This file infector infects by appending its code to target host files.
It drops copies of itself in all removable drives. It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.
However, as of this writing, the said sites are inaccessible.
It deletes itself after execution.
Other System Modifications
This file infector deletes the following registry keys:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AppMgmt
File Infection
This file infector infects the following file types:
It infects by appending its code to target host files.
Propagation
This file infector drops copies of itself in all removable drives.
It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.
The said .INF file contains the following strings:
[autorun]
OPEN=recycle.{645FF040-5081-101B-9F08-00AA002F954E}\uninstall.exe
shell\open=´ò¿ª(&O)
shell\open\Command=recycle.{645FF040-5081-101B-9F08-00AA002F954E}\uninstall.exe Show
shell\open\Default=1//
shell\explore=×ÊÔ´¹ÜÀíÆ÷(&X)
shell\explore\Command=recycle.{645FF040-5081-101B-9F08-00AA002F954E}\uninstall.exe Show
Backdoor Routine
However, as of this writing, the said sites are inaccessible.
Dropping Routine
This file infector drops the following files:
- %System%\dmutilio.dll - detected as TROJ_HORST.JY
(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.)
Other Details
This file infector attempts to access the following websites to download files, which are possibly malicious:
- http://{BLOCKED}85.199/cl/28.exe
- http://{BLOCKED}8.245.140/msdownload/update/v5/redir/wuredirt.rar
- http://{BLOCKED}mvps.org/resources/tools/getpublicip.shtml
It does the following:
- It creates a registry entry for certain application names located under the following key:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options
The created entry contains the following data value: Debugger = "ntsd-d " - Affected application keys are as follows:
360SoftMgrSvc.exe
360hotfix.exe
360rp.exe
360rpt.exe
360safe.exe
360safebox.exe
360sd.exe
360se.exe
360speedld.exe
360tray.exe
AvastUI.exe
CCenter.exe
FilMsg.exe
KVMonXP.exe
KVMonXP.kxp
KVSrvXP.exe
MPMon.exe
MPSVC.exe
MPSVC1.exe
MPSVC2.exe
McNASvc.exe
McProxy.exe
McSACore.exe
Mcagent.exe
Mcods.exe
Mcshield.exe
MpfSrv.exe
RavMonD.exe
RavTask.exe
RsAgent.exe
RsTray.exe
ScanFrm.exe
SfCtlCom.exe
SpIDerMl.exe
TMBMSRV.exe
TmProxy.exe
Twister.exe
UfSeAgnt.exe
afwServ.exe
ast.exe
avcenter.exe
avfwsvc.exe
avgnt.exe
avguard.exe
avmailc.exe
avp.exe
avshadow.exe
avwebgrd.exe
bdagent.exe
ccSvcHst.exe
dwengine.exe
egui.exe
ekrn.exe
kavstart.exe
kissvc.exe
kmailmon.exe
kpfw32.exe
kpfwsvc.exe
kpopserver.exe
krnl360svc.exe
ksmgui.exe
ksmsvc.exe
kswebshield.exe
kwatch.exe
kwstray.exe
kxedefend.exe
kxesapp.exe
kxescore.exe
kxeserv.exe
kxetray.exe
livesrv.exe
mcmscsvc.exe
mcsysmon.exe
mcvsshld.exe
msksrver.exe
qutmserv.exe
rsnetsvr.exe
safeboxTray.exe
sched.exe
seccenter.exe
spideragent.exe
spidernt.exe
spiderui.exe
vsserv.exe
zhudongfangyu.exe
ÐÞ¸´¹¤¾ß.exe - It overwrites the following file with a copy of itself: %System%\appmgmts.dll
(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 deletes itself after execution.
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
Remove malware files dropped/downloaded by PE_NIMNUL.A-O
Step 3
Restart in Safe Mode
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To restart in Safe Mode:
• For Windows 2000 users
- Restart your computer.
- Press F8 when you see the Starting Windows bar at the bottom of the screen.
- Choose the Safe Mode option from the Windows Advanced Options menu then press Enter.
• For Windows XP users
- Restart your computer.
- Press F8 after the Power-On Self Test (POST) routine is done. If the Windows Advanced Options menu does not appear, try restarting then pressing F8 several times when the POST screen appears.
