TROJ_DLOADR.SMAF

October 09, 2012
 Analysis by: rolandde
 ALIASES:

TrojanDownloader:Win32/Fakr.A (Microsoft); Trojan-Downloader.Win32.Adload.cfnk (Kaspersky)

 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 arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites. It may be downloaded by other malware/grayware/spyware from remote sites.

  TECHNICAL DETAILS

File Size:

Varies

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

01 Dec 2011

Payload:

Downloads files

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.

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

Installation

This Trojan drops the following non-malicious file:

  • %System%\sircheckfile.dat - log file

(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.)

It creates the following folders:

  • %Application Data%\finalget
  • %Application Data%\ozplus
  • %Progpram Files%\one-step
  • %Application Data%\dd80

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

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
one-step = %Program Files%\one-step\one-stepe.exe

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
finalgetv3 = %Application Data%\finalgets.exe

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
ozplusv3 = %Application Data%\ozpluss.exe

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
dd80 = %Application Data%\dd80.exe

Other System Modifications

This Trojan adds the following registry keys as part of its installation routine:

HKEY_CURRENT_USER\Software\alsef

HKEY_CURRENT_USER\Software\dd80

HKEY_CURRENT_USER\Software\finalgetpp

HKEY_CURRENT_USER\Software\noone-step

HKEY_CURRENT_USER\Software\one-step

HKEY_CURRENT_USER\Software\ozpluspp

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\App Management\
ARPCache\dd80

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\App Management\
ARPCache\finalget

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\App Management\
ARPCache\ozplus

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
dd80

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
finalget

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
ozplus

NOTES:

Download Routine

It connects to the following sites to get download instructions:

  • http://{BLOCKED}erpop.co.kr/projelist3.php
  • http://{BLOCKED}nalget.co.kr/update.php
  • http://{BLOCKED}erpop.co.kr/projelist3.php
  • http://{BLOCKED}plus.kr/update.php
  • http://{BLOCKED}e-step.kr/link/config.php
  • http://{BLOCKED}80.kr/update.php - inaccessible

It then proceeds with downloading the following files:

  • http://{BLOCKED}alget.co.kr/finalget.zip
  • http://{BLOCKED}lus.kr/ozplus.zip
  • http://{BLOCKED}ne-step.kr/install/one-step.zip
  • http://{BLOCKED}0.kr/dd80.zip - inaccessible

It initially saves the archive it downloads as %System%\{archive filename}.zip. It then proceeds with extracting the contents of the downloaded archive in the following folders:

  • %Application Data%\dd80
  • %Application Data%\finalget
  • %Application Data%\ozplus
  • %Progpram Files%\one-step
The extracted files are saved as follows:
  • %Application Data%\finalget\finalget.dll detected as TROJ_DLOADR.KPW
  • %Application Data%\finalget\finalgets.exe detected as TROJ_DLOADR.KPW
  • %Application Data%\finalget\uninstall.exe detected as TROJ_FAKR.FJS
  • %Application Data%\finalget\evdat2.dmc - non-malicious component
  • %Application Data%\ozplus\ozplus.dll detected as TROJ_BSDD.DUKKS
  • %Application Data%\ozplus\ozpluss.exe detected as TROJ_BSDD.DUKKS
  • %Application Data%\ozplus\uninstall.exe detected as TROJ_FAKR.FJS
  • %Application Data%\ozplus\evdat2.dmc - non-malicious component
  • %Progpram Files%\one-step\one-step.dll detected as TROJ_DLOADR.AGN
  • %Progpram Files%\one-step\one-stepb.dll detected as TROJ_DLOADR.AGN
  • %Progpram Files%\one-step\one-stepe.exe detected as TROJ_DLOADR.AGN
  • %Progpram Files%\one-step\uninstall.exe detected as TROJ_FAKR.FJS
  • %Progpram Files%\one-step\ls.plc - non-malicious component

It then executes the extracted files. As a result, malicious routines of these files are also exhibited on the affected system.

It deletes the initially saved archive %System%\{archive filename}.zip.

It reports download success to the following sites:

  • http://www.{BLOCKED}s.kr/count/inst.php?pid={parameter}&kind=i
  • http://www.{BLOCKED}get.co.kr/count/inst.php?pid={parameter}&kind=i
  • http://www.{BLOCKED}tep.kr/count/install_count.php?pid={parameter}&kind=i
  • http://www.{BLOCKED}kr/count/inst.php?pid={parameter}&kind=i

  SOLUTION

Minimum Scan Engine:

9.200

VSAPI OPR PATTERN File:

8.623.00

VSAPI OPR PATTERN Date:

03 Dec 2011

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

Remove malware files dropped/downloaded by TROJ_DLOADR.SMAF

    • TROJ_BSDD.DUKKS
    • TROJ_DLOADR.AGN
    • TROJ_DLOADR.KPW
    • TROJ_FAKR.FJS

Step 3

Search and delete this file

[ 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. %System%\sircheckfile.dat

Step 4

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.  %Application Data%\finalget
%Application Data%\ozplus
%Progpram Files%\one-step
%Application Data%\dd80

Step 5

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. Before you could do this, you must restart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires you to restart in safe mode, you may proceed to edit the system registry.

  • In HKEY_CURRENT_USER\Software
    • alsef
  • In HKEY_CURRENT_USER\Software
    • dd80
  • In HKEY_CURRENT_USER\Software
    • finalgetpp
  • In HKEY_CURRENT_USER\Software
    • noone-step
  • In HKEY_CURRENT_USER\Software
    • one-step
  • In HKEY_CURRENT_USER\Software
    • ozpluspp
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Management\ARPCache
    • dd80
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Management\ARPCache
    • finalget
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Management\ARPCache
    • ozplus
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall
    • dd80
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall
    • finalget
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall
    • ozplus

Step 6

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
    • one-step = %Program Files%\one-step\one-stepe.exe
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • finalgetv3 = %Application Data%\finalgets.exe
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • ozplusv3 = %Application Data%\ozpluss.exe
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • dd80 = %Application Data%\dd80.exe

Step 7

Scan your computer with your Trend Micro product to delete files detected as TROJ_DLOADR.SMAF. 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.

NOTES:

Recommendations

  • Enable firewall to protect against threats.
  • Block unused ports to disallow malware from using these ports to communicate and/or enforce commands.
  • Be aware of social engineering attacks.
  • Avoid accessing the listed malicious URLs to prevent possible re-infection.
  • Monitor network connections for any suspicious connection or connectivity.
  • Regularly update list of sites that are trusted.
  • Avoid downloading software cracks and/or pirated applications.
  • Clear browser cache and delete cookies regularly.
  • Delete files in the %User Temp% folder.


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