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TROJ_BOLTOLOG.AZ

February 12, 2013
 ALIASES:

TrojanDropper:Win32/Vundo.H (Microsoft); Vundo.gen.av (McAfee); Packed.Generic.202 (Symantec); Trojan.Crypt.Krap (v) (Sunbelt); Win32/Heur (AVG)

 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 deletes itself after execution.

  TECHNICAL DETAILS

File Size:

53,760 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

12 Feb 2013

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 adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Control Panel\
Settings

HKEY_CLASSES_ROOT\CLSID\{6D794CB4-C7CD-4c6f-BFDC-9B77AFBDC02C}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{6D794CB4-C7CD-4c6f-BFDC-9B77AFBDC02C}\InprocServer32

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\awtqnkhe

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Control Panel\
Settings
Time = "{random values}"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{6D794CB4-C7CD-4c6f-BFDC-9B77AFBDC02C}\InprocServer32
ThreadingModel = "Both"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\awtqnkhe
Asynchronous = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\awtqnkhe
DllName = "awtqnkhe.dll"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\awtqnkhe
Impersonate = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\awtqnkhe
Logon = "o"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\awtqnkhe
Logoff = "f"

Dropping Routine

This Trojan drops the following files:

  • %System%\awtqnkhe.dll

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

Other Details

This Trojan deletes itself after execution.

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.300

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Control Panel
    • Settings
  • In HKEY_CLASSES_ROOT\CLSID
    • {6D794CB4-C7CD-4c6f-BFDC-9B77AFBDC02C}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{6D794CB4-C7CD-4c6f-BFDC-9B77AFBDC02C}
    • InprocServer32
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify
    • awtqnkhe

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Control Panel\Settings
    • Time = "{random values}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{6D794CB4-C7CD-4c6f-BFDC-9B77AFBDC02C}\InprocServer32
    • ThreadingModel = "Both"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\awtqnkhe
    • Asynchronous = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\awtqnkhe
    • DllName = "awtqnkhe.dll"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\awtqnkhe
    • Impersonate = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\awtqnkhe
    • Logon = "o"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\awtqnkhe
    • Logoff = "f"

Step 4

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.
  • %System%\awtqnkhe.dll

Step 5

Scan your computer with your Trend Micro product to delete files detected as TROJ_BOLTOLOG.AZ. 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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