- Choose the Safe Mode option from the Windows Advanced Options menu then press Enter.
• For Windows Server 2003 users
- Restart your computer.
- Press F8 after Windows starts up. If the Windows Advanced Options menu does not appear, try restarting again and pressing F8 several times afterward.
- On the Windows Advanced Option menu, use the arrow keys to select Safe Mode then press Enter.
Step 4
Delete this registry key
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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.
(Note: Delete the key only if the value Debugger = ntsd-d is added.)
In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\- Image File Execution Options
In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ To delete the registry key this malware/grayware created:
- Open Registry Editor. Click Start>Run, type REGEDIT, then press Enter.
- In the left panel, double-click the following:
HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Windows NT>CurrentVersion> - Still in the left panel, locate and delete the key:
Image File Execution Options - Again Still in the left panel, locate and delete the key:
360SoftMgrSvc.exe - Again Still in the left panel, locate and delete the key:
360hotfix.exe - Again Still in the left panel, locate and delete the key:
360rp.exe - Again Still in the left panel, locate and delete the key:
360rpt.exe - Again Still in the left panel, locate and delete the key:
360safe.exe - Again Still in the left panel, locate and delete the key:
360safebox.exe - Again Still in the left panel, locate and delete the key:
360sd.exe - Again Still in the left panel, locate and delete the key:
360se.exe - Again Still in the left panel, locate and delete the key:
360speedld.exe - Again Still in the left panel, locate and delete the key:
360tray.exe - Again Still in the left panel, locate and delete the key:
AvastUI.exe - Again Still in the left panel, locate and delete the key:
CCenter.exe - Again Still in the left panel, locate and delete the key:
FilMsg.exe - Again Still in the left panel, locate and delete the key:
KVMonXP.exe - Again Still in the left panel, locate and delete the key:
KVMonXP.kxp - Again Still in the left panel, locate and delete the key:
KVSrvXP.exe - Again Still in the left panel, locate and delete the key:
MPMon.exe - Again Still in the left panel, locate and delete the key:
MPSVC.exe - Again Still in the left panel, locate and delete the key:
MPSVC1.exe - Again Still in the left panel, locate and delete the key:
MPSVC2.exe - Again Still in the left panel, locate and delete the key:
McNASvc.exe - Again Still in the left panel, locate and delete the key:
McProxy.exe - Again Still in the left panel, locate and delete the key:
McSACore.exe - Again Still in the left panel, locate and delete the key:
Mcagent.exe - Again Still in the left panel, locate and delete the key:
Mcods.exe - Again Still in the left panel, locate and delete the key:
Mcshield.exe - Again Still in the left panel, locate and delete the key:
MpfSrv.exe - Again Still in the left panel, locate and delete the key:
RavMonD.exe - Again Still in the left panel, locate and delete the key:
RavTask.exe - Again Still in the left panel, locate and delete the key:
RsAgent.exe - Again Still in the left panel, locate and delete the key:
RsTray.exe - Again Still in the left panel, locate and delete the key:
ScanFrm.exe - Again Still in the left panel, locate and delete the key:
SfCtlCom.exe - Again Still in the left panel, locate and delete the key:
SpIDerMl.exe - Again Still in the left panel, locate and delete the key:
TMBMSRV.exe - Again Still in the left panel, locate and delete the key:
TmProxy.exe - Again Still in the left panel, locate and delete the key:
Twister.exe - Again Still in the left panel, locate and delete the key:
UfSeAgnt.exe - Again Still in the left panel, locate and delete the key:
afwServ.exe - Again Still in the left panel, locate and delete the key:
ast.exe - Again Still in the left panel, locate and delete the key:
avcenter.exe - Again Still in the left panel, locate and delete the key:
avfwsvc.exe - Again Still in the left panel, locate and delete the key:
avgnt.exe - Again Still in the left panel, locate and delete the key:
avguard.exe - Again Still in the left panel, locate and delete the key:
avmailc.exe - Again Still in the left panel, locate and delete the key:
