RANSOM_HIDDENTEARHOBOT.A
Ransom.HiddenTear (NORTON); Trojan:Win32/Dynamer!rfn (Microsoft)
Windows
![](/vinfo/imgFiles/legend.jpg)
Threat Type: Ransomware
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
This Ransomware arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
It drops files as ransom note.
TECHNICAL DETAILS
Arrival Details
This Ransomware arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
Ransomware Routine
This Ransomware avoids encrypting files with the following strings in their file name:
- HOW_TO_RECOVER_ENCRYPTEDFILES
- .hobot2good
It appends the following extension to the file name of the encrypted files:
- .hobot2good
It drops the following file(s) as ransom note:
- {folder of encrypted files}\HOW_TO_RECOVER_ENCRYPTEDFILES.txt
NOTES:
This ransomware shows the following window after execution:
![](https://documents.trendmicro.com/images/RANSOM_HIDDENTEARHOBOT_A1.jpg)
The hide button hides the window. The exit and delete buttons runs the following process to delete itself:
cmd.exe /C choice /C Y /N /D Y /T 3 & Del {malwarepath}
It the terminates.
The send key button generates new ID and password for encryption.
There are four text boxes listing folders to be encrypted. Default values of entries include:
- {all drive letters except C:\}
- C:\Users
- C:\ProgramData
- C:\ProgramFiles
- C:\ProgramFiles (x86)
The start button triggers encryption routine. Entries can be edited before triggering the start button. It triggers the exit and delete routine after encrypting all folders listed in all four text boxes.
It drops ransom note {folder of encrypted files}\HOW_TO_RECOVER_ENCRYPTEDFILES.txt that contains the following:
![](https://documents.trendmicro.com/images/RANSOM_HIDDENTEARHOBOT_A2.jpg)
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
Identify and terminate files detected as RANSOM_HIDDENTEARHOBOT.A
- Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
- If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
- If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.
Step 4
Search and delete these files
- {folder of encrypted files}\HOW_TO_RECOVER_ENCRYPTEDFILES.txt
Step 5
Scan your computer with your Trend Micro product to delete files detected as RANSOM_HIDDENTEARHOBOT.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
Restore encrypted files from backup.
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