TROJ_CRYPTLOCK.JN
Win32/Filecoder.DI (ESET-NOD32), Ransom:Win32/Teerac.A (Microsoft), RDN/Ransom!ex (McAfee)
Windows
![](/vinfo/imgFiles/legend.jpg)
Threat Type: Trojan
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
Downloaded from the Internet
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.
It does not have any propagation routine.
It does not have any backdoor routine.
It connects to certain websites to send and receive information. However, as of this writing, the said sites are inaccessible.
TECHNICAL DETAILS
286,720 bytes
EXE
Yes
27 Apr 2015
Connects to URLs/IPs, Encrypts files
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.
Installation
This Trojan drops the following copies of itself into the affected system:
- %Windows%\{random 8 letters}.exe
- %User Startup%\system.pif
(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.. %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup.)
It drops the following file(s)/component(s):
- %All Users Profile%\Application Data\{random folder name}\03000000
- %All Users Profile%\Application Data\{random folder name}\04000000
- %All Users Profile%\Application Data\{random folder name}\05000000
- %All Users Profile%\Application Data\{random folder name}\00000000
- %All Users Profile%\Application Data\{random folder name}\01000000 ← encrypted copy of itself
- %All Users Profile%\Application Data\{random folder name}\02000000
(Note: %All Users Profile% is the All Users folder, where it usually is C:\Documents and Settings\All Users on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData on 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.)
It adds the following processes:
- explorer.exe
It creates the following folders:
- %All Users Profile%\Application Data\{random folder name}
(Note: %All Users Profile% is the All Users folder, where it usually is C:\Documents and Settings\All Users on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData on 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.)
It adds the following mutexes to ensure that only one of its copies runs at any one time:
- Global\{random}
It injects codes into the following process(es):
- created explorer.exe
Autostart Technique
This Trojan adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
{random letters} = "%Windows%\{random 8 letters}.exe"
Other System Modifications
This Trojan adds the following registry keys:
HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\PhishingFilter
It adds the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\PhishingFilter
EnabledV8 = 0
HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\PhishingFilter
EnabledV9 = 0
Propagation
This Trojan does not have any propagation routine.
Backdoor Routine
This Trojan does not have any backdoor routine.
Information Theft
This Trojan gathers the following data:
- Machine GUID
- Computer name
Other Details
This Trojan connects to the following website to send and receive information:
- https://{BLOCKED}ck.ru/topic.php
It encrypts files with the following extensions:
- avi
- wav
- mp3
- gif
- ico
- png
- bmp
- txt
- html
It renames encrypted files using the following names:
- {original file name and extension}.encrypted
However, as of this writing, the said sites are inaccessible.
NOTES:
This Trojan does not encrypt files with the following extensions:
- bat
- chm
- cmd
- dll
- exe
- ini
- lnk
- log
- msi
- scr
- sys
- tmp
- url
It deletes shadow copies by executing the following command:
vssadmin.exe Delete Shadows /All /Quiet
The malware will access the URL(s) to download its ransom notes.
It does not have rootkit capabilities.
It does not exploit any vulnerability.
SOLUTION
9.750
11.634.01
27 Apr 2015
11.635.00
28 Apr 2015
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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- {random letters} = "%Windows%\{random 8 letters}.exe"
- {random letters} = "%Windows%\{random 8 letters}.exe"
Step 5
Delete this registry key
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\Microsoft\Internet Explorer
- PhishingFilter
- PhishingFilter
Step 6
Search and delete this folder
- %All Users Profile%\Application Data\{random folder name}
Step 7
Search and delete these files
- %User Startup%\system.pif
Step 8
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_CRYPTLOCK.JN. 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 9
Scan your computer with your Trend Micro product to delete files detected as TROJ_CRYPTLOCK.JN. 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.
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