avp.exe - Again Still in the left panel, locate and delete the key:
avshadow.exe - Again Still in the left panel, locate and delete the key:
avwebgrd.exe - Again Still in the left panel, locate and delete the key:
bdagent.exe - Again Still in the left panel, locate and delete the key:
ccSvcHst.exe - Again Still in the left panel, locate and delete the key:
dwengine.exe - Again Still in the left panel, locate and delete the key:
egui.exe - Again Still in the left panel, locate and delete the key:
ekrn.exe - Again Still in the left panel, locate and delete the key:
kavstart.exe - Again Still in the left panel, locate and delete the key:
kissvc.exe - Again Still in the left panel, locate and delete the key:
kmailmon.exe - Again Still in the left panel, locate and delete the key:
kpfw32.exe - Again Still in the left panel, locate and delete the key:
kpfwsvc.exe - Again Still in the left panel, locate and delete the key:
kpopserver.exe - Again Still in the left panel, locate and delete the key:
krnl360svc.exe - Again Still in the left panel, locate and delete the key:
ksmgui.exe - Again Still in the left panel, locate and delete the key:
ksmsvc.exe - Again Still in the left panel, locate and delete the key:
kswebshield.exe - Again Still in the left panel, locate and delete the key:
kwatch.exe - Again Still in the left panel, locate and delete the key:
kwstray.exe - Again Still in the left panel, locate and delete the key:
kxedefend.exe - Again Still in the left panel, locate and delete the key:
kxesapp.exe - Again Still in the left panel, locate and delete the key:
kxescore.exe - Again Still in the left panel, locate and delete the key:
kxeserv.exe - Again Still in the left panel, locate and delete the key:
kxetray.exe - Again Still in the left panel, locate and delete the key:
livesrv.exe - Again Still in the left panel, locate and delete the key:
mcmscsvc.exe - Again Still in the left panel, locate and delete the key:
mcsysmon.exe - Again Still in the left panel, locate and delete the key:
mcvsshld.exe - Again Still in the left panel, locate and delete the key:
msksrver.exe - Again Still in the left panel, locate and delete the key:
qutmserv.exe - Again Still in the left panel, locate and delete the key:
rsnetsvr.exe - Again Still in the left panel, locate and delete the key:
safeboxTray.exe - Again Still in the left panel, locate and delete the key:
sched.exe - Again Still in the left panel, locate and delete the key:
seccenter.exe - Again Still in the left panel, locate and delete the key:
spideragent.exe - Again Still in the left panel, locate and delete the key:
spidernt.exe - Again Still in the left panel, locate and delete the key:
spiderui.exe - Again Still in the left panel, locate and delete the key:
vsserv.exe - Again Still in the left panel, locate and delete the key:
zhudongfangyu.exe - Again Still in the left panel, locate and delete the key:
ÐÞ¸´¹¤¾ß.exe - Close Registry Editor.
Step 5
Search and delete AUTORUN.INF files created by PE_NIMNUL.A-O that contain these strings
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[autorun]OPEN=recycle.{645FF040-5081-101B-9F08-00AA002F954E}\uninstall.exe
shell\open=´ò¿ª(&O)
shell\open\Command=recycle.{645FF040-5081-101B-9F08-00AA002F954E}\uninstall.exe Show
shell\open\Default=1//
shell\explore=×ÊÔ´¹ÜÀíÆ÷(&X)
shell\explore\Command=recycle.{645FF040-5081-101B-9F08-00AA002F954E}\uninstall.exe Show
To identify and delete AUTORUN.INF files created:
- Right-click the Start button then choose Search... or Find..., depending on the version of Windows you are running.
- In the Named input box, type:
AUTORUN.INF - In the Look in: drop-down list, select a drive, then press Enter.
- Select the file, then open using Notepad.
- Check if the following lines are present in the file:
[autorun]OPEN=recycle.{645FF040-5081-101B-9F08-00AA002F954E}\uninstall.exe
shell\open=´ò¿ª(&O)
shell\open\Command=recycle.{645FF040-5081-101B-9F08-00AA002F954E}\uninstall.exe Show
shell\open\Default=1//
shell\explore=×ÊÔ´¹ÜÀíÆ÷(&X)
shell\explore\Command=recycle.{645FF040-5081-101B-9F08-00AA002F954E}\uninstall.exe Show
- If the lines are present, delete the file.
- Repeat steps 3 to 6 for the remaining AUTORUN.INF files in other remaining removable drives.
- Close Search Results.
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as PE_NIMNUL.A-O. 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%\appmgmts.dll
