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