BKDR_IRCBOT.EJB
Trojan horse Downloader.MSIL.LA (AVG)
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: 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.
Installation
This backdoor creates the following folders:
- %System Root%\Documents and Settings\Wilbert
- %User Profile%\Microsoft\CLR Security Config
- %User Profile%\CLR Security Config\v2.0.50727.42
- %User Profile%\Application Data\dclogs
(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %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.)
Other System Modifications
This backdoor deletes the following files:
- {malware path and file name}:zone.identifier
- %User Profile%\Templates\dwm.exe:Zone.Identifier
- Desktop:Zone.Identifier
- %User Temp%\cmiadapter.exe:Zone.Identifier
- %User Temp%\PrintConfig.exe:Zone.Identifier
(Note: %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.. %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.)
It adds the following registry keys:
HKEY_CURRENT_USER\Software\DC3_FEXEC
It adds the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Winlogon
Shell = "%Windows%\explorer.exe, %User Temp%\cmiadapter.exe"
HKEY_CURRENT_USER\Software\DC3_FEXEC
7/21/2014 at 3:18:07 PM = "{1c6961c0-f82d-11e0-a6bd-806d6172696f-1756172240}"
Dropping Routine
This backdoor drops the following files:
- %Windows%\Microsoft.NET\Framework\v2.0.50727\config\security.config.cch.new
- %User Profile%\v2.0.50727.42\security.config.cch.new
- %Windows%\Microsoft.NET\Framework\v2.0.50727\config\enterprisesec.config.cch.new
- %Desktop%\form.txt
- %User Temp%\cmiadapter.exe
- %User Temp%\PrintConfig.exe
(Note: %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.. %Desktop% is the current user's desktop, which is usually C:\Documents and Settings\{User Name}\Desktop on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\Desktop on Windows Vista and 7.. %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.)
Other Details
This backdoor connects to the following possibly malicious URL:
- {BLOCKED}.99.118
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
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
- DC3_FEXEC
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\Microsoft\Windows NT\CurrentVersion\Winlogon
- Shell = "%Windows%\explorer.exe, %User Temp%\cmiadapter.exe"
- In HKEY_CURRENT_USER\Software\DC3_FEXEC
- 7/21/2014 at 3:18:07 PM = "{1c6961c0-f82d-11e0-a6bd-806d6172696f-1756172240}"
Step 4
Search and delete these components
- %Windows%\Microsoft.NET\Framework\v2.0.50727\config\security.config.cch.new
- %User Profile%\v2.0.50727.42\security.config.cch.new
- %Windows%\Microsoft.NET\Framework\v2.0.50727\config\enterprisesec.config.cch.new
- %Desktop%\form.txt
- %User Temp%\cmiadapter.exe
- %User Temp%\PrintConfig.exe
Step 5
Search and delete these folders
- %System Root%\Documents and Settings\Wilbert
- %User Profile%\Microsoft\CLR Security Config
- %User Profile%\CLR Security Config\v2.0.50727.42
- %User Profile%\Application Data\dclogs
Step 6
Scan your computer with your Trend Micro product to delete files detected as BKDR_IRCBOT.EJB. 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 7
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.
- {malware path and file name}:zone.identifier
- %User Profile%\Templates\dwm.exe:Zone.Identifier
- Desktop:Zone.Identifier
- %User Temp%\cmiadapter.exe:Zone.Identifier
- %User Temp%\PrintConfig.exe:Zone.Identifier
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