TROJ_CRYPWALL.CG

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 itself after execution.

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 files:

• {folders in drives}:\HELP_DECRYPT.HTML
• {folders in drives}:\HELP_DECRYPT.PNG
• {folders in drives}:\HELP_DECRYPT.TXT
• {folders in drives}:\HELP_DECRYPT.URL

It drops the following copies of itself into the affected system:

• %System Root%\{random}\{random}.exe
• %Application Data%\{random}.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.)

It creates the following folders:

• %System Root%\5fa97489

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

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} = "%System Root%\{random}\{random}.exe"

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

It drops the following file(s) in the Windows User Startup folder to enable its automatic execution at every system startup:

• %User Startup%\{random}.exe - copy of itself

(Note: %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.)

Other System Modifications

This Trojan modifies the following registry entries:

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

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

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\BITS
Start = "3"

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

Other Details

This Trojan connects to the following possibly malicious URL:

• {BLOCKED}inaschoice.com/wp-content/uploads/2015/03/update-edf1e5b53b49cbcabba91da03045b984/tmp/e3.php
• {BLOCKED}hevent.com/wp-content/plugins/e5.php
• {BLOCKED}419.com/wp-admin/js/e1.php
• {BLOCKED}nt.com/wp-includes/pomo/e2.php
• {BLOCKED}fly.net/wp-content/themes/akita/framework/frontend/assets/images/e1.php
• {BLOCKED}b.com/wp-includes/SimplePie/Cache/e5.php
• {BLOCKED}e.org/wp-content/plugins/e2.php
• {BLOCKED}shsharma.com/wp-includes/pomo/e4.php
• {BLOCKED}urada.com/hello/wp-admin/css/colors/sunrise/e3.php
• {BLOCKED}ingsuk.com/wp-includes/certificates/e2.php
• {BLOCKED}rstar.com/wp-content/plugins/e5.php
• {BLOCKED}dj.net/wp-includes/js/tinymce/plugins/e2.php
• {BLOCKED}bond.com/wp-includes/js/tinymce/plugins/e1.php
• {BLOCKED}rianway.com/wp-includes/js/tinymce/plugins/e3.php
• {BLOCKED}ougharchitecture.com/wp-content/uploads/2014/04/e2.php
• {BLOCKED}ougharchitecture.com/wp-content/uploads/2014/04/e2.php?
• {BLOCKED}nline.com/wp-includes/js/tinymce/themes/advanced/skins/highcontrast/e4.php
• {BLOCKED}nline.com/wp-includes/js/tinymce/themes/advanced/skins/highcontrast/e4.php?
• {BLOCKED}local.com/wp-content/plugins/e1.php
• {BLOCKED}meryfoodconsulting.com/wp-content/uploads/2015/03/update-b20ca6f3cf022a826b32ab34eb9cdbfb/tmp/e5.php
• {BLOCKED}efestas.net/wp-content/plugins/e1.php
• {BLOCKED}ojointreplacement.com/wp-content/plugins/e2.php
• {BLOCKED}ecleaners.net/wp-content/themes/Avada/framework/plugins/e5.php
• {BLOCKED}epers.org/wp-content/uploads/f/Avl/e4.php
• {BLOCKED}ngsolutions.net/wp-content/themes/secondtouch/options/options/fields/pages_select/e3.php
• {BLOCKED}eminars.com/wp-content/themes/headway/library/blocks/social/icons/peel-icons/e1.php
• {BLOCKED}eminars.com/wp-content/themes/headway/library/blocks/social/icons/peel-icons/e1.php?
• {BLOCKED}ai.com/wp-content1/themes/starter/lib/meta-box/js/jqueryui/timepicker-i18n/e1.php
• {BLOCKED}cility.com/pwksfmaw/klsjdvbss/e3.php
• {BLOCKED}mtravelhelp.net/userfiles/image/e4.php
• {BLOCKED}os.com/plugins/e3.php
• {BLOCKED}education.com/wp-content/plugins/e4.php
• {BLOCKED}education.com/wp-content/plugins/e4.php?
• {BLOCKED}ars.com/wp-content/themes/headway/library/blocks/social/icons/peel-icons/e1.php?

It deletes itself after execution.

NOTES:

This Trojan is capable of encrypting files.