VBS_OLEAR.SM

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 may be hosted on a website and run when a user accesses the said website.

It executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

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.

It may be hosted on a website and run when a user accesses the said website.

Installation

This Trojan drops the following component file(s):

• %User Temp%\Uninstall.Vbs - detected as HKTL_DLOADER.C
• %User Temp%\uninst.gif.vbs - detected as HKTL_DLOADER.C

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

Dropping Routine

This Trojan takes advantage of the following software vulnerabilities to drop malicious files:

• CVE-2014-6332

Download Routine

This Trojan connects to the following URL(s) to download its component file(s):

• http://{BLOCKED}eong.com/files/oms.exe
• http://{BLOCKED}os.co.kr/new/media/apple.exe
• http://{BLOCKED}.{BLOCKED}.83.165/board/data/cd/JgFeQw.html

It saves the files it downloads using the following names:

• %System Root%\rundll32.exe - detected as TROJ_TALOC.NSW
• %System Root%\inst.exe - detected as TROJ_TALOC.NSW

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

It then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

Other Details

This Trojan does the following:

• It uses the dropped component hacking tool to download and execute the malicious file by starting the following process with parameters:
• cscript.exe {dropped component file} {target URL} {destination file}