TROJ_CRYPWALL.TXQ

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}{BLOCKED}e.biz.pl/wp-content/plugins/newsletter/tiny_mce/themes/advanced/skins/highcontrast/c.php
• http://{BLOCKED}{BLOCKED}olar.pl/wp-content/plugins/newsletter/tiny_mce/plugins/inlinepopups/skins/clearlooks2/img/b.php
• http://{BLOCKED}{BLOCKED}pa.ro/wp-content/themes/twentythirteen/a.php
• http://{BLOCKED}{BLOCKED}g-girl.org/wp-content/plugins/contact-form-7/includes/js/jquery-ui/themes/smoothness/images/e.php
• http://{BLOCKED}{BLOCKED}ental.com/wp-content/plugins/ml-slider/assets/sliders/nivoslider/themes/dark/e.php
• http://{BLOCKED}{BLOCKED}.pl/wp-content/plugins/newsletter/tiny_mce/themes/advanced/skins/o2k7/d.php
• http://{BLOCKED}{BLOCKED}ic.ro/wp-content/themes/twentytwelve/c.php
• http://{BLOCKED}{BLOCKED}c.pl/wp-content/plugins/newsletter/tiny_mce/themes/advanced/skins/default/img/b.php
• http://{BLOCKED}{BLOCKED}lserwa.com/wp-content/plugins/wp-db-backup-made/a.php
• http://{BLOCKED}{BLOCKED}bits.co.uk/blogbits/wp-content/themes/twentytwelve/e.php
• http://{BLOCKED}{BLOCKED}c.{BLOCKED}b.es/wordpress/wp-content/plugins/wp-db-backup-made1/d.php
• http://{BLOCKED}{BLOCKED}welry.com/il/wp-content/plugins/ninja-forms/includes/admin/pages/ninja-forms-settings/tabs/c.php
• http://{BLOCKED}{BLOCKED}ot.pl/wp-content/plugins/newsletter/tiny_mce/themes/advanced/skins/o2k7/img/b.php
• http://{BLOCKED}{BLOCKED}pl/wp-includes/js/tinymce/themes/advanced/skins/o2k7/img/a.php
• http://{BLOCKED}{BLOCKED}info.pl/wp-content/plugins/contact-form-7/includes/js/jquery-ui/themes/smoothness/e.php
• http://{BLOCKED}{BLOCKED}tech.pl/wp-content/themes/twentyeleven/d.php
• http://{BLOCKED}{BLOCKED}com/blog/wp-content/plugins/scribe/lib/history/views/meta-box/c.php
• http://{BLOCKED}{BLOCKED}a.pl/wp-content/plugins/newsletter/tiny_mce/themes/advanced/skins/default/b.php
• http://{BLOCKED}{BLOCKED}n.ru/wp-content/plugins/nextgen-gallery/products/photocrati_nextgen/modules/nextgen_gallery_display/templates/list/a.php
• http://{BLOCKED}{BLOCKED}com/wp-content/themes/twentythirteen/e.php
• http://{BLOCKED}{BLOCKED}m.pl/wordpress/wp-content/plugins/newsletter/emails/themes/pint/images/d.php
• http://{BLOCKED}{BLOCKED}entacademy.com/wp-content/plugins/wp-db-backup-made/c.php
• http://{BLOCKED}{BLOCKED}ty.pl/wp-content/plugins/newsletter/tiny_mce/themes/advanced/skins/o2k7/img/b.php
• http://{BLOCKED}{BLOCKED}nes.com/wp-content/themes/twentyeleven/a.php
• http://{BLOCKED}{BLOCKED}apartman.hu/de/wp-content/plugins/wp-db-backup-made/e.php
• http://{BLOCKED}{BLOCKED}ia.com/blog/wp-content/plugins/wp-db-backup-made/d.php
• http://{BLOCKED}{BLOCKED}g.com.pl/wp-content/plugins/newsletter/tiny_mce/themes/advanced/skins/o2k7/c.php
• http://{BLOCKED}{BLOCKED}deoyunlari.org/wp-content/themes/twentytwelve/b.php
• http://{BLOCKED}{BLOCKED}cz/wp-content/plugins/wp-db-backup-made/a.php
• http://{BLOCKED}{BLOCKED}o.com.br/site/wp-content/themes/twentyeleven/e.php
• http://{BLOCKED}{BLOCKED}p.pl/wp-content/plugins/newsletter/tiny_mce/themes/advanced/skins/highcontrast/d.php
• http://{BLOCKED}{BLOCKED}tariasaborearte.com.br/wp-content/plugins/wp-db-backup-made/c.php
• http://{BLOCKED}{BLOCKED}idadresponsable.com.mx/wp-content/plugins/_backupwordpress/vendor/mikey179/vfsStream/src/test/resources/b.php
• http://{BLOCKED}{BLOCKED}imagenes.com/wp-content/plugins/wp-mobile-edition/admin/includes/mobile_themes/mTheme-Unus/images/blue/a.php
• http://{BLOCKED}{BLOCKED}m.pl/wp-content/plugins/contact-form-7/includes/js/jquery-ui/themes/smoothness/images/e.php
• http://{BLOCKED}{BLOCKED}a.pl/wp-content/plugins/newsletter/tiny_mce/themes/advanced/skins/default/img/d.php
• http://{BLOCKED}{BLOCKED}a.pl/wp-content/plugins/newsletter/tiny_mce/themes/advanced/skins/o2k7/img/c.php
• http://{BLOCKED}{BLOCKED}a.pl/wp-content/plugins/newsletter/tiny_mce/themes/advanced/skins/o2k7/b.php
• http://{BLOCKED}{BLOCKED}ron.com/wp-content/plugins/contact-form-7/includes/js/jquery-ui/themes/smoothness/images/a.php

It deletes the initially executed copy of itself

NOTES:

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

It connects to the following non-malicious URLs:

• http://ip-addr.es
• http://myexternalip.com/raw
• http://curlmyip.com