (POST) routine is done. If the Windows Advanced Options menu does not appear, try restarting then pressing F8 several times when the POST screen appears.
- Choose the Safe Mode option from the Windows Advanced Options menu then press Enter.
• For Windows Server 2003 users
- Restart your computer.
- Press F8 after Windows starts up. If the Windows Advanced Options menu does not appear, try restarting again and pressing F8 several times afterward.
- On the Windows Advanced Option menu, use the arrow keys to select Safe Mode then press Enter.
• For Windows Vista and Windows 7 users
- Restart your computer.
- Press F8 after the Power-On Self Test (POST) routine is done. If the Advanced Boot Options menu does not appear, try restarting and then pressing F8 several times after the POST screen is displayed.
- On the Advanced Boot Options menu, use the arrow keys to select the Safe Mode option, and then press Enter.
Step 3
Delete this registry value
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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
- 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
- In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows
- Load = "%User Profile%\InternetExplorer.lnk" - If OS version is Windows Vista and up
To delete the registry value this malware created:
- Open Registry Editor. To do this, click Start>Run, type regedit in the text box provided, then press Enter.
- In the left panel of the Registry Editor window, double-click the following:
HKEY_CURRENT_USER>Software>Microsoft>Windows>CurrentVersion>Policies>Explorer>Run - In the right panel, locate and delete the entry:
Internet Explorer = "%User Profile%\InternetExplorer.lnk" - If OS version is lower than Windows Vista - In the left panel of the Registry Editor window, double-click the following:
HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Windows>CurrentVersion>policies>Explorer>Run - In the right panel, locate and delete the entry:
Internet Explorer = "%User Profile%\InternetExplorer.lnk" - If OS version is lower than Windows Vista - In the left panel of the Registry Editor window, double-click the following:
HKEY_CURRENT_USER>Software>Microsoft>Windows NT>CurrentVersion>Windows - In the right panel, locate and delete the entry:
Load = "%User Profile%\InternetExplorer.lnk" - If OS version is Windows Vista and up - Close Registry Editor.
Step 4
Search and delete these files
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There may be some files that are hidden. Please make sure you check the
Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
- %User Profile%\InternetExplorer.lnk
- %User Profile%\{hex values derived from username}.dat
- %User Profile%\{hex values derived from computer name}.dat
To delete malware/grayware files:
- Search for the following files:
- %User Profile%\InternetExplorer.lnk
- %User Profile%\{hex values derived from username}.dat
- %User Profile%\{hex values derived from computer name}.dat
Note: To do a search for the following files, right-click Start then click Search... or Find..., depending on the version of Windows you are running. For each file to be deleted, type its file name in the Named input box. In the Look In drop-down list, select My Computer, then press Enter. - Once located, select the file then press SHIFT+DELETE to permanently delete the file.
- Repeat the said steps for all files listed.
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.
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