TROJ_INJECT.ES

October 08, 2012
 Analysis by: Michael Cabel
 Modified by: Kathleen Notario
 ALIASES:

Kaspersky: Trojan.Win32.Buzus.gxej

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

This Trojan may be downloaded by other malware/grayware/spyware from remote sites. It may be unknowingly downloaded by a user while visiting malicious websites.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size:

1,699,328 bytes

File Type:

PE

Memory Resident:

Yes

Initial Samples Received Date:

10 Feb 2011

Arrival Details

This Trojan may be downloaded by other malware/grayware/spyware from remote sites.

It may be unknowingly downloaded by a user while visiting malicious websites.

Installation

This Trojan drops the following non-malicious files:

  • %Current%\tl 1300-0014.doc
  • %Current%\{malware filename}.exe.bat

It drops the following copies of itself into the affected system:

  • %Program Files%\Microsoft\winhosts.exe

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files.)

It injects threads into the following normal process(es):

  • iexplore.exe

Autostart Technique

This Trojan adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Microsoft Office = "%Program Files%\Microsoft\winhosts.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Microsoft Office = "%Program Files%\Microsoft\winhosts.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{161773E5-5567-0C2C-5ED0-E1CAA4CD2A9E}
StubPath = %System%\ysconfiging.exe

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{161773E5-5567-0C2C-5ED0-E1CAA4CD2A9E}

It adds the following registry entries as part of its installation routine:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{YQJRKPOF-1WOJ-M311-06GK-5TA6F41B1560}
StubPath = "%Program Files%\Microsoft\winhosts.exe restart"

Dropping Routine

This Trojan drops the following files:

  • %System%\ysconfiging.exe - also detected as TROJ_INJECT.ES

(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 Trojan connects to the following possibly malicious URL:

  • {BLOCKED}7.mydynip.net

It deletes itself after execution.

  SOLUTION

Minimum Scan Engine:

8.900

VSAPI PATTERN File:

7.828.11

VSAPI PATTERN Date:

10 Feb 2011

VSAPI PATTERN Date:

2/10/2011 12:00:00 AM

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 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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • Microsoft Office = %Program Files%\Microsoft\winhosts.exe
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • Microsoft Office = %Program Files%\Microsoft\winhosts.exe
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components\{161773E5-5567-0C2C-5ED0-E1CAA4CD2A9E}
    • StubPath = %System%\ysconfiging.exe
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components\{YQJRKPOF-1WOJ-M311-06GK-5TA6F41B1560}
    • StubPath = %Program Files%\Microsoft\winhosts.exe restart

Step 4

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_CURRENT_USER\Software
    • Local AppWizard-Generated Applications
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components
    • {161773E5-5567-0C2C-5ED0-E1CAA4CD2A9E}

Step 5

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. %Current%\tl 1300-0014.doc
%Current%\{malware filename}.exe.bat

Step 6

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