Modified by: Jennifer Gumban
 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It modifies the Internet Explorer Zone Settings.

  TECHNICAL DETAILS

File Size: 44,544 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 14 Feb 2014

Arrival Details

This backdoor 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 backdoor drops the following copies of itself into the affected system:

  • %User Profile%\Application Data\winrar.exe
  • %User Startup%\f181b87b5e994ddc44f095ec70fd0f2c.exe

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.. %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup.)

Autostart Technique

This backdoor adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
f181b87b5e994ddc44f095ec70fd0f2c = "%User Profile%\Application Data\winrar.exe .."

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
f181b87b5e994ddc44f095ec70fd0f2c = "%User Profile%\Application Data\winrar.exe .."

Other System Modifications

This backdoor adds the following registry keys:

HKEY_CURRENT_USER\Software\f181b87b5e994ddc44f095ec70fd0f2c

It adds the following registry entries:

HKEY_CURRENT_USER\Software\f181b87b5e994ddc44f095ec70fd0f2c
US = "{random symbol}"

HKEY_CURRENT_USER\Environment
SEE_MASK_NOZONECHECKS = "1"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%User Profile%\Application Data\winrar.exe = "{random characters}"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Tracing\
Microsoft\{random value}
Active = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Tracing\
Microsoft\{random value}
ControlFlags = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Tracing\
Microsoft\{random value}
LogSessionName = "stdout"

Web Browser Home Page and Search Page Modification

This backdoor modifies the Internet Explorer Zone Settings.

Dropping Routine

This backdoor drops the following files:

  • %User Profile%\Application Data\winrar.exe.tmp

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

Other Details

This backdoor connects to the following possibly malicious URL:

  • http://{BLOCKED}r.{BLOCKED}ties.com

  SOLUTION

Minimum Scan Engine: 9.300
FIRST VSAPI PATTERN FILE: 10.606.01
FIRST VSAPI PATTERN DATE: 14 Feb 2014
VSAPI OPR PATTERN File: 10.607.00
VSAPI OPR PATTERN Date: 15 Feb 2014

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 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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Tracing\Microsoft
    • {random value} = ""
  • In HKEY_CURRENT_USER\Software
    • f181b87b5e994ddc44f095ec70fd0f2c = ""

Step 4

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
    • f181b87b5e994ddc44f095ec70fd0f2c = "%User Profile%\Application Data\winrar.exe .."
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • f181b87b5e994ddc44f095ec70fd0f2c = "%User Profile%\Application Data\winrar.exe .."
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • %User Profile%\Application Data\winrar.exe = "{random characters}"
  • In HKEY_CURRENT_USER\Environment
    • SEE_MASK_NOZONECHECKS = "1"

Step 5

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 Profile%\Application Data\winrar.exe.tmp

Step 6

Reset Internet security settings

[ Learn More ]

Step 7

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