W2KM_DLOADR.YYTCY
TrojanDownloader:O97M/Donoff (Microsoft); W97M.Downloader (Symantec); W97M/Downloader.cfx (McAfee)
Windows
![](/vinfo/imgFiles/legend.jpg)
Threat Type: Trojan
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This Trojan arrives as an attachment to email messages spammed by other malware/grayware or malicious users. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
It executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.
However, as of this writing, the said sites are inaccessible.
TECHNICAL DETAILS
78,982 bytes
DOC
No
21 Aug 2017
Arrival Details
This Trojan arrives as an attachment to email messages spammed by other malware/grayware or malicious users.
It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
Download Routine
This Trojan saves the files it downloads using the following names:
- %Application Data%\zYS.exe
(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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.)
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 connects to the following possibly malicious URL:
- http://{BLOCKED}rbyecasd.com/okas/cr.dat
- http://{BLOCKED}rbyecasd.com/s.php?id=cr
However, as of this writing, the said sites are inaccessible.
SOLUTION
9.850
13.610.08
22 Aug 2017
13.611.00
23 Aug 2017
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
- %Application Data%\zYS.exe
Step 4
Scan your computer with your Trend Micro product to delete files detected as W2KM_DLOADR.YYTCY. 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 5
Enable the macro virus protection in Microsoft Office Applications
Did this description help? Tell us how we did.