Modified by: Kathleen Notario

 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.

  TECHNICAL DETAILS

File Size: 51,712 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 26 Sep 2009

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 drops the following files:

  • %System%\braviax.exe
  • %System%\dllcache\figaro.sys

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

Other System Modifications

This Trojan modifies the following file(s):

  • %System%\dllcache\beep.sys
  • %System%\drivers\beep.sys

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Download
RunInvalidSignatures = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Associations
LowRiskFileTypes = "zip;.rar;.cab;.txt;.exe;.reg;.msi;.htm;.html;.gif;.bmp;.jpg;.avi;.mov;.mp3;.wav"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Associations
SaveZoneInformation = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
braviax = "%System%\braviax.exe"

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

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Download
CheckExeSignatures = "no"

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

Download Routine

This Trojan accesses the following websites to download files:

  • http://{BLOCKED}herproger.com/d1S0z1NMW9loO0q4S1FrB0mQG6OKA
  • http://{BLOCKED}aguliermot.com/qn1gy0xG1FJF9teD0Hz4vik1X0fy6nA
  • http://{BLOCKED}dertogafe.com/gO1qxv0V1tRN9tO0VFy4D1ma0qW6V
  • http://{BLOCKED}masekasuke.com/U1q0YsP1A9zZ0OWl4Yp1QEf0Hf/6h/d
  • http://{BLOCKED}domegase.com/Hm1yb0ACF1gz9JoX0zbj4y1Uw0sq6r
  • http://{BLOCKED}agulermos.com/h1J0F1eGx9bi0Ay4Cf1iO0k6lEW
  • http://{BLOCKED}komandar.com/g1c0koa1Hn9f0WQC4if1cp0Hm6PZ
  • http://{BLOCKED}anosetrat.com/gIh1a0K1ik9C0rYS4zr1jGz0SnA6b
  • http://{BLOCKED}afoterkos.com/b/b1ftK0sV1oRr9Mk0Maz4Dbq1P0NPo6x

It saves the files it downloads using the following names:

  • %System%\wisdstr.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

  SOLUTION

Minimum Scan Engine: 9.200
FIRST VSAPI PATTERN FILE: 6.480.02
FIRST VSAPI PATTERN DATE: 26 Sep 2009
VSAPI OPR PATTERN File: 6.481.00
VSAPI OPR PATTERN Date: 28 Sep 2009

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 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\Internet Explorer\Download
    • RunInvalidSignatures = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Associations
    • LowRiskFileTypes = "zip;.rar;.cab;.txt;.exe;.reg;.msi;.htm;.html;.gif;.bmp;.jpg;.avi;.mov;.mp3;.wav"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Associations
    • SaveZoneInformation = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • braviax = "%System%\braviax.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • braviax = "%System%\braviax.exe"

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.

  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Download
    • From: CheckExeSignatures = "no"
      To: CheckExeSignatures = "yes"

Step 5

Search and delete this file

[ Learn More ]
There may be some 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%\braviax.exe
  • %System%\dllcache\figaro.sys
  • %System%\wisdstr.exe

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_FAKEALE.SMB. 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 7

Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.

  • %System%\dllcache\beep.sys
  • %System%\drivers\beep.sys


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