TROJ_DROPPR.EBF


 ALIASES:

Dagis (McAfee); Trojan Horse (Symantec); Trojan.Win32.Agent.agj (Kaspersky); BehavesLike.Win32.Malware.eah (mx-v) (Sunbelt); Trojan horse Generic3.ADD (AVG)

 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.

It disables Task Manager, Registry Editor, and Folder Options.

  TECHNICAL DETAILS

File Size:

58,880 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

08 May 2014

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_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
WindowsControl = "%System%\wctrl.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
winampa = "%System%\winampa.exe"

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System

It modifies the following registry entries:

HKEY_CURRENT_USER\Control Panel\Desktop
SCRNSAVE.EXE = "%Windows%\GADISS~1.SCR"

(Note: The default value data of the said registry entry is %Windows%\system32\logon.scr.)

It creates the following registry entry(ies) to disable Task Manager, Registry Tools and Folder Options:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableRegistryTools = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableTaskMgr = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
NoFolderOptions = "1"

Dropping Routine

This Trojan drops the following files:

  • %System%\winampa.exe
  • %System%\wctrl.exe
  • %System%\Gadis Seksi.scr
  • %Windows%\update2
  • %Windows%\fc2
  • %System Root%\bo2
  • E:\bo2
  • F:\bo2
  • G:\bo2
  • H:\bo2
  • I:\bo2
  • J:\bo2
  • K:\bo2
  • L:\bo2
  • M:\bo2
  • N:\bo2
  • O:\bo2
  • P:\bo2
  • Q:\bo2
  • R:\bo2
  • S:\bo2
  • T:\bo2
  • U:\bo2
  • V:\bo2
  • W:\bo2
  • X:\bo2
  • Y:\bo2
  • Z:\bo2

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.. %Windows% is the Windows folder, which is usually C:\Windows.. %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

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

[ Learn More ]

Step 3

Enable Registry Editor, Task Manager, and Folder options

[ Learn More ]
By doing this step, you also enable other applications/programs disabled by this malware/grayware/spyware.

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\Microsoft\Windows\CurrentVersion\Policies
    • System

Step 5

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
    • WindowsControl = "%System%\wctrl.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • winampa = "%System%\winampa.exe"

Step 6

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\Control Panel\Desktop
    • From: SCRNSAVE.EXE = "%Windows%\GADISS~1.SCR"
      To: SCRNSAVE.EXE = ""%Windows%\system32\logon.scr""

Step 7

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.
  • %System%\winampa.exe
  • %System%\wctrl.exe
  • %System%\Gadis Seksi.scr
  • %Windows%\update2
  • %Windows%\fc2
  • %System Root%\bo2
  • E:\bo2
  • F:\bo2
  • G:\bo2
  • H:\bo2
  • I:\bo2
  • J:\bo2
  • K:\bo2
  • L:\bo2
  • M:\bo2
  • N:\bo2
  • O:\bo2
  • P:\bo2
  • Q:\bo2
  • R:\bo2
  • S:\bo2
  • T:\bo2
  • U:\bo2
  • V:\bo2
  • W:\bo2
  • X:\bo2
  • Y:\bo2
  • Z:\bo2

Step 8

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