Ransom.Win32.WANNACRY.COMS
Ransom:Win32/WannaCrypt.H (MICROSOFT), Trojan-Ransom.Win32.Wanna.m (KASPERSKY)
Windows
Threat Type: Ransomware
Destructiveness: No
Encrypted: No
In the wild: Yes
OVERVIEW
This Ransomware executes the dropped file(s). As a result, malicious routines of the dropped files are exhibited on the affected system.
TECHNICAL DETAILS
Arrival Details
This malware arrives via the following means:
Installation
This Ransomware drops the following files:
- %Windows%\qeriuwjhrf
(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)
It adds the following processes:
- %Windows%\tasksche.exe /i
- %User Temp%\mssecsvr.exe -m security
- %System%\sc.exe start w32time task_started
(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.. %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)
Autostart Technique
This Ransomware registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\mssecsvc2.1
Type = "16"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\mssecsvc2.1
Start = "2"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\mssecsvc2.1
ErrorControl = "1"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\mssecsvc2.1
ImagePath = "{initial malware file path} -m security"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\mssecsvc2.1
DisplayName = "Microsoft Security Center (2.1) Service"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\mssecsvc2.1
ObjectName = "LocalSystem"
It registers as a system service to ensure its automatic execution at every system startup by adding the following registry keys:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\mssecsvc2.1
It starts the following services:
- Service Name: mssecsvc2.1
Display Name: Microsoft Security Center (2.1) Service
Path to Executable: "{initial malware file path} -m security"
Dropping Routine
This Ransomware drops the following files:
- %Windows%\tasksche.exe ← detected as Ransom.Win32.WCRY.DAM
It executes the dropped file. As a result, malicious routines of the dropped file are exhibited on the affected system.
Download Routine
This Ransomware connects to the following URL(s) to download its component file(s):
- http://{BLOCKED}-smiles.com
Other Details
This Ransomware does the following:
- It connects to http://www.{BLOCKED}sodp9ifjaposdfjhgosurijfaewrwergwff.com/. It is initially used as a kill switch for infection. However, on this variant, it will still continue with its routine regardless of the connection.
- It scans the following to check for open port 445:
- Randomly-generated IP addresses over the internet
- If it finds a host on the internet with open port 445, it will attempt to exploit MS17-010 vulnerability to drop and execute a copy of itself to the remote host.
- It uses the following file path for its dropped copies on the remote hosts.
%Windows%\mssecsvc.exe - It checks for the presence of the file %Windows%\tasksche.exe. If the file exists, it will rename the file using the following name %Windows%\qeriuwjhrf.
- It executes %Windows%\tasksche.exe with /i parameter.
SOLUTION
Step 1
Trend Micro Predictive Machine Learning detects and blocks malware at the first sign of its existence, before it executes on your system. When enabled, your Trend Micro product detects this malware under the following machine learning name:
-
Troj.Win32.TRX.XXPE50FFF067
Step 2
Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 users must disable System Restore to allow full scanning of their computers.
Step 3
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 4
Remove malware/grayware files dropped/downloaded by Ransom.Win32.WANNACRY.COMS. (Note: Please skip this step if the threats listed below have already been removed.)
Step 5
Restart in Safe Mode
Step 6
Disable this malware service
- mssecsvc2.1
Step 7
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_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services
- mssecsvc2.1
- mssecsvc2.1
Step 8
Search and delete these files
- %Windows%\tasksche.exe
- %Windows%\mssecsvc.exe
- %Windows%\qeriuwjhrf
Step 9
Restart in normal mode and scan your computer with your Trend Micro product for files detected as Ransom.Win32.WANNACRY.COMS. 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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