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: 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.

It modifies the Internet Explorer Zone Settings.

It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size: 383,488 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 05 Feb 2014

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 copies of itself into the affected system:

  • %All Users Profile%\Application Data\{random folder name 1}\{random name 1}.exe

(Note: %All Users Profile% is the All Users or Common profile folder, which is C:\Documents and Settings\All Users in Windows 2000, XP, and Server 2003, and C:\ProgramData in Windows Vista and 7.)

Autostart Technique

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

{KEY}\Software\Microsoft\
Windows NT\CurrentVersion\Winlogon
shell = "%All Users Profile%\Application Data\{random folder name}\{random name}.exe,explorer.exe"

{KEY}\Software\Microsoft\
Windows\CurrentVersion\RunOnce
{random key} = "%All Users Profile%\Application Data\{random folder}\{random file name}.exe"

Web Browser Home Page and Search Page Modification

This Trojan modifies the Internet Explorer Zone Settings.

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}cconverter.biz

It drops the following file(s)/component(s):

  • %All Users Profile%\Application Data\{random folder name 2}\{random name 2}.{3 random letters}
  • %SystemRoot%\{random name}.{3 random letters}

(Note: %All Users Profile% is the All Users or Common profile folder, which is C:\Documents and Settings\All Users in Windows 2000, XP, and Server 2003, and C:\ProgramData in Windows Vista and 7.)

It deletes the initially executed copy of itself

NOTES:

It connects to the following randomized domain with the ff. extensions:

  • .info
  • .com
  • .biz
  • .org
  • .net
  • .ru

Where {KEY} can be the ff.:

  • HKEY_CURRENT_USER
  • HKEY_USERS \.DEFAULT
  • HKEY_USERS \{SID}

  SOLUTION

Minimum Scan Engine: 9.300
FIRST VSAPI PATTERN FILE: 10.585.80
FIRST VSAPI PATTERN DATE: 04 Feb 2014
VSAPI OPR PATTERN File: 10.586.00
VSAPI OPR PATTERN Date: 05 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

Scan your computer with your Trend Micro product and note files detected as TROJ_SHARIK.LS

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 {KEY}\Software\Microsoft\Windows NT\CurrentVersion\Winlogon
    • shell = "%All Users Profile%\Application Data\{random folder name}\{random name}.exe,explorer.exe"
  • In {KEY}\Software\Microsoft\Windows\CurrentVersion\RunOnce
    • {random key} = "%All Users Profile%\Application Data\{random folder}\{random file name}.exe"

Step 4

Search and delete these files

[ 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.
  • %All Users Profile%\Application Data\{random folder name 2}\{random name 2}.{3 random letters}
  • %SystemRoot%\{random name}.{3 random letters}

Step 5

Reset Internet security settings

[ Learn More ]

Step 6

Scan your computer with your Trend Micro product to delete files detected as TROJ_SHARIK.LS. 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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