TROJ_SMALLTR.AIE


 ALIASES:

Backdoor:Win32/Delf.LB (Microsoft); MultiDropper-JD (McAfee); Trojan Horse (Symantec); ARC:EmbeddedEXE (Kaspersky); Trojan.Win32.Generic!SB.0 (Sunbelt); Trojan.Generic.2553509 (FSecure)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • 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

File Size:

1,077,550 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

20 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 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 Trojan 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 Trojan adds the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\MediaResources\msvideo

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\360svc
Description = "¼à²âºÍ¼àÊÓÐÂÓ²¼þÉ豸²¢×Ô¶¯¸üÐÂÉ豸Çý¶¯¡£"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\360svc\Parameters
ServiceDll = "%User Profile%\ntuser.dll"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\360svc\Parameters
ServiceMain = "newfunction"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\360svc
InstallModule = "%Windows%\1.exe"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\360svc
Type = "12"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\SvcHost
rpcss = "RpcSs,360svc"

(Note: The default value data of the said registry entry is {random values}.)

Dropping Routine

This Trojan drops the following files:

  • %Windows%\1.exe
  • %Windows%\ResHacker.exe
  • %User Profile%\ntuser.dll
  • %System%\sysrecord.key

(Note: %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.. %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.. %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

Minimum Scan Engine:

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

[ Learn More ]

Step 3

Delete this registry key

[ Learn More ]

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
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\MediaResources
    • msvideo

Step 4

Delete this registry value

[ Learn More ]

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 = "¼à²âºÍ¼àÊÓÐÂÓ²¼þÉ豸²¢×Ô¶¯¸üÐÂÉ豸Çý¶¯¡£"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\360svc\Parameters
    • ServiceDll = "%User Profile%\ntuser.dll"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\360svc\Parameters
    • ServiceMain = "newfunction"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\360svc
    • InstallModule = "%Windows%\1.exe"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\360svc
    • Type = "12"

Step 5

Restore this modified registry value

[ Learn More ]

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\SvcHost
    • From: rpcss = "RpcSs,360svc"
      To: rpcss = ""{random values}""

Step 6

Search and delete these files

[ Learn More ]
There may be some component files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
  • %Windows%\1.exe
  • %Windows%\ResHacker.exe
  • %User Profile%\ntuser.dll
  • %System%\sysrecord.key

Step 7

Search and delete this folder

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %System Root%\Documents and Settings\Local User

Step 8

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_SMALLTR.AIE. 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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