Backdoor.JS.EVILAI.YXFH3
Windows
Threat Type: Backdoor
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
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 a website to send and receive information.
TECHNICAL DETAILS
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.
Backdoor Routine
This Backdoor connects to the following websites to send and receive information:
- https://pdf-tool.{BLOCKED}tes.ai/api/s3/new
- https://sdk.{BLOCKED}tes.ai/api/s3/config
- https://pdf-tool.{BLOCKED}tes.ai/api/s3/validate
- https://sdk.{BLOCKED}tes.ai/api/s3/options
- https://log.{BLOCKED}tes.ai/api/s3/event
- https://on.{BLOCKED}tes.ai/api/s3/ping
- https://{BLOCKED}tes.ai/api/s3/remove
Other Details
This Backdoor does the following:
- It executes the following backdoor commands:
- Read, write, delete, enumerate, or extract files.
- Read, write, or delete registry entries
- Download and execute files
- Enumerate processes
- Terminate processes
- Execute processes
- Execute arbitrary commands
- It can steal information from the following browsers:
- Wave Browser
- OneLaunch Browser
- Shift Browser
- It can steal the following information from browsers:
- Saved Credentials
- Browser History
- Cookies
It accepts the following parameters:
- --c and --cm missing → initiates installation
- --c=0 → skips main backdoor routine and runs GUI if the file %User Profile%\PDF Editor\resources\app\w-electron\bin\release\mode.data exists
- --cm=--cleanup → unregisters machine from the server and deletes created scheduled tasks
- --cm=--partialupdate → read and modify browser configurations, executed by PDFEditorScheduledTask every 24 hours
- --cm=--fullupdate → read and modify browser configurations, triggered via registry autorun or manual execution
- --cm=--enableupdate → adds the autorun key PDFEditorUpdater with --cm=--fullupdate command line argument
- --cm=--disableupdate → removes the autorun key PDFEditorUpdater
- --cm=--backupupdate → maintains command and control server connectivity
(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name} on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)
It adds the following scheduled tasks:
- Task Name: PDFEditorScheduledTask
Description: PDFEditorScheduledTask
Trigger: Once daily, every 1442 minutes
Action: "%AppDataLocal%\Programs\PDFEditor\PDF Editor.exe" --cm=--partialupdate - Task Name: PDFEditorUScheduledTask
Description: PDFEditorUScheduledTask
Action:: "%AppDataLocal%\Programs\PDFEditor\PDF Editor.exe" --cm=--backupupdate
(Note: %AppDataLocal% is the Local Application Data folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)
SOLUTION
Step 1
Restart in Safe Mode
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
Deleting Scheduled Tasks while in Safe Mode
- Still in safe mode, the following {Task Name}-{Task to be run} listed should be used in the steps identified below:
- Task Name: PDFEditorScheduledTask
- Task to be run: %AppDataLocal%\Programs\PDFEditor\PDF Editor.exe --cm=--partialupdate
- Task Name: PDFEditorUScheduledTask
- Task to be run: %AppDataLocal%\Programs\PDFEditor\PDF Editor.exe --cm=--backupupdate
- For Windows 7 and Server 2008 (R2) users, click Start>Computer.
- For Windows 8, 8.1, 10, and Server 2012 users, right-click on the lower left corner of the screen, then click File Explorer.
- In the Search Computer/This PC input box, type:
- %System%\Tasks\{Task Name}
- Once located, select the file then press SHIFT+DELETE to delete it.
- Open Registry Editor. To do this:
- For Windows 7 and Server 2008 (R2) users, click the Start button, type regedit in the Search input field, and press Enter.
- For Windows 8, 8.1, 10, and Server 2012 (R2) users, right-click on the lower left corner of the screen, click Run, type regedit in the text box
- In the left panel of the Registry Editor window, double-click the following:
- HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Windows NT>CurrentVersion>Schedule>TaskCache>Tree>{Task Name}
- Locate the created entry and take note of the registry value's data:
- ID={Task Data}
- After taking note of the data, delete the registry key:
- HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Windows NT>CurrentVersion>Schedule>TaskCache>Tree>{Task Name}
- In the left panel of the Registry Editor window, double-click the following:
- HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Windows NT>CurrentVersion>Schedule>TaskCache>Tasks
- Still in the left panel, locate and delete the registry key with the same name as the located Task Data in step #6:
- ={Task Data}
- Close Registry Editor.
Step 5
Scan your computer with your Trend Micro product to delete files detected as Backdoor.JS.EVILAI.YXFH3. 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 the following Trend Micro Support pages for more information:
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