TROJ_BLYAME.SMEP


 ALIASES:

Trojan:Win32/Bamital.E (Microsoft); BackDoor-DKI.gen.bx (McAfee); Trojan.Bamital (Symantec); Trojan-Dropper.Win32.Drooptroop.aam (Kaspersky); Trojan.Win32.Bamital.G (v) (Sunbelt); Trojan.Dropper.Agent.UWS (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.

  TECHNICAL DETAILS

File Size:

35,840 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

10 May 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.

Installation

This Trojan creates the following folders:

  • %Application Data%\Windows Server

(Note: %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 System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\zkblyklrkg

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Session Manager\AppCertDlls

It adds the following registry entries:

HKEY_CURRENT_USER\Software\zkblyklrkg
zkblyklrkg = "{random values}"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\Session Manager\AppCertDlls
AppSecDll = "%Application Data%\Windows Server\yklrkg.dll"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\sr\Parameters
FirstRun = "1"

Dropping Routine

This Trojan drops the following files:

  • %Application Data%\Windows Server\yklrkg.dll

(Note: %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.)

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.200

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

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_CURRENT_USER\Software
    • zkblyklrkg
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager
    • AppCertDlls

Step 3

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_CURRENT_USER\Software\zkblyklrkg
    • zkblyklrkg = "{random values}"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Session Manager\AppCertDlls
    • AppSecDll = "%Application Data%\Windows Server\yklrkg.dll"

Step 4

Restore these modified registry values

[ Learn More ]

Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\sr\Parameters
    • FirstRun = "1"

Step 5

Search and delete this file

[ Learn More ]
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.
  • %Application Data%\Windows Server\yklrkg.dll

Step 6

Search and delete this folder

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %Application Data%\Windows Server

Step 7

Scan your computer with your Trend Micro product to delete files detected as TROJ_BLYAME.SMEP. 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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