TROJ_DOFOIL.YUYIF
Trojan:Win32/Bagsu!rfn (Microsoft)
Windows
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 executes the dropped file(s). As a result, malicious routines of the dropped files are exhibited on the affected system.
TECHNICAL DETAILS
266,947 bytes
EXE
Yes
12 Jan 2016
Arrival Details
This Trojan arrives as an attachment to email messages spammed by other malware/grayware or malicious users.
Installation
This Trojan drops the following files:
- %User Temp%\pic_invoice.gif - fake invoice opened by malware in user's default browser
(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.)
Autostart Technique
This Trojan adds the following registry entries to enable its automatic execution at every system startup:
HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
Explorer\Run
{random value name} = "%Application Data%\{random 8 characters}\{random 8 characters}.exe"
Dropping Routine
This Trojan drops the following files:
- %User Temp%\jap100.exe
- %Application Data%\{random 8 characters}\{random 8 characters}.exe - copy of jap100.exe
(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.. %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 executes the dropped file(s). As a result, malicious routines of the dropped files are exhibited on the affected system.
SOLUTION
9.800
12.268.05
12 Jan 2016
12.267.00
13 Jan 2016
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_DOFOIL.YUYIF
Step 3
Restart in Safe Mode
Step 4
Delete this registry value
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 HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\Explorer\Run
- {random value name} = "%Application Data%\{random 8 characters}\{random 8 characters}.exe"
- {random value name} = "%Application Data%\{random 8 characters}\{random 8 characters}.exe"
Step 5
Search and delete this file
- %User Temp%\pic_invoice.gif
- %User Temp%\jap100.exe
- %Application Data%\{random 8 characters}\{random 8 characters}.exe
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_DOFOIL.YUYIF. 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.
Did this description help? Tell us how we did.