BKDR_IRCBOT.UL
Trojan.ADH (Symantec); DoS.Perl.BBDoS.c (Kaspersky); 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.
Installation
This backdoor creates the following folders:
- %System%\logs
- %System%\sounds
(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)
Autostart Technique
This backdoor adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
WinXPService = "%System%\nero.exe"
Other System Modifications
This backdoor deletes the following files:
- %System%\password.val
(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)
It adds the following registry keys:
HKEY_CURRENT_USER\Software\mIRC
HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Uninstall\
mIRC
HKEY_CLASSES_ROOT\.cha
HKEY_CLASSES_ROOT\.chat
HKEY_CLASSES_ROOT\ChatFile
HKEY_CLASSES_ROOT\ChatFile\DefaultIcon
HKEY_CLASSES_ROOT\ChatFile\Shell\
open\command
HKEY_CLASSES_ROOT\ChatFile\Shell\
open\ddeexec
HKEY_CLASSES_ROOT\ChatFile\Shell\
open\ddeexec\Application
HKEY_CLASSES_ROOT\ChatFile\Shell\
open\ddeexec\ifexec
HKEY_CLASSES_ROOT\ChatFile\Shell\
open\ddeexec\Topic
HKEY_LOCAL_MACHINE\Software\Classes\
irc
HKEY_LOCAL_MACHINE\Software\Classes\
irc\DefaultIcon
HKEY_LOCAL_MACHINE\Software\Classes\
irc\Shell\open\
command
HKEY_LOCAL_MACHINE\Software\Classes\
irc\Shell\open\
ddeexec
HKEY_LOCAL_MACHINE\Software\Classes\
irc\Shell\open\
ddeexec\Application
HKEY_LOCAL_MACHINE\Software\Classes\
irc\Shell\open\
ddeexec\ifexec
HKEY_LOCAL_MACHINE\Software\Classes\
irc\Shell\open\
ddeexec\Topic
HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
It adds the following registry entries:
HKEY_CURRENT_USER\Software\mIRC
DateUsed = "1367482722"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
mIRC
DisplayName = "mIRC"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
mIRC
UninstallString = "%System%\nero.exe -uninstall"
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
irc
EditFlags = "{random values}"
HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
VoiceEnabled = "1"
HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
UseVoiceTips = "1"
HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
KeyHoldHotKey = "91"
HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
UseBeepSRPrompt = "1"
HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
SRTimerDelay = "7d"
HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
SRModeID = "{random values}"
HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
EnableSpeaking = "1"
HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
UseBalloon = "1"
HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
UseCharacterFont = "1"
HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
UseSoundEffects = "1"
HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
SpeakingSpeed = "5"
HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
PropertySheetX = "f423f"
HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
PropertySheetY = "f423f"
HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
PropertySheetWidth = "0"
HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
PropertySheetHeight = "0"
HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
PropertySheetPage = "0"
HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
CommandsWindowLeft = "ffffffff"
HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
CommandsWindowTop = "ffffffff"
HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
CommandsWindowWidth = "c8"
HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
CommandsWindowHeight = "c8"
HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
CommandsWindowLocationSet = "0"
Dropping Routine
This backdoor drops the following files:
- %System%\0313.INS
- %System%\86102025.INS
- %System%\27296716.INS
- %System%\31861617.INS
- %System%\37224256.INS
- %System%\8204747.INS
- %System%\7058408.INS
- %System%\5972932.INS
- %System%\91723679.INS
- %System%\77463279.INS
- %System%\69768441.INS
- %System%\71793066.INS
- %System%\16263294.INS
- %System%\46602466.INS
- %System%\82562790.INS
- %System%\48171491.INS
- %System%\87432872.INS
- %System%\77279764.INS
- %System%\49258879.INS
- %System%\8272202.INS
- %System%\14101435.INS
- %System%\5008216.INS
- %System%\592996.INS
- %System%\77446506.INS
- %System%\77047081.INS
- %System%\55752060.INS
- %System%\68105928.INS
- %System%\95546440.INS
- %System%\drivers\oreans32.sys
- %System%\y16.reg
- %System%\TMP1.$$$
- %System%\rdate
- %System%\neroupdate.ini
(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)
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
Restart in Safe Mode
Step 3
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
- mIRC
- In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Uninstall
- mIRC
- In HKEY_CLASSES_ROOT
- .cha
- In HKEY_CLASSES_ROOT
- .chat
- In HKEY_CLASSES_ROOT
- ChatFile
- In HKEY_CLASSES_ROOT\ChatFile
- DefaultIcon
- In HKEY_CLASSES_ROOT\ChatFile\Shell\open
- command
- In HKEY_CLASSES_ROOT\ChatFile\Shell\open
- ddeexec
- In HKEY_CLASSES_ROOT\ChatFile\Shell\open\ddeexec
- Application
- In HKEY_CLASSES_ROOT\ChatFile\Shell\open\ddeexec
