TROJ_DROPPER.QCZ
Worm:Win32/Slenfbot.AIM (Microsoft); W32/Hamweq.worm.n (McAfee); W32.Rixobot (Symantec); Backdoor.Win32.IRCBot.nhk (Kaspersky); Worm.Win32.Palevo.nfn (v) (Sunbelt); Trojan.Downloader.JMPD (FSecure)
Windows 2000, Windows XP, Windows Server 2003
![](/vinfo/imgFiles/legend.jpg)
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
159,744 bytes
EXE
Yes
25 Sep 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 drops the following copies of itself into the affected system:
- %System%\wmirpce.exe
(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)
Autostart Technique
This Trojan adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
ctfmon.exe = "ctfmon.exe"
Other System Modifications
This Trojan deletes the following files:
- %System%\wmirpce.exe
(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)
It adds the following registry keys:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\AppCompatFlags\
Layers
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
ctfmon.exe
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%System%\wmirpce.exe = "%System%\wmirpce.exe:*:Enabled:UPnP Firewall"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\DomainProfile\AuthorizedApplications\
List
%System%\wmirpce.exe = "%System%\wmirpce.exe:*:Enabled:UPnP Firewall"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\SafeBoot\Minimal
ctfmon.exe = "ctfmon.exe"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\SafeBoot\Network
ctfmon.exe = "ctfmon.exe"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
ctfmon.exe
Debugger = "wmirpce.exe"
Dropping Routine
This Trojan drops the following files:
- %System%\drivers\kernelx86.sys
(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)
This report is generated via an automated analysis system.
SOLUTION
9.200
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
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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AppCompatFlags
- Layers
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options
- ctfmon.exe
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
- ctfmon.exe = "ctfmon.exe"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
- %System%\wmirpce.exe = "%System%\wmirpce.exe:*:Enabled:UPnP Firewall"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\DomainProfile\AuthorizedApplications\List
- %System%\wmirpce.exe = "%System%\wmirpce.exe:*:Enabled:UPnP Firewall"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\SafeBoot\Minimal
- ctfmon.exe = "ctfmon.exe"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\SafeBoot\Network
- ctfmon.exe = "ctfmon.exe"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\ctfmon.exe
- Debugger = "wmirpce.exe"
Step 5
Search and delete this file
- %System%\drivers\kernelx86.sys
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_DROPPER.QCZ. 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.
- %System%\wmirpce.exe
Did this description help? Tell us how we did.