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TROJ_SASFIS.JA

October 08, 2012
 Analysis by: jasperm
 PLATFORM:

Windows 2000, XP, Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This Trojan may be dropped by other malware. It may be unknowingly downloaded by a user while visiting malicious websites. However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size:

31,744 bytes

File Type:

PE

Memory Resident:

Yes

Initial Samples Received Date:

24 Sep 2010

Payload:

Downloads files

Arrival Details

This Trojan may be dropped by other malware.

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

However, as of this writing, the said sites are inaccessible.

Autostart Technique

This Trojan modifies the following registry entry(ies) to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NTNT\CurrentVersion\Winlogon
Shell = Explorer.exe rundll32.exe bfky.ojo bwapp

(Note: The default value data of the said registry entry is Explorer.exe.)

It drops the following files:

  • %System%bfky.ojo - also detected as TROJ_SASFIS.JA

(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 System Modifications

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

HKEY_CLASSES_ROOT\idid

Download Routine

This Trojan accesses the following websites to download files:

  • {BLOCKED}o-viagra.ru

  SOLUTION

Minimum Scan Engine:

8.900

VSAPI PATTERN File:

7.489.80

VSAPI PATTERN Date:

24 Sep 2010

VSAPI PATTERN Date:

9/24/2010 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

Scan your computer with your Trend Micro product and note files detected as TROJ_SASFIS.JA

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

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.

RESTORE
  • Close Registry Editor.

    • 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.

    RESTORE
  • Close Registry Editor.

    • Step 6

    Scan your computer with your Trend Micro product to delete files detected as TROJ_SASFIS.JA. 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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