TROJ_DELF.CVT
ERROR (Microsoft); RDN/Downloader.a!jv (McAfee); Infostealer.Gamania (Symantec); Trojan-Dropper.Win32.Delf.ze (Kaspersky); Packed.Win32.Upack (v) (Sunbelt); Trojan horse Dropper.Generic.GSL (AVG)
Windows 2000, Windows XP, Windows Server 2003
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
571,710 bytes
EXE
Yes
26 Jul 2013
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.
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
NTdhcp = "%System%\NTdhcp.exe"
It registers as a system service to ensure its automatic execution at every system startup by adding the following registry keys:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\navapsvc
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\RsRavMon
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\RsCCenter
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\kavsvc
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\KVSrvXP
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\KVWSC
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\KPfwSvc
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\KWatchSvc
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SNDSrvc
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\ccProxy
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\ccEvtMgr
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\ccSetMgr
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SPBBCSvc
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Symantec Core LC
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\NPFMntor
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\MskService
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\FireSvc
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\McShield
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\McTaskManager
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\McAfeeFramework
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\RfwService
Other System Modifications
This Trojan adds the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\navapsvc
Start = "4"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\RsRavMon
Start = "4"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\RsCCenter
Start = "4"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\kavsvc
Start = "4"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\KVSrvXP
Start = "4"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\KVWSC
Start = "4"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\KPfwSvc
Start = "4"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\KWatchSvc
Start = "4"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SNDSrvc
Start = "4"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\ccProxy
Start = "4"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\ccEvtMgr
Start = "4"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\ccSetMgr
Start = "4"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SPBBCSvc
Start = "4"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Symantec Core LC
Start = "4"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\NPFMntor
Start = "4"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\MskService
Start = "4"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\FireSvc
Start = "4"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\McShield
Start = "4"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\McTaskManager
Start = "4"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\McAfeeFramework
Start = "4"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\RfwService
Start = "4"
HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Check_Associations = "no"
It modifies the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\wscsvc
Start = "4"
(Note: The default value data of the said registry entry is 2.)
HKEY_CURRENT_USER\Software\Microsoft\
Internet Connection Wizard
Completed = "{random values}"
(Note: The default value data of the said registry entry is 1.)
Dropping Routine
This Trojan drops the following files:
- %System Root%\xiaoma.exe
- %System Root%\Setup.exe
- %Windows%\Deleteme.bat
- %Windows%\uninstal.bat
- %Windows%\svchost.DLL
- %Windows%\svchostKey.DLL
- %System%\KvNative.bak
- %System%\NTdHcP.exe
- %Windows%\svchost.exe
(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %Windows% is the Windows folder, which is usually C:\Windows.. %System% is the Windows system folder, which is usually C:\Windows\System32.)
Other Details
This Trojan connects to the following possibly malicious URL:
- http://mitaoxiang.{BLOCKED}y.myrice.com/ip.txt
This report is generated via an automated analysis system.
SOLUTION
9.300
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_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- navapsvc
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- RsRavMon
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- RsCCenter
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- kavsvc
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- KVSrvXP
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- KVWSC
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- KPfwSvc
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- KWatchSvc
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- SNDSrvc
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- ccProxy
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- ccEvtMgr
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- ccSetMgr
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- SPBBCSvc
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- Symantec Core LC
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- NPFMntor
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- MskService
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- FireSvc
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- McShield
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- McTaskManager
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- McAfeeFramework
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- RfwService
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
- NTdhcp = "%System%\NTdhcp.exe"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\navapsvc
- Start = "4"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\RsRavMon
- Start = "4"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\RsCCenter
- Start = "4"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\kavsvc
- Start = "4"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\KVSrvXP
- Start = "4"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\KVWSC
- Start = "4"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\KPfwSvc
- Start = "4"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\KWatchSvc
- Start = "4"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SNDSrvc
- Start = "4"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\ccProxy
- Start = "4"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\ccEvtMgr
- Start = "4"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\ccSetMgr
- Start = "4"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SPBBCSvc
- Start = "4"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Symantec Core LC
- Start = "4"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\NPFMntor
- Start = "4"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\MskService
- Start = "4"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\FireSvc
- Start = "4"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\McShield
- Start = "4"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\McTaskManager
- Start = "4"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\McAfeeFramework
- Start = "4"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\RfwService
- Start = "4"
- In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
- Check_Associations = "no"
Step 5
Restore these modified registry values
Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\wscsvc
- From: Start = "4"
To: Start = ""2""
- From: Start = "4"
- In HKEY_CURRENT_USER\Software\Microsoft\Internet Connection Wizard
- From: Completed = "{random values}"
To: Completed = ""1""
- From: Completed = "{random values}"
Step 6
Search and delete these components
- %System Root%\xiaoma.exe
- %System Root%\Setup.exe
- %Windows%\Deleteme.bat
- %Windows%\uninstal.bat
- %Windows%\svchost.DLL
- %Windows%\svchostKey.DLL
- %System%\KvNative.bak
- %System%\NTdHcP.exe
- %Windows%\svchost.exe
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_DELF.CVT. 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.
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