TSPY_TINECUF.ANB

 Analysis by: Rika Joi Gregorio

 ALIASES:

TrojanDownloader:Win32/Injector.gen!W(Microsoft), Win32/TrojanDownloader.Agent.NKE trojan(Eset), Downloader(Symantec)

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • Threat Type: Spyware

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Dropped by other malware, Downloaded from the Internet

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.

It does not have any propagation routine.

It does not have any backdoor routine.

It executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system. As of this writing, the said sites are inaccessible.

It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size:

10,317 bytes

File Type:

EXE, DLL

Memory Resident:

Yes

Initial Samples Received Date:

07 Feb 2014

Payload:

Downloads files

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 component file(s):

  • %Windows%\Downloaded Program Files\ZipExt32.dll - also detected as TSPY_TINECUF.ANB

(Note: %Windows% is the Windows folder, which is usually C:\Windows.)

It drops and executes the following files:

  • %User Temp%\7ztmp.bat - used to delete itself

(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, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

It drops the following non-malicious file:

  • %System Root%\tmp.hiv - will be deleted afterwards

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

Its DLL component is injected to the following process(es):

  • explorer.exe

Autostart Technique

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

HKEY_CLASSES_ROOT\CLSID\{35CEC8A3-2BE6-11D2-8773-92E220524140}\
InProcServer32
(Default) = "%Windows%\Downloaded Program Files\ZipExt32.dll"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\ShellServiceObjectDelayLoad
ZipExt32 = "{35CEC8A3-2BE6-11D2-8773-92E220524140}"

Other System Modifications

This spyware adds the following registry keys:

HKEY_CLASSES_ROOT\CLSID\{35CEC8A3-2BE6-11D2-8773-92E220524140}

HKEY_CLASSES_ROOT\CLSID\{35CEC8A3-2BE6-11D2-8773-92E220524140}\
InProcServer32

It adds the following registry entries:

HKEY_CLASSES_ROOT\CLSID\{35CEC8A3-2BE6-11D2-8773-92E220524140}
(Default) = "ZipExt32"

HKEY_CLASSES_ROOT\CLSID\{35CEC8A3-2BE6-11D2-8773-92E220524140}\
InProcServer32
ThreadingModel = "Both"

Propagation

This spyware does not have any propagation routine.

Backdoor Routine

This spyware does not have any backdoor routine.

Download Routine

This spyware accesses the following websites to download files:

  • http://www.{BLOCKED}63.com/mm/cfg2.txt
  • http://ww{BLOCKED}8.{BLOCKED}3.com/mm/cfg2.txt
  • http://www.{BLOCKED}63.com/u319.exe
  • http://mm.{BLOCKED}63.com/u319.exe

It saves the files it downloads using the following names:

  • %System Root%\z.ini
  • %User Temp%\wsctny1.exe
  • %User Temp%\wsctny2.exe

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

It then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

As of this writing, the said sites are inaccessible.

Information Theft

This spyware gathers the following data:

  • OS Version
  • Computer Name

Stolen Information

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

  • http://www.{BLOCKED}63.com/mm/dg1/log.asp?isnew=-1&LocalInfo={OS Version}&szHostName={Computer Name}&tmp3=tmp3
  • http://ww38.{BLOCKED}63.com/mm/dg1/log.asp?isnew=-1&LocalInfo={OS Version}&szHostName={Computer Name}&tmp3=tmp3

Other Details

This spyware deletes the initially executed copy of itself

NOTES:

If %Windows%\Downloaded Program Files\ZipExt32.dll already exists, it will rename %Windows%\Downloaded Program Files\ZipExt32.dll to %Windows%\Downloaded Program Files\Ext32.dat. Before the malware does this, it deletes the file %Windows%\Downloaded Program Files\Ext32.dat first.

It drops and executes the file %System Root%\sysret.dat (detected as RTKT_RETYS.ANB) if avp.exe is currently running on the system.

It deletes the files %System Root%\z.ini and cfg.txt from the cache before performing its download routine.

If the files %User Temp%\wsctny1.exe and %User Temp%\wsctny2.exe already exist, it renames the file %User Temp%\wsctny1.exe to %User Temp%\wsctny1.tmp and %User Temp%\wsctny2.exe to %User Temp%\wsctny1.tmp~ first before performing its download routine.

It deletes the downloaded files %User Temp%\wsctny1.exe and %User Temp%\wsctny2.exe after executing it.

It does not have rootkit capabilities.

It does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine:

9.700

FIRST VSAPI PATTERN FILE:

10.596.05

FIRST VSAPI PATTERN DATE:

09 Feb 2014

VSAPI OPR PATTERN File:

10.597.00

VSAPI OPR PATTERN Date:

10 Feb 2014

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

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Remove malware/grayware files dropped/downloaded by TSPY_TINECUF.ANB. (Note: Please skip this step if the threats listed below have already been removed.)

  • RTKT_RETYS.ANB

Step 4

Restart in Safe Mode

[ Learn More ]

Step 5

Delete this registry key

[ Learn More ]

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_CLASSES_ROOT\CLSID
    • {35CEC8A3-2BE6-11D2-8773-92E220524140}

Step 6

Delete this registry value

[ Learn More ]

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\ShellServiceObjectDelayLoad
    • ZipExt32 = "{35CEC8A3-2BE6-11D2-8773-92E220524140}"

Step 7

Search and delete these files

[ Learn More ]
There may be some component 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.
  • %System Root%\z.ini
  • %User Temp%\wsctny1.exe
  • %User Temp%\wsctny2.exe
  • %User Temp%\wsctny1.tmp
  • %User Temp%\wsctny1.tmp~
  • %System Root%\tmp.hiv
  • %User Temp%\7ztmp.bat

Step 8

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TSPY_TINECUF.ANB. 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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