BKDR_RVRSE.SMI
Backdoor:Win32/Delf.LB (Microsoft); [00003418.EXE]:BackDoor-DVB.gen.h (McAfee); Backdoor.Trojan (Symantec); Backdoor.Win32.Agent.alqt (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Trojan.Generic.3614575 (FSecure)
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.
It deletes the initially executed copy of itself.
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\Local User
(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)
Autostart Technique
This backdoor 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\360svc\Parameters
Other System Modifications
This backdoor adds the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\360svc
Description = "Ϊ DCOM ·þÎñÌṩ¼ÓÔع¦ÄÜ"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\360svc\Parameters
ServiceDll = "%User Profile%\ntuser.dll"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\360svc
InstallModule = "{malware path and file name}"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\360svc
Type = "12"
It modifies the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\SvcHost
netsvcs = ""6to4,AppMgmt,AudioSrv,Browser,CryptSvc,DMServer,DHCP,ERSvc,EventSystem,FastUserSwitchingCompatibility,HidServ,Ias,Iprip,Irmon,LanmanServer,LanmanWorkstation,Messenger,Netman,Nla,Ntmssvc,NWCWorkstation,Nwsapagent,Rasauto,Rasman,Remoteaccess,Schedule,Seclogon,SENS,Sharedaccess,SRService,Tapisrv,Themes,TrkWks,W32Time,WZCSVC,Wmi,WmdmPmSp,winmgmt,wscsvc,xmlprov,BITS,wuauserv,ShellHWDetection,helpsvc,WmdmPmSN,360svc""
(Note: The default value data of the said registry entry is 6to4.)
Dropping Routine
This backdoor drops the following files:
- %User Profile%\ntuser.dll
(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.)
Other Details
This backdoor deletes the initially executed copy of itself
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_LOCAL_MACHINE\system\cURRENTcONTROLsET\sERVICES\360svc
- Parameters
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\SYSTEM\ControlSet001\Services\360svc
- Description = "Ϊ DCOM ·þÎñÌṩ¼ÓÔع¦ÄÜ"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\360svc\Parameters
- ServiceDll = "%User Profile%\ntuser.dll"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\360svc
- InstallModule = "{malware path and file name}"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\360svc
- Type = "12"
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\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SvcHost
- From: netsvcs = ""6to4,AppMgmt,AudioSrv,Browser,CryptSvc,DMServer,DHCP,ERSvc,EventSystem,FastUserSwitchingCompatibility,HidServ,Ias,Iprip,Irmon,LanmanServer,LanmanWorkstation,Messenger,Netman,Nla,Ntmssvc,NWCWorkstation,Nwsapagent,Rasauto,Rasman,Remoteaccess,Schedule,Seclogon,SENS,Sharedaccess,SRService,Tapisrv,Themes,TrkWks,W32Time,WZCSVC,Wmi,WmdmPmSp,winmgmt,wscsvc,xmlprov,BITS,wuauserv,ShellHWDetection,helpsvc,WmdmPmSN,360svc""
To: netsvcs = "6to4"
- From: netsvcs = ""6to4,AppMgmt,AudioSrv,Browser,CryptSvc,DMServer,DHCP,ERSvc,EventSystem,FastUserSwitchingCompatibility,HidServ,Ias,Iprip,Irmon,LanmanServer,LanmanWorkstation,Messenger,Netman,Nla,Ntmssvc,NWCWorkstation,Nwsapagent,Rasauto,Rasman,Remoteaccess,Schedule,Seclogon,SENS,Sharedaccess,SRService,Tapisrv,Themes,TrkWks,W32Time,WZCSVC,Wmi,WmdmPmSp,winmgmt,wscsvc,xmlprov,BITS,wuauserv,ShellHWDetection,helpsvc,WmdmPmSN,360svc""
Step 6
Search and delete this folder
- %System Root%\Documents and Settings\Local User
Step 7
Search and delete this file
- %User Profile%\ntuser.dll
Step 8
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_RVRSE.SMI. 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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