RANSOM_LOCKY.THJ
TrojanDownloader:JS/Locky!rfn(Microsoft), Trojan-Ransom.Locky(Ikarus), Win32/Kryptik.ESGK(ESET)
Windows
Threat Type: Trojan
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
However, as of this writing, the said sites are inaccessible. It is capable of encrypting files in the affected system.
TECHNICAL DETAILS
Arrival Details
This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
Other System Modifications
This Trojan adds the following registry keys:
HKEY_CURRENT_USER\Software\{random characters}
Dropping Routine
This Trojan drops the following files:
- %Desktop%\_HELP_instructions.txt
- %Desktop%\_HELP_instructions.bmp
- {Folders containing encrypted files}\_HELP_instructions.txt
(Note: %Desktop% is the desktop folder, where it usually is C:\Documents and Settings\{user name}\Desktop in Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\Desktop in Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)
Other Details
This Trojan connects to the following possibly malicious URL:
- http://{BLOCKED}.{BLOCKED}.187.228/main.php
- http://{BLOCKED}.{BLOCKED}.44.39/main.php
- http://{BLOCKED}.{BLOCKED}.209.123/main.php
- http://{BLOCKED}.{BLOCKED}.218.158/main.php
It renames encrypted files using the following names:
- {random string}.locky
However, as of this writing, the said sites are inaccessible.
It is capable of encrypting files in the affected system.
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
Search and delete these files
- %Desktop%\_HELP_instructions.txt
- %Desktop%\_HELP_instructions.bmp
- {Folders containing encrypted files}\_HELP_instructions.txt
Step 5
Restart in normal mode and scan your computer with your Trend Micro product for files detected as RANSOM_LOCKY.THJ. 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
The following created files/folders/registry keys/registry entries cannot be identified by the user since there are no reference values in the created key. The only way it can be identified is by comparing the present system information with a backup. Note that the said components do not have to be deleted since it won't be harmful to the system.
- In HKEY_CURRENT_USER\Software\{random characters}
- = ""
- = ""
Step 7
Restore encrypted files from backup.
Step 8
Scan your computer with your Trend Micro product to delete files detected as RANSOM_LOCKY.THJ. 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.
Did this description help? Tell us how we did.