PE_MEWSEI.A-O
W32/MewsSpy.Q!tr (Fortinet), Virus:Win32/Mewsei.A (Microsoft)
Windows
![](/vinfo/imgFiles/legend.jpg)
Threat Type: File infector
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This file infector 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 file infector 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 file infector drops the following copies of itself into the affected system:
- %Application Data%\{random folder 1}\{random 9}.exe
- %AllUsersProfile%\Application Data\{random folder 1}\{random 9}.exe
- %Application Data%\{random folder 1}\{random 9}.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 drops the following file(s)/component(s):
- %Application Data%\{random folder 1}\{random 1}.dat
- %Application Data%\{random folder 1}\{random folder 2}\{random 2}.mui
- %Application Data%\{random folder 1}\{random folder 2}\{random 3}.sys
- %Application Data%\{random folder 1}\{random folder 2}\{random 4}.drv
- %Application Data%\{random folder 1}\{random folder 2}\{random 5}.ocx
- %Application Data%\{random folder 1}\{random folder 2}\{random 6}.dat
- %Application Data%\{random folder 1}\{random folder 2}\{random 7}.cat
- %Application Data%\{random folder 1}\{random 8}.dat
- %AllUsersProfile%\Application Data\{random folder 1}\{random 10}.mui
- %Application Data%\{random folder 1}\{random folder 3}\{random folder 4}\{random 11}.sys
- %Application Data%\{random folder 1}\{random folder 3}\{random folder 4}\{random 12}.drv
- %AllUsersProfile%\Application Data\{random folder 1}\{random 13}.bin
- %Application Data%\{random folder 1}\{random folder 3}\{random folder 4}\{random 14}.drv
- %Application Data%\{random folder 1}\{random folder 3}\{random 15}.bin
- %Application Data%\{random folder 1}\{random folder 3}\{random folder 5}\{random 16}.dat
- %Application Data%\{random folder 1}\{random folder 3}\{random folder 5}\{random 17}.cat
- %Application Data%\{random folder 1}\{random folder 3}\{random folder 5}\{random 18}.drv
- %Application Data%\{random folder 1}\{random folder 3}\{random folder 5}\{random 19}.cat
- %Application Data%\{random folder 1}\{random folder 3}\{random folder 6}\{random 20}.dat
- %Application Data%\{random folder 1}\{random folder 3}\{random 21}.drv
- %AllUsersProfile%\Application Data\{random folder 1}\{random folder 3}\{random 22}.dmp
- %Application Data%\{random folder 1}\{random 23}.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 creates the following folders:
- %Application Data%\{random folder}
- %AllUsersProfile%\{random folder}
(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.)
Other System Modifications
This file infector adds the following registry keys:
HKEY_CURRENT_USER\Software\Policies\
Microsoft\Windows\AppCompat
HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows\AppCompat
HKEY_USERS\{SID}\{random key}
It adds the following registry entries:
HKEY_USERS\{SID}\{random key}\
shell\open\command
(Default) = "%Application Data%\{random folder}\[random filename 2}.exe" /START "%1" %*
HKEY_USERS\{SID}\{random key}\
shell\open\command
IsolatedCommand = "%Application Data%\{random folder}\[random filename 2}.exe" /START "%1" %*
HKEY_USERS\{SID}\{random key}\
shell\runas\command
(Default) = "%Application Data%\{random folder}\[random filename 2}.exe" /RUNAS /START "%1" %*
HKEY_USERS\{SID}\{random key}\
shell\runas\command
IsolatedCommand = "%Application Data%\{random folder}\[random filename 2}.exe" /RUNAS /START "%1" %*
HKEY_CURRENT_USER\Software\Policies\
Microsoft\Windows\AppCompat
DisablePCA = "1"
HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows\AppCompat
DisablePCA = "1"
Other Details
This file infector connects to the following URL(s) to get the affected system's IP address:
- http://icanhazip.com/
It connects to the following possibly malicious URL:
- http://{random characters}.ddns.net/si.php?xu={data}
NOTES:
This malware infects files in all removable and network drives to propagate to other systems connected in a network.
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
Restart in Safe Mode
Step 4
Search and delete these folders
- %Application Data%\{random folder}
- %AllUsersProfile%\{random folder}
Step 5
Delete this registry key
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\Policies\Microsoft\Windows
- AppCompat
- AppCompat
- In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows
- AppCompat
- AppCompat
- In HKEY_USERS\{SID}
- {random key}
- {random key}
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as PE_MEWSEI.A-O. 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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