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TROJ_SMALL.GEY

October 13, 2012
 ALIASES:

TrojanDropper:Win32/Small (Microsoft); [0006773c.EXE]:Generic BackDoor (McAfee); Infostealer (Symantec); PAK:UPack, Trojan-Dropper.Win32.Small.axi (Kaspersky); BehavesLike.Win32.Malware.bsf (vs) (Sunbelt); Trojan.Generic.6312366 (FSecure)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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 modifies files, disabling programs and applications from properly running.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size:

270,336 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

24 Jun 2012

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.

Other System Modifications

This Trojan modifies the following files:

  • %System%\npptools.dll

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

Dropping Routine

This Trojan drops the following files:

  • %System%\Packet.dll
  • %System%\wpcap.dll
  • %System%\WanPacket.dll
  • %System%\drivers\npf.sys
  • %System%\nslookupi.exe
  • %System Root%\$$a.bat

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.. %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

Other Details

This Trojan deletes itself after execution.

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.200

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

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%\Packet.dll
  • %System%\wpcap.dll
  • %System%\WanPacket.dll
  • %System%\drivers\npf.sys
  • %System%\nslookupi.exe
  • %System Root%\a.bat
a.bat
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 3

    Scan your computer with your Trend Micro product to delete files detected as TROJ_SMALL.GEY. 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.

    Step 4

    Restore deleted/modified files and/or registry entries from backup

    *Note: Only Microsoft-related files/keys/values will be restored. If this malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.

      • %System%\npptools.dll


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