Backdoor.Win32.FLAWEDGRACE.AC
Backdoor:Win32/GraceWire.D!dha(MICROSOFT),
Windows
Threat Type: Backdoor
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
Dropped by other malware, Downloaded from the Internet
This Backdoor 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 commands from a remote malicious user, effectively compromising the affected system.
TECHNICAL DETAILS
692,136 bytes
Yes
20 Feb 2019
Connects to URLs/IPs, Steals information
Arrival Details
This Backdoor 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 Backdoor drops the following files:
- %All Users Profile%\{System Volume Hash}.dat -> run with admin privileges
- %All Users Profile%\{System Volume Hash}.bin -> run with admin privileges
- %ProgramData%\{System Volume Hash}.bin -> run without admin privileges
- %ProgramData%\{System Volume Hash}.dat -> run without admin privileges
(Note: %All Users Profile% is the common user's profile folder, which is usually C:\Documents and Settings\All Users on Windows 2000, XP, and Server 2003, or C:\ProgramData on Windows Vista, 7, and 8. . %ProgramData% is a version of the Program Files folder where any user on a multi-user computer can make changes to programs. This contains application data for all users. This is usually C:\ProgramData in Windows Vista, 7, and 8.)
It adds the following processes:
- cmd /C net localgroup
Other System Modifications
This Backdoor adds the following registry entries as part of its installation routine:
HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
SoftwareSASGeneration = "1"
Backdoor Routine
This Backdoor executes the following commands from a remote malicious user:
- Downloads File (target_download)
- Load and Unload Modules (target_module_load, target_module_load_external, target_module_unload)
- Get Passwords (target_passwords)
- RDP Session (target_rdp)
- Reboot system (target_reboot)
- Delete Files (target_remove)
- Run Scripts (target_script)
- List of Servers (target_servers)
- Update Version (target_update)
- Upload File (target_upload)
- Gather system information (desktop_stat)
- Force shutdown (destroy_os)
It connects to the following URL(s) to send and receive commands from a remote malicious user:
- {BLOCKED}.{BLOCKED}.16.228:443
Information Theft
This Backdoor gathers the following data:
- Computer Name
- User's Credentials (password)
- OS Version
- Architecture
- Domain Name
- Username
- Admin priveleges (User Account Control)
- Boot
- Locale
- Antivirus Product Name obtained via WMI query
- Malware installed time
- Malware version
- Local IP
Other Details
This Backdoor does the following:
- This Backdoor accepts the following parameters:
- -i (process ID)
- -sn (service name)
- -p (pipe)
- -m (module)
- This Backdoor find IP address using the following process:
- cmd /C ipconfig | findstr /R /%System Root%"IPv4 Address"
(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)
SOLUTION
9.850
14.868.03
13 Mar 2019
14.869.00
14 Mar 2019
Step 1
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 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_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\System
- SoftwareSASGeneration = "1"
- SoftwareSASGeneration = "1"
Step 5
Search and delete this file
- %All Users Profile%\{System Volume Hash}.dat
- %All Users Profile%\{System Volume Hash}.bin
- %ProgramData%\{System Volume Hash}.bin
- %ProgramData%\{System Volume Hash}.dat
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as Backdoor.Win32.FLAWEDGRACE.AC. 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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