TROJ_CRYPWALL.JV

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.

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:

• %System Root%\{random 8 characters}\{random 8 characters}.exe
• %Application Data%\{random 8 characters}.exe
• %User Startup%\{random 8 characters}.exe

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.. %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.. %User Startup% is the current user's Startup folder, which is usually C:\Documents and Settings\{user}\Start Menu\Programs\Startup on Windows 2000 and XP, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows Vista, 7, and 8.)

It drops the following files:

• %Desktop%\HELP_DECRYPT.HTML
• %Desktop%\HELP_DECRYPT.PNG
• %Desktop%\HELP_DECRYPT.TXT
• %Desktop%\HELP_DECRYPT.URL
• %User Startup%\HELP_DECRYPT.HTML
• %User Startup%\HELP_DECRYPT.PNG
• %User Startup%\HELP_DECRYPT.TXT
• %User Startup%\HELP_DECRYPT.URL

(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 Startup% is the current user's Startup folder, which is usually C:\Documents and Settings\{user}\Start Menu\Programs\Startup on Windows 2000 and XP, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows Vista, 7, and 8.)

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\Run
{random 7 characters} = "%System Root%\{random 8 characters}\{random 8 characters}.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{random 8 characters} = "%Application Data%\{random 8 characters}.exe"

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\{UID}

It adds the following registry entries:

HKEY_CURRENT_USER\Software\{UID}
{random 2 characters} = "{RSA PUBLIC KEY} "

HKEY_CURRENT_USER\Software\{UID}
{random 2 characters} = "{contents of HELP_DECRYPT.TXT}"

HKEY_CURRENT_USER\Software\{UID}
{random 2 characters} = "{contents of HELP_DECRYPT.HTML}"

HKEY_CURRENT_USER\Software\{UID}
{random 2 characters} = "{contents of HELP_DECRYPT.URL}"

HKEY_CURRENT_USER\Software\{UID}\
{random key}
{Path and file of encrypted file} = "{hex values}"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\ERSvc
Start = "4"

(Note: The default value data of the said registry entry is 2.)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\wscsvc
Start = "4"

(Note: The default value data of the said registry entry is 2.)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\BITS
Start = "4"

(Note: The default value data of the said registry entry is 2.)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\wuauserv
Start = "4"

(Note: The default value data of the said registry entry is 2.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\SystemRestore
DisableSR = "1"

(Note: The default value data of the said registry entry is 0.)

Other Details

This Trojan connects to the following possibly malicious URL:

• http://{BLOCKED}hestatemanagement.com/m/images/1.php
• http://{BLOCKED}lesdelsur.com/wp-includes/js/jcrop/2.php
• http://{BLOCKED}lesdelsur.com/wp-includes/js/jcrop/3.php
• http://{BLOCKED}lmarijuanamiamiflorida.com/4.php
• http://{BLOCKED}rphk.com/js-js/5.php
• http://{BLOCKED}terholmeproject.co.uk/js-js/1.php
• http://{BLOCKED}1morrow.com/wp-content/uploads/2013/12/2.php
• http://{BLOCKED}ngcareers.co.uk/images/prettyPhoto/light_square/4.php
• http://{BLOCKED}alizaciondigital.com/new/wp-includes/js/jcrop/5.php
• http://{BLOCKED}gonzalez.com/compras/image/data/1.php
• http://{BLOCKED}ah.com/images/Image/2.php
• http://{BLOCKED}ky.com/pdf/3.php
• http://{BLOCKED}otn.com/4.php
• http://{BLOCKED}ale.com/ilario_bordoni/assets/images/1.php
• http://{BLOCKED}oymenarguez.com/wp-content/plugins/js_composer/assets/css/lib/vc-linecons/fonts/2.php
• http://{BLOCKED}elli.it/wp-content/plugins/wordpress-seo/vendor/composer/installers/tests/Composer/3.php
• http://{BLOCKED}lendargirls.com/wp-content/plugins/jetpack/modules/publicize/assets/rtl/4.php
• http://{BLOCKED}lk.info/Wp/wp-content/plugins/wp-wizard-cloak/static/js/jquery/farbtastic/5.php
• http://{BLOCKED}ne365.com/heelziggler.com/wp-content/plugins/siteorigin-panels/widgets/widgets/call-to-action/presets/1.php
• http://{BLOCKED}lshobbycenter.be/components/com_jce/editor/tiny_mce/plugins/mediamanager/classes/getid3/2.php
• http://{BLOCKED}icus.com/wp-content/uploads/gravity_forms/6-55cd98d82aec1ece039f3a32332929d1/tmp/3.php
• http://{BLOCKED}r-modellage.de/phpSitemapNG/inc/gsgxml/4.php SitemapNG/inc/gsgxml/4.php -->
• http://{BLOCKED}osea.net/wp-content/plugins/wordpress-seo/vendor/composer/installers/tests/Composer/5.php
• http://{BLOCKED}2.com/wp-content/plugins/iphorm-form-builder/js/jqueryui/themes/blitzer/images/1.php
• http://{BLOCKED}orldtours.in/js/2.php
• http://{BLOCKED}tertime.com/wp-content/themes/blogoma/inc/blogoma-admin/options/validation/str_replace/3.php
• http://{BLOCKED}id.com/wp-content/themes/point/options/fields/radio/4.php
• http://{BLOCKED}ectric.com.au/wp-includes/js/tinymce/skins/wordpress/images/1.php
• http://{BLOCKED}no.com/flamingo/wp-content/plugins/jetpack/modules/shortcodes/css/rtl/2.php
• http://{BLOCKED}eative.com/cgi-bin/3.php
• http://{BLOCKED}atee.com/wp-includes/css/ap1.php
• http://{BLOCKED}ngcareers.co.uk/images/prettyPhoto/light_square/ap1.php
• http://{BLOCKED}o.com/wp-admin/network/ap5.php
• http://{BLOCKED}albatterycase.com/wp-admin/js/ap4.php
• http://{BLOCKED}cepts.net/wp-content/plugins/indonez-shortcodes/js/ap3.php
• http://{BLOCKED}t.com/wp-includes/fonts/ap5.php
• http://{BLOCKED}rsomaha.net/wp-includes/Text/Diff/Renderer/ap3.php
• http://{BLOCKED}urityservices.com/wp-admin/images/ap2.php
• http://{BLOCKED}mission.org/wp-includes/theme-compat/ap5.php
• http://{BLOCKED}ercables.com/wp-admin/user/ap1.php
• http://{BLOCKED}ainjurycenters.com/backups_georgia/back%2007102014/ap4.php
• http://{BLOCKED}vap.com/mtqzpa/templates/ap5.php
• http://{BLOCKED}hosp.com/hagg2013/wp-includes/theme-compat/ap3.php
• http://{BLOCKED}vac.ca/ap1.php

It deletes the initially executed copy of itself

NOTES:

It encrypts files with certain file extensions.

It appends random extensions to the file names of the encrypted files

It drops HELP_DECRYPT.HTML, HELP_DECRYPT.PNG, HELP_DECRYPT.TXT, and HELP_DECRYPT.URL to all the folders where files are encrypted.

It connects to the following non-malicious URLs:

• http://ip-addr.es