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TROJ_KRYPTIK.YYN

May 19, 2014
 ALIASES:

Trojan.Smoaler (Symantec); HEUR:Trojan.Win32.Generic (Kaspersky); Troj/Agent-AGXX (Sophos); Trojan.Win32.Generic!BT (Sunbelt)

 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:

  • 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 deletes itself after execution.

  TECHNICAL DETAILS

File Size:

223,744 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

19 May 2014

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.

Dropping Routine

This Trojan drops the following files:

  • %User Temp%\persist.vbs
  • %Windows%\Fonts\cpuret.fon
  • %Windows%\Tasks\Microsoft Office Fetcher.job
  • %User Profile%\History.IE5\index.dbt
  • %Application Data%\Microsoft\Internet Explorer\MSIMGSIY.DAT
  • %User Profile%\Internet Explorer\brndlog.tyt
  • %Application Data%\Microsoft\Internet Explorer\MSIMGTIZ.DAT
  • %User Profile%\MMC\tecpol

(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.. %Windows% is the Windows folder, which is usually C:\Windows.. %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.. %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)

Other Details

This Trojan deletes itself after execution.

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.700

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

Search and delete these components

[ Learn More ]
There may be some components 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 Temp%\persist.vbs
  • %Windows%\Fonts\cpuret.fon
  • %Windows%\Tasks\Microsoft Office Fetcher.job
  • %User Profile%\History.IE5\index.dbt
  • %Application Data%\Microsoft\Internet Explorer\MSIMGSIY.DAT
  • %User Profile%\Internet Explorer\brndlog.tyt
  • %Application Data%\Microsoft\Internet Explorer\MSIMGTIZ.DAT
  • %User Profile%\MMC\tecpol

Step 3

Scan your computer with your Trend Micro product to delete files detected as TROJ_KRYPTIK.YYN. 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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