TROJ_CRYPWALL.RI

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://blog.{BLOCKED}ages.com/wp-content/plugins/wp-antibot-standart2/r.php
• http://{BLOCKED}erage.com/wp-content/plugins/wp-antibot-standart/rrr.php
• http://{BLOCKED}d-yug.ru/wp-content/themes/estudio/rrrrr.php
• http://{BLOCKED}o.ru/wp-content/uploads/r.php
• http://{BLOCKED}gasiaabadi.com/modules/mod_tower/rr.php
• http://{BLOCKED}esexboys.com/wp-content/uploads/rrrr.php
• http://{BLOCKED}people.com.br/wp-content/themes/mazine/rrrrr.php
• http://{BLOCKED}venir.com/wp-content/uploads/r.php
• http://{BLOCKED}ibb.tv/wp-content/themes/Divi/rr.php
• http://{BLOCKED}egypt.com/blog/wp-content/themes/twentyfourteen/rrr.php
• http://{BLOCKED}eaguehomerepair.com/wp-content/uploads/rrrr.php
• http://{BLOCKED}eh.com/modules/mod_tower/rrrrr.php
• http://{BLOCKED}giyim.com/modules/mod_tower/r.php
• http://{BLOCKED}ahvesi.com/wp-content/uploads/rr.php
• http://{BLOCKED}k.cz/wp-content/uploads/rrrr.php
• http://{BLOCKED}d.pl/wp-content/uploads/rrrrr.php
• http://{BLOCKED}jewelry.com/wp-content/uploads/rr.php
• http://{BLOCKED}eep.com/wp-content/uploads/rrr.php
• http://{BLOCKED}cebakim.com/wp-content/uploads/rrrr.php
• http://{BLOCKED}west.net/wp-content/uploads/rrrrr.php
• http://{BLOCKED}azonia.com/wp-content/uploads/r.php
• http://{BLOCKED}u24.de/templates/atomic/rr.php
• http://{BLOCKED}b.kz/wp-content/uploads/rrr.php
• http://{BLOCKED}m.com/wp-content/themes/xinji/rrrr.php
• http://{BLOCKED}itects.com/wp-content/uploads/rrrrr.php
• http://{BLOCKED}management.ch/wp-content/uploads/r.php
• http://{BLOCKED}press.com/wp-content/uploads/rr.php
• http://{BLOCKED}yle1974.com/wp-content/uploads/rrr.php
• http://{BLOCKED}tage.com/wp-content/uploads/rrrr.php
• http://{BLOCKED}randucato.com/giro_2013/wp-content/uploads/rrrrr.php
• http://{BLOCKED}mias.com/wp-content/uploads/r.php
• http://{BLOCKED}i.net/wp-content/themes/twentytwelve/rr.php
• http://{BLOCKED}.com/wp-content/uploads/rrr.php
• http://{BLOCKED}la.com/wp-content/uploads/rrrr.php
• http://emyv.{BLOCKED}ista.org/wp-content/themes/channel/rrrrr.php
• http://{BLOCKED}titut-education.u-cergy.fr/wp-content/themes/twentyeleven/r.php
• http://{BLOCKED}ona.com/plugins/system/plg_system_rewrite/rr.php
• http://{BLOCKED}oleka.pl/wp-content/plugins/wp-antibot-standart/rrr.php
• http://{BLOCKED}ansas.com/wp-content/plugins/wp-antibot-standart/rrrr.php
• http://{BLOCKED}headbeauty.com/fhbt/wp-content/themes/twentyeleven/rrrrr.php
• http://demo1.{BLOCKED}glischemi.com/wp-content/themes/twentytwelve/r.php

It deletes the initially executed copy of itself

NOTES:

This Trojan 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