VBS_OLEAR.C
VirTool:VBS/Obfuscator.H, Exploit:VBS/CVE-2014-6332 (Microsoft)
Windows
Threat Type: Trojan
Destructiveness: No
Encrypted: Yes
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 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.
TECHNICAL DETAILS
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
(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:
Download Routine
This Trojan connects to the following URL(s) to download its component file(s):
- http://{BLOCKED}eong.com/files/oms.exe
It saves the files it downloads using the following names:
- %System Root%\rundll32.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 hacking tool Uninstall.Vbs to download and execute the malicious file by starting the following process with parameters:
- cscript.exe %User Temp%\Uninstall.Vbs {target URL} {destination file}
(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.)
NOTES:
It does not have rootkit capabilities.
SOLUTION
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
Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.
Step 3
Remove malware/grayware files dropped/downloaded by VBS_OLEAR.C. (Note: Please skip this step if the threats listed below have already been removed.)
- HKTL_DLOADER.C
- TROJ_TALOC.NSW
Step 4
Close all opened browser windows
Step 5
Scan your computer with your Trend Micro product to delete files detected as VBS_OLEAR.C. 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
Download and apply these security patches Refrain from using these products until the appropriate patches have been installed. Trend Micro advises users to download critical patches upon release by vendors.
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