BKDR_BLOHI.AV
Trojan.ADH.2 (Symantec); Trojan.Win32.Generic!BT (Sunbelt)
Windows 2000, Windows XP, Windows Server 2003
Threat Type: Backdoor
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This backdoor 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
Arrival Details
This backdoor 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 backdoor deletes the following files:
- %User Temp%\nsg1.tmp
- %System Root%\Addresses.TMP
- %System Root%\Memory.TMP
(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.. %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)
It adds the following registry keys:
HKEY_CURRENT_USER\Software\Apple Engine
It adds the following registry entries:
HKEY_CURRENT_USER\Software\Apple Engine
Undo = "1"
HKEY_CURRENT_USER\Software\Apple Engine
Advanced = "1"
HKEY_CURRENT_USER\Software\Apple Engine
SeperateThread = "1"
HKEY_CURRENT_USER\Software\Apple Engine
Use hy_perscan if posible = "0"
HKEY_CURRENT_USER\Software\Apple Engine
ScanThreadpriority = "4"
HKEY_CURRENT_USER\Software\Apple Engine
First Time User = "0"
Dropping Routine
This backdoor drops the following files:
- \Server.exe
- \Apple Engine.exe
- %System Root%\accesscheck.tmp
(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)
Other Details
This backdoor connects to the following possibly malicious URL:
- http://heck.{BLOCKED}y.com/attachment/cfile25.uf@116C5C47504ACDCD0BB83F.dll
- http://heck.{BLOCKED}y.com/attachment/cfile30.uf@136B2E47504ACDCE0E1852.dll
- http://heck.{BLOCKED}y.com/attachment/cfile27.uf@13717847504ACDCE05A0DB.dll
- http://heck.{BLOCKED}y.com/attachment/cfile21.uf@144CD247504ACDCE2FD850.OCX
- http://heck.{BLOCKED}y.com/attachment/cfile10.uf@1470E447504ACDCF06599B.OCX
- http://heck.{BLOCKED}y.com/attachment/cfile25.uf@2071CE47504ACDD205F28A.OCX
This report is generated via an automated analysis system.
SOLUTION
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
Delete this registry key
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
- Apple Engine
Step 3
Delete this registry value
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\Apple Engine
- Undo = "1"
- In HKEY_CURRENT_USER\Software\Apple Engine
- Advanced = "1"
- In HKEY_CURRENT_USER\Software\Apple Engine
- SeperateThread = "1"
- In HKEY_CURRENT_USER\Software\Apple Engine
- Use hy_perscan if posible = "0"
- In HKEY_CURRENT_USER\Software\Apple Engine
- ScanThreadpriority = "4"
- In HKEY_CURRENT_USER\Software\Apple Engine
- First Time User = "0"
Step 4
Search and delete these files
- \Server.exe
- \Apple Engine.exe
- %System Root%\accesscheck.tmp
Step 5
Scan your computer with your Trend Micro product to delete files detected as BKDR_BLOHI.AV. 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 6
Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.
- %User Temp%\nsg1.tmp
- %System Root%\Addresses.TMP
- %System Root%\Memory.TMP
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