- ifexec
- In HKEY_CLASSES_ROOT\ChatFile\Shell\open\ddeexec
- Topic
- In HKEY_LOCAL_MACHINE\Software\Classes
- irc
- In HKEY_LOCAL_MACHINE\Software\Classes\irc
- DefaultIcon
- In HKEY_LOCAL_MACHINE\Software\Classes\irc\Shell\open
- command
- In HKEY_LOCAL_MACHINE\Software\Classes\irc\Shell\open
- ddeexec
- In HKEY_LOCAL_MACHINE\Software\Classes\irc\Shell\open\ddeexec
- Application
- In HKEY_LOCAL_MACHINE\Software\Classes\irc\Shell\open\ddeexec
- ifexec
- In HKEY_LOCAL_MACHINE\Software\Classes\irc\Shell\open\ddeexec
- Topic
- In HKEY_CURRENT_USER\Software\Microsoft
- Microsoft Agent
Step 4
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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- WinXPService = "%System%\nero.exe"
- In HKEY_CURRENT_USER\Software\mIRC
- DateUsed = "1367482722"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\mIRC
- DisplayName = "mIRC"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\mIRC
- UninstallString = "%System%\nero.exe -uninstall"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\irc
- EditFlags = "{random values}"
- In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
- VoiceEnabled = "1"
- In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
- UseVoiceTips = "1"
- In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
- KeyHoldHotKey = "91"
- In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
- UseBeepSRPrompt = "1"
- In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
- SRTimerDelay = "7d"
- In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
- SRModeID = "{random values}"
- In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
- EnableSpeaking = "1"
- In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
- UseBalloon = "1"
- In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
- UseCharacterFont = "1"
- In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
- UseSoundEffects = "1"
- In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
- SpeakingSpeed = "5"
- In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
- PropertySheetX = "f423f"
- In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
- PropertySheetY = "f423f"
- In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
- PropertySheetWidth = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
- PropertySheetHeight = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
- PropertySheetPage = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
- CommandsWindowLeft = "ffffffff"
- In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
- CommandsWindowTop = "ffffffff"
- In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
- CommandsWindowWidth = "c8"
- In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
- CommandsWindowHeight = "c8"
- In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
- CommandsWindowLocationSet = "0"
Step 5
Search and delete these components
- %System%\0313.INS
- %System%\86102025.INS
- %System%\27296716.INS
- %System%\31861617.INS
- %System%\37224256.INS
- %System%\8204747.INS
- %System%\7058408.INS
- %System%\5972932.INS
- %System%\91723679.INS
- %System%\77463279.INS
- %System%\69768441.INS
- %System%\71793066.INS
- %System%\16263294.INS
- %System%\46602466.INS
- %System%\82562790.INS
- %System%\48171491.INS
- %System%\87432872.INS
- %System%\77279764.INS
- %System%\49258879.INS
- %System%\8272202.INS
- %System%\14101435.INS
- %System%\5008216.INS
- %System%\592996.INS
- %System%\77446506.INS
- %System%\77047081.INS
- %System%\55752060.INS
- %System%\68105928.INS
- %System%\95546440.INS
- %System%\drivers\oreans32.sys
- %System%\y16.reg
- %System%\TMP1.$
- %System%\rdate
- %System%\neroupdate.ini
• For Windows Vista and Windows 7 users:
- Click Start>Computer.
- In the Search input box, type:
- %System%\0313.INS
- %System%\86102025.INS
- %System%\27296716.INS
- %System%\31861617.INS
- %System%\37224256.INS
- %System%\8204747.INS
- %System%\7058408.INS
- %System%\5972932.INS
- %System%\91723679.INS
- %System%\77463279.INS
- %System%\69768441.INS
- %System%\71793066.INS
- %System%\16263294.INS
- %System%\46602466.INS
- %System%\82562790.INS
- %System%\48171491.INS
- %System%\87432872.INS
- %System%\77279764.INS
- %System%\49258879.INS
- %System%\8272202.INS
- %System%\14101435.INS
- %System%\5008216.INS
- %System%\592996.INS
- %System%\77446506.INS
- %System%\77047081.INS
- %System%\55752060.INS
- %System%\68105928.INS
- %System%\95546440.INS
- %System%\drivers\oreans32.sys
- %System%\y16.reg
- %System%\TMP1.$
- %System%\rdate
- %System%\neroupdate.ini
- Once located, select the file then press SHIFT+DELETE to delete it.
- Repeat the said steps for all files listed.
*Note: Read the following Microsoft page if these steps do not work on Windows 7.
Step 6
Search and delete these folders
- %System%\logs
- %System%\sounds
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_IRCBOT.UL. 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 8
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.
- %System%\password.val
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