TROJ_DROPPER.EJRQ


 ALIASES:

Mal/Dorf-A (Sophos); Found Win32/DH{gRN5IA8AZzU} (AVG)

 PLATFORM:

Windows

 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:

178,688 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

14 Jan 2015

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:

  • %User Temp%\Hs_
  • %Application Data%\SSI
  • %User Temp%\5414
  • %User Temp%\5060
  • %User Temp%\1255

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.. %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

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
syotom = "{malware path and file name}"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
SSIagent = "%Application Data%\SSI\SSIagent.exe /byboot"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
SSI = "%Application Data%\SSI\SSI.exe /byboot"

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Windows Script\Settings

HKEY_CURRENT_USER\Software\Microsoft\
SSIagent

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
{malware path and file name} = "{malware path and file name}:*:enabled:sevsl"

HKEY_CURRENT_USER\Software\Microsoft\
Windows Script\Settings
JITDebug = "0"

HKEY_CURRENT_USER\Software\Microsoft\
SSIagent
SSIagentpc = "{random characters}"

HKEY_CURRENT_USER\Software\Microsoft\
SSIagent
SSIagentc = "{random characters}"

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Start Page = "www.naver.com"

(Note: The default value data of the said registry entry is http://www.microsoft.com/isapi/redir.dll?prd=ie&pver=6&ar=msnhome.)

Dropping Routine

This Trojan drops the following files:

  • %Windows%\SSIagent.exe
  • %Temporary Internet Files%\Content.IE5\ZDGZNKA5\cgi_personal_card[1]
  • %Temporary Internet Files%\Content.IE5\BVLBNMKH\ip[1].htm
  • %User Temp%\58b8052567ade6540adf05ec8d813970.zip
  • %Temporary Internet Files%\Content.IE5\09RWHJQN\upload[1].htm
  • %Application Data%\SSI\utp.exe
  • %User Temp%\5414\ssub.exe
  • %User Temp%\5060\windowstab.dll
  • %User Temp%\1255\SSI.exe
  • %Application Data%\SSI\windowstab.dll
  • %Application Data%\SSI\SSI.exe

(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.. %Temporary Internet Files% is the Temporary Internet Files folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temporary Internet Files on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Microsoft\Windows\Temporary Internet Files on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), and Windows Server 2008; C:\Users\{user name}\AppData\Local\Microsoft\Windows\INetCache on Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), and Windows Server 2012.. %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.. %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}8.32.78
  • http://api.{BLOCKED}i.net/ssi/fpd.php?pid=defapp&cid=0050569f76c5
  • http://api.{BLOCKED}i.net/ssi/df/SSIagent.exe
  • http://api.{BLOCKED}i.net/ssi/log.php?{random characters}
  • http://api.{BLOCKED}i.net/ssi/df/ssub.exe
  • http://api.{BLOCKED}i.net/ssi/df/windowstab.dll
  • http://api.{BLOCKED}i.net/ssi/df/SSI.exe
  • {BLOCKED}0.1
  • {BLOCKED}.105.72
  • {BLOCKED}3.49.83
  • {BLOCKED}.102.134

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.700

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

[ 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_CURRENT_USER\Software\Microsoft\Windows Script
    • Settings
  • In HKEY_CURRENT_USER\Software\Microsoft
    • SSIagent

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\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • syotom = "{malware path and file name}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • SSIagent = "%Application Data%\SSI\SSIagent.exe /byboot"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • SSI = "%Application Data%\SSI\SSI.exe /byboot"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • {malware path and file name} = "{malware path and file name}:*:enabled:sevsl"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows Script\Settings
    • JITDebug = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\SSIagent
    • SSIagentpc = "{random characters}"
  • In HKEY_CURRENT_USER\Software\Microsoft\SSIagent
    • SSIagentc = "{random characters}"

Step 5

Restore these modified registry values

[ Learn More ]

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_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • From: Start Page = "www.naver.com"
      To: Start Page = ""http://www.microsoft.com/isapi/redir.dll?prd=ie&pver=6&ar=msnhome""

Step 6

Search and delete these components

[ Learn More ]
There may be some components 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%\SSIagent.exe
  • %Temporary Internet Files%\Content.IE5\ZDGZNKA5\cgi_personal_card[1]
  • %Temporary Internet Files%\Content.IE5\BVLBNMKH\ip[1].htm
  • %User Temp%\58b8052567ade6540adf05ec8d813970.zip
  • %Temporary Internet Files%\Content.IE5\09RWHJQN\upload[1].htm
  • %Application Data%\SSI\utp.exe
  • %User Temp%\5414\ssub.exe
  • %User Temp%\5060\windowstab.dll
  • %User Temp%\1255\SSI.exe
  • %Application Data%\SSI\windowstab.dll
  • %Application Data%\SSI\SSI.exe

Step 7

Search and delete these folders

[ 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.
  • %User Temp%\Hs_
  • %Application Data%\SSI
  • %User Temp%\5414
  • %User Temp%\5060
  • %User Temp%\1255

Step 8

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