TROJ_DROPPER.OPU

May 24, 2013
 ALIASES:

PWS:Win32/Stealer.M (Microsoft); Trojan.Dropper (Symantec); Trojan.Win32.Buzus.bsuu (Kaspersky); Net-Worm.Win32.Kolab.ehp (v) (Sunbelt); Trojan horse Generic_r.BU (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.

  TECHNICAL DETAILS

File Size:

1,229,824 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

24 May 2013

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:

  • %Application Data%\Microsoft\Beaver's_SMS_Bomber.exe_Url_4wbvbezvv4mjxpvtzn2wk5ilia2x33py
  • %Application Data%\Microsoft\Beaver's_SMS_Bomber.exe_Url_4wbvbezvv4mjxpvtzn2wk5ilia2x33py\1.0.0.0

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)

Other System Modifications

This Trojan modifies the following file(s):

  • %Application Data%\GDIPFONTCACHEV1.DAT

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
GDIPlus
FontCachePath = "%Application Data%"

(Note: The default value data of the said registry entry is %User Profile%\Local Settings\Application Data.)

Dropping Routine

This Trojan drops the following files:

  • %User Temp%\Beaver's SMS Bomber.exe
  • %User Temp%\u16event.html
  • %Application Data%\Microsoft\Beaver's_SMS_Bomber.exe_Url_4wbvbezvv4mjxpvtzn2wk5ilia2x33py\1.0.0.0\fs0laefl.tmp
  • %Application Data%\Microsoft\Beaver's_SMS_Bomber.exe_Url_4wbvbezvv4mjxpvtzn2wk5ilia2x33py\1.0.0.0\fs0laefl.newcfg
  • %Application Data%\Microsoft\Beaver's_SMS_Bomber.exe_Url_4wbvbezvv4mjxpvtzn2wk5ilia2x33py\1.0.0.0\vswhnd6d.tmp
  • %Application Data%\Microsoft\Beaver's_SMS_Bomber.exe_Url_4wbvbezvv4mjxpvtzn2wk5ilia2x33py\1.0.0.0\vswhnd6d.newcfg
  • %Application Data%\Microsoft\Beaver's_SMS_Bomber.exe_Url_4wbvbezvv4mjxpvtzn2wk5ilia2x33py\1.0.0.0\w-u5nsbm.tmp
  • %Application Data%\Microsoft\Beaver's_SMS_Bomber.exe_Url_4wbvbezvv4mjxpvtzn2wk5ilia2x33py\1.0.0.0\w-u5nsbm.newcfg
  • %Application Data%\Microsoft\Beaver's_SMS_Bomber.exe_Url_4wbvbezvv4mjxpvtzn2wk5ilia2x33py\1.0.0.0\bguklrof.tmp
  • %Application Data%\Microsoft\Beaver's_SMS_Bomber.exe_Url_4wbvbezvv4mjxpvtzn2wk5ilia2x33py\1.0.0.0\bguklrof.newcfg

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.. %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)

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

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\GDIPlus
    • From: FontCachePath = "%Application Data%"
      To: FontCachePath = ""%User Profile%\Local Settings\Application Data""

Step 3

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.
  • %User Temp%\Beaver's SMS Bomber.exe
  • %User Temp%\u16event.html
  • %Application Data%\Microsoft\Beaver's_SMS_Bomber.exe_Url_4wbvbezvv4mjxpvtzn2wk5ilia2x33py\1.0.0.0\fs0laefl.tmp
  • %Application Data%\Microsoft\Beaver's_SMS_Bomber.exe_Url_4wbvbezvv4mjxpvtzn2wk5ilia2x33py\1.0.0.0\fs0laefl.newcfg
  • %Application Data%\Microsoft\Beaver's_SMS_Bomber.exe_Url_4wbvbezvv4mjxpvtzn2wk5ilia2x33py\1.0.0.0\vswhnd6d.tmp
  • %Application Data%\Microsoft\Beaver's_SMS_Bomber.exe_Url_4wbvbezvv4mjxpvtzn2wk5ilia2x33py\1.0.0.0\vswhnd6d.newcfg
  • %Application Data%\Microsoft\Beaver's_SMS_Bomber.exe_Url_4wbvbezvv4mjxpvtzn2wk5ilia2x33py\1.0.0.0\w-u5nsbm.tmp
  • %Application Data%\Microsoft\Beaver's_SMS_Bomber.exe_Url_4wbvbezvv4mjxpvtzn2wk5ilia2x33py\1.0.0.0\w-u5nsbm.newcfg
  • %Application Data%\Microsoft\Beaver's_SMS_Bomber.exe_Url_4wbvbezvv4mjxpvtzn2wk5ilia2x33py\1.0.0.0\bguklrof.tmp
  • %Application Data%\Microsoft\Beaver's_SMS_Bomber.exe_Url_4wbvbezvv4mjxpvtzn2wk5ilia2x33py\1.0.0.0\bguklrof.newcfg

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%\Microsoft\Beaver's_SMS_Bomber.exe_Url_4wbvbezvv4mjxpvtzn2wk5ilia2x33py
  • %Application Data%\Microsoft\Beaver's_SMS_Bomber.exe_Url_4wbvbezvv4mjxpvtzn2wk5ilia2x33py\1.0.0.0

Step 5

Scan your computer with your Trend Micro product to delete files detected as TROJ_DROPPER.OPU. 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.

Step 6

Restore deleted/modified files and/or registry entries from backup

*Note: Only Microsoft-related files/keys/values will be restored. If this malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.

    • %Application Data%\GDIPFONTCACHEV1.DAT


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