W2KM_DLOADR.YYSTA
TrojanDownloader:O97M/Donoff (Microsoft); VBA/TrojanDownloader.Agent.BTG (ESET); W97M.Downloader (Symantec);
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.
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.
Installation
This Trojan adds the following processes:
- powershell.exe
Download Routine
This Trojan connects to the following website(s) to download and execute a malicious file:
- http://{BLOCKED}allday.com/data/office
It saves the files it downloads using the following names:
- %User Temp%\{random file name}.tmp
(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 connects the following URL to download data related to GeoIP:
https://www.{BLOCKED}d.com/en/locate-my-ip-address
The downloaded data should contain OCEANIA.
The downloaded data should not contain any of the following strings:
It does not run if the Recent Files Count is less than 3.
It does not run if the application tasks count is less than 50.
It terminates itself if any of the following processes were found running in the system:
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
Search and delete these files
- %User Temp%\{random file name}.tmp
Step 4
Scan your computer with your Trend Micro product to delete files detected as W2KM_DLOADR.YYSTA. 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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