TROJ_FAKEAV.YSWO
Trojan.FakeAV (Symantec); Rogue:Win32/FakeRean (Microsoft)
Windows
Threat Type: Trojan
Destructiveness: No
Encrypted:
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 executes then deletes itself afterward.
TECHNICAL DETAILS
84,480 bytes
EXE
Yes
08 Dec 2014
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 drops the following files:
- %AppDataLocal%\893686b8
- %Application Data%\893686b8
- %All Users Profile%\893686b8 (Windows Vista and higher versions)
- %All Users Profile%\Application Data\893686b8 (Versions lower than Windows Vista)
- %Application Data%\Microsoft\Windows\Templates\893686b8 (Windows Vista and higher versions)
- %User Profile%\Templates\893686b8 (Versions lower than Windows Vista)
(Note: %AppDataLocal% is the Application Data folder found in Local Settings, where it is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local 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.. %All Users Profile% is the All Users folder, where it usually is C:\Documents and Settings\All Users on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData 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.. %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)
It drops the following copies of itself into the affected system:
- %AppDataLocal%\{random alphanumeric characters}.exe
(Note: %AppDataLocal% is the Application Data folder found in Local Settings, where it is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local 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 then deletes itself afterward.
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\Run
qcgce2mrvjq91kk1e7pnbb19m52fx1956jc03il0h = "%AppDataLocal%\{random alphanumeric characters}.exe"
Other System Modifications
This Trojan deletes the following registry keys:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\wuauserv
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\WinDefend
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\wscsvc
Other Details
This Trojan connects to the following possibly malicious URL:
- http://{BLOCKED}737.com
- http://{BLOCKED}4se2.com
SOLUTION
9.700
11.330.03
08 Dec 2014
11.331.00
08 Dec 2014
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
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\Run
- qcgce2mrvjq91kk1e7pnbb19m52fx1956jc03il0h = "%AppDataLocal%\{random alphanumeric characters}.exe"
- qcgce2mrvjq91kk1e7pnbb19m52fx1956jc03il0h = "%AppDataLocal%\{random alphanumeric characters}.exe"
Step 5
Search and delete this file
- %AppDataLocal%\893686b8
- %Application Data%\893686b8
- %All Users Profile%\893686b8 (Windows Vista and higher versions)
- %All Users Profile%\Application Data\893686b8 (Versions lower than Windows Vista)
- %Application Data%\Microsoft\Windows\Templates\893686b8 (Windows Vista and higher versions)
- %User Profile%\Templates\893686b8 (Versions lower than Windows Vista)
Step 6
Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- wuauserv
- wuauserv
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services
- WinDefend
- WinDefend
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services
- wscsvc
- wscsvc
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_FAKEAV.YSWO. 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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