RANSOM_CRYPTESLA.SMJ5

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 deletes the initially executed copy of itself.

File Size: 622,592 bytes

File Type: EXE

Memory Resident: Yes

Initial Samples Received Date: 17 Jan 2016

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 and executes them:

%Application Data%\{random filename}.exe

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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 drops the following files:

%Desktop%\_H_e_l_p_RECOVER_INSTRUCTIONS.HTM
%Desktop%\_H_e_l_p_RECOVER_INSTRUCTIONS.png
%Desktop%\_H_e_l_p_RECOVER_INSTRUCTIONS.TXT
%User Profile%\_H_e_l_p_RECOVER_INSTRUCTIONS+{random characters}.html
%User Profile%\_H_e_l_p_RECOVER_INSTRUCTIONS+{random characters}.png
%User Profile%\_H_e_l_p_RECOVER_INSTRUCTIONS+{random characters}.txt
{Folders containg encrypted files}\_H_e_l_p_RECOVER_INSTRUCTIONS+{random characters}.html
{Folders containg encrypted files}\_H_e_l_p_RECOVER_INSTRUCTIONS+{random characters}.png
{Folders containg encrypted files}\_H_e_l_p_RECOVER_INSTRUCTIONS+{random characters}.txt
%My Documents%\recover_file_{random characters}.txt
(Note: %My Documents% is usually C:\Documents and Settings\{user name}\My Documents on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\Documents on Windows Vista and 7.)

(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.. %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)

Autostart Technique

This Trojan adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer\run
addon_v57 = "%Application Data%\{random filename}.exe"

Other System Modifications

This Trojan modifies the following file(s):

It encrypts files and appends the extension .mp3

Other Details

This Trojan connects to the following possibly malicious URL:

http://{BLOCKED}ricoop.net/tmp/mzsys.php
http://{BLOCKED}setvie.com/modules/mod_cmscore/mzsys.php
http://{BLOCKED}wohnung-walchensee-pur.de/tmp/mzsys.php
http://{BLOCKED}s.org/modules/mod_fxprev/libraries/mzsys.php
http://{BLOCKED}dehaan.be/modules/mod_cmscore/mzsys.php
http://{BLOCKED}drusgroup.com/components/com_acymailing/views/user/tmpl/mzsys.php

It deletes the initially executed copy of itself

Minimum Scan Engine: 9.800

FIRST VSAPI PATTERN FILE: 12.348.07

FIRST VSAPI PATTERN DATE: 17 Feb 2016

VSAPI OPR PATTERN File: 12.349.00

VSAPI OPR PATTERN Date: 18 Feb 2016

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

Scan your computer with your Trend Micro product and note files detected as RANSOM_CRYPTESLA.SMJ5

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

Delete this registry value

[ Learn More ]

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\Windows\CurrentVersion\Policies\Explorer\run
- addon_v57 = "%Application Data%\{random filename}.exe"

Step 5

Search and delete this file

[ Learn More ]

There may be some files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.

%Desktop%\_H_e_l_p_RECOVER_INSTRUCTIONS.HTM
%Desktop%\_H_e_l_p_RECOVER_INSTRUCTIONS.png
%Desktop%\_H_e_l_p_RECOVER_INSTRUCTIONS.TXT
%User Profile%\_H_e_l_p_RECOVER_INSTRUCTIONS+{random characters}.html
%User Profile%\_H_e_l_p_RECOVER_INSTRUCTIONS+{random characters}.png
%User Profile%\_H_e_l_p_RECOVER_INSTRUCTIONS+{random characters}.txt
{Folders containg encrypted files}\_H_e_l_p_RECOVER_INSTRUCTIONS+{random characters}.html
{Folders containg encrypted files}\_H_e_l_p_RECOVER_INSTRUCTIONS+{random characters}.png
{Folders containg encrypted files}\_H_e_l_p_RECOVER_INSTRUCTIONS+{random characters}.txt
%My Documents%\recover_file_{random characters}.txt

To manually delete a malware/grayware file from an affected system:

• For Windows 2000, Windows XP, and Windows Server 2003:

Right-click Start then click Search....
In the File name* input box, type the following:
%Desktop%\_H_e_l_p_RECOVER_INSTRUCTIONS.HTM
%Desktop%\_H_e_l_p_RECOVER_INSTRUCTIONS.png
%Desktop%\_H_e_l_p_RECOVER_INSTRUCTIONS.TXT
%User Profile%\_H_e_l_p_RECOVER_INSTRUCTIONS+{random characters}.html
%User Profile%\_H_e_l_p_RECOVER_INSTRUCTIONS+{random characters}.png
%User Profile%\_H_e_l_p_RECOVER_INSTRUCTIONS+{random characters}.txt
{Folders containg encrypted files}\_H_e_l_p_RECOVER_INSTRUCTIONS+{random characters}.html
{Folders containg encrypted files}\_H_e_l_p_RECOVER_INSTRUCTIONS+{random characters}.png
{Folders containg encrypted files}\_H_e_l_p_RECOVER_INSTRUCTIONS+{random characters}.txt
%My Documents%\recover_file_{random characters}.txt
In the Look In drop-down list, select My Computer then press Enter.
Once located, select the file then press SHIFT+DELETE to delete it.
*Note: The file name input box title varies depending on the Windows version (e.g. Search for files or folders named or All or part of the file name.).

• For Windows Vista, Windows 7, Windows Server 2008, Windows 8, Windows 8.1, and Windows Server 2012:

Open a Windows Explorer window.
- For Windows Vista, 7, and Server 2008 users, click Start>Computer.
- For Windows 8, 8.1, 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:
%Desktop%\_H_e_l_p_RECOVER_INSTRUCTIONS.HTM
%Desktop%\_H_e_l_p_RECOVER_INSTRUCTIONS.png
%Desktop%\_H_e_l_p_RECOVER_INSTRUCTIONS.TXT
%User Profile%\_H_e_l_p_RECOVER_INSTRUCTIONS+{random characters}.html
%User Profile%\_H_e_l_p_RECOVER_INSTRUCTIONS+{random characters}.png
%User Profile%\_H_e_l_p_RECOVER_INSTRUCTIONS+{random characters}.txt
{Folders containg encrypted files}\_H_e_l_p_RECOVER_INSTRUCTIONS+{random characters}.html
{Folders containg encrypted files}\_H_e_l_p_RECOVER_INSTRUCTIONS+{random characters}.png
{Folders containg encrypted files}\_H_e_l_p_RECOVER_INSTRUCTIONS+{random characters}.txt
%My Documents%\recover_file_{random characters}.txt
Once located, select the file then press SHIFT+DELETE to delete it.
*Note: Read the following Microsoft page if these steps do not work on Windows 7.

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as RANSOM_CRYPTESLA.SMJ5. 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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