This is the Trend Micro detection for the backdoor installed by the PowerTrick post-exploitation toolkit believed to be developed by creators of Trickbot.
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 connects to certain websites to send and receive 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 and executes the following files:
- {Malware Path}\{Malware Name}.exe:$FILE → contains {Malware Path}\{Malware Name}.exe
- {Malware Path}\{Malware Name}.exe:$GUID → contains /anchor_dns/{Workstation Name}_{Windows Version}.<{32-character long client ID}>/[0-1]/{Content}\xb[0-9]
- {Malware Path}\{Malware Name}.exe:$TASK → contains "{string1} autoupdate#{5 Random Numbers}.xml"
- {string1} can be any of the folders found on %Application Data%
- "{string1} autoupdate#{5 Random Numbers}".xml → a task scheduler that executes the malware sample with parameter -u every fifteenth minute
(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)
Other Details
This Backdoor connects to the following website to send and receive information:
- {Obfuscated Message Type + UUID}{Content}.{BLOCKED}ivo.com
- where Message Type can be any of the following:
- Type 0 (Sending of Data)
- Type 1 (Preparation for receival of Data)
- Type 2 (Receiving of Data)
It adds the following scheduled tasks:
- Task Name: {string1} autoupdate#{5 Random Numbers}
- Trigger: At log on of any user; At 8:38PM every day for every 15 minutes for a duration of 1 day. Both trigger expires at 12/31/2028 11:59:59PM
- Action: Starts a program → %User Temp%\{Malware Name}.exe -u
- -u will perform standard communication with C2 server using subdomain names to send data and resolved IPs as receival of data
(Note: %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).)
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
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To restart in Safe Mode:
• For Windows 7 and Windows Server 2008 (R2) users
- Restart your computer.
- Press F8 after the Power-On Self Test (POST) routine is done. If the Advanced Boot Options menu does not appear, try restarting and then pressing F8 several times after the POST screen is displayed.
- On the Advanced Boot Options menu, use the arrow keys to select the Safe Mode option, and then press Enter.
• For Windows 8, Windows 8.1, and Windows Server 2012 users
- Access the Charms bar by moving your mouse pointer to the upper right corner of the screen.
- Move your mouse pointer down and click Settings>Change your PC Settings.
- In the left panel, click General.
- In the right panel, scroll down to the bottom to find the Advanced startup section, then click the Restart now button and wait for the system to restart.
- In the Advanced Startup menu, click Troubleshoot>Advanced Options>Startup Settings>Restart and wait for the system to restart.
- In the Startup Settings menu, press 4 to enable safe mode.
• For Windows 10 users
- Press Windows logo key + I on your keyboard to open Settings. If that doesn't work, select the Start button, then select Settings.
- Select Update & Security > Recovery.
- Under Advanced startup, select Restart now.
- After your PC restarts to the Choose an option screen, select Troubleshoot > Advcanced options > Startup settings > Restart.
- After your PC restarts, you'll see a list og options. Select 4 or press F4 to start your PC in Safe Mode.
Step 4
Search and delete this file
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There may be some files that are hidden. Please make sure you check the
Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
- %User Temp%\{Malware Name}.exe
- {Malware Path}\{Malware Name}\{Malware Name}:$FILE
- {Malware Path}\{Malware Name}\{Malware Name}:$GUID
- {Malware Path}\{Malware Name}\{Malware Name}:$TASK
- "{string1} autoupdate#{5 Random Numbers}".xml
To manually delete a malware/grayware file from an affected system:
•For Windows 7, Windows Server 2008 (R2), Windows 8, Windows 8.1, Windows 10, and Windows Server 2012 (R2):
- Open a Windows Explorer window.
- For Windows 7 and Server 2008 (R2) users, click Start>Computer.
- For Windows 8, 8.1, 10, and Server 2012 (R2) users, right-click on the lower-left corner of the screen,then click File Explorer.
- In the Search Computer/This PC input box, type:
- %User Temp%\{Malware Name}.exe
- {Malware Path}\{Malware Name}\{Malware Name}:$FILE
- {Malware Path}\{Malware Name}\{Malware Name}:$GUID
- {Malware Path}\{Malware Name}\{Malware Name}:$TASK
- "{string1} autoupdate#{5 Random Numbers}".xml
- Once located, select the file then press SHIFT+DELETE to delete it.
*Note: Read the following Microsoft page if these steps do not work on Windows 7 and Windows Server 2008 (R2).
Step 5
Restart in normal mode and scan your computer with your Trend Micro product for files detected as Backdoor.Win64.ANCHOR.A. 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.
Step 6
- Open a command prompt.
- For Windows 7 users, click Start, enter CMD in the Find input field, and press Enter.
- In the CMD console, enter the following:
ATTRIB [+R | -R] [+A | -A ] [+S | -S] [+H | -H] [+I | -I] [drive:][path][filename] [/S [/D] [/L]]
Where:
+ Activates an attribute
- Disables an attribute
R Read-only file attribute
A Archive file attribute
S System file attribute
H Hidden file attribute
I Indexed file attribute without content
[drive:][path][filename]
Specifies one or more files in the current folder and all its subfolders
/S Processes the corresponding files in the current folder and all its subfolders
/D Process folders
/L Act on the attributes of the symbolic link instrad of the target of the symbolic link
Example:
To make all files and folders (including subfolders visible in drive D:
ATTRIB –H D:\* /S /D
- Repeat the step above for folders and files from other drives or directories.
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