RANSOM_GANDCRAB.THHOFAH
VirTool:Win32/VBInject (Microsoft), Trojan-Ransom.Win32.GandCrypt.dkl (Kaspersky)
Windows
Threat Type: Ransomware
Destructiveness: No
Encrypted:
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 deletes itself after execution. It is capable of encrypting files in the affected system.
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.
Installation
This Ransomware drops the following files:
- {Encrypted File Directory}\{GUID}.lock =>{Deleted after encryption in the directory}
Other System Modifications
This Ransomware adds the following registry entries:
HKEY_CURRENT_USER\Software\keys_data\
data
private = {key}
HKEY_CURRENT_USER\Software\keys_data\
data
public = {key}
Other Details
This Ransomware connects to the following possibly malicious URL:
- http://www.{BLOCKED}egrise.eu/
- http://www.{BLOCKED}egrise.eu/wp-content/tmp/seseda.bmp
- http://www.{BLOCKED}g.com/
- http://www.{BLOCKED}g.com/content/imgs/zuesdeme.gif
- http://{BLOCKED}photo.ru/
- http://{BLOCKED}photo.ru/includes/imgs/imthth.gif
- http://{BLOCKED}mpany.ru/
- http://{BLOCKED}mpany.ru/wp-content/tmp/fukekeamth.jpg
- http://www.{BLOCKED}undation.gm/
- http://www.{BLOCKED}undation.gm/content/pics/sethseth.jpg
- http://www.{BLOCKED}tfunnelblueprint.com/
- http://www.{BLOCKED}tfunnelblueprint.com/data/pics/ruzu.bmp
- http://www.{BLOCKED}ear.com/
- http://www.{BLOCKED}ear.com/data/graphic/sokerumefu.jpg
- http://{BLOCKED}da74.ru/
- http://{BLOCKED}da74.ru/content/tmp/soheheso.png
- http://{BLOCKED}t.net/
- http://{BLOCKED}t.net/uploads/tmp/kekamo.gif
- http://{BLOCKED}obabyphotographyseattle.com/
- http://{BLOCKED}obabyphotographyseattle.com/data/imgs/rufuth.jpg
- http://{BLOCKED}m.be/
- http://{BLOCKED}m.be/news/graphic/hedemede.bmp
- http://{BLOCKED}owradio.com/
- http://{BLOCKED}owradio.com/news/image/ruse.bmp
- http://{BLOCKED}emi.com/
- http://{BLOCKED}emi.com/uploads/pics/sohemoam.bmp
- http://www.{BLOCKED}v.hu/
- http://www.{BLOCKED}v.hu/news/pics/sokase.bmp
- http://www.{BLOCKED}d.cz/
- http://www.{BLOCKED}d.cz/data/imgs/eskaamheamme.jpg
- http://{BLOCKED}n.cn/
- http://{BLOCKED}n.cn/data/imgs/damehememo.png
- http://{BLOCKED}d.website/
- http://{BLOCKED}d.website/wp-content/graphic/zuesmo.gif
- http://{BLOCKED}inen.com/
- http://{BLOCKED}inen.com/content/image/keamda.png
It deletes itself after execution.
It is capable of encrypting files in the affected system.
Ransomware Routine
This Ransomware appends the following extension to the file name of the encrypted files:
- .KRAB
It drops the following file(s) as ransom note:
- {Encypted File Directory}\KRAB-DECRYPT.txt
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
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_CURRENT_USER\SOFTWARE\keys_data\data
- private = {key}
- private = {key}
- In HKEY_CURRENT_USER\SOFTWARE\keys_data\data
- public = {key}
- public = {key}
Step 5
Search and delete these files
- {Encrypted Folder}\KRAB-DECRYPT.txt
- {Encrypted File Directory}\{GUID}.lock
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as RANSOM_GANDCRAB.THHOFAH. 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 7
Restore encrypted files from backup.
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