TROJ_CRYPWALL.CBQ158C

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}lane.co.id/site/ccccc.php
• http://{BLOCKED}ansas.com/wp-content/plugins/wp-antibot-standart/rrrr.php
• http://{BLOCKED}ona.com/plugins/system/plg_system_rewrite/rr.php
• http://{BLOCKED}ysts.com/wp-content/uploads/rrr.php
• http://{BLOCKED}ai.net/wp-content/themes/twentytwelve/rr.php
• http://{BLOCKED}mias.com/wp-content/uploads/r.php
• http://{BLOCKED}tage.com/wp-content/uploads/rrrr.php
• http://{BLOCKED}yle1974.com/wp-content/uploads/rrr.php
• http://{BLOCKED}m.com/wp-content/themes/xinji/rrrr.php
• http://{BLOCKED}ab.kz/wp-content/uploads/rrr.php
• http://{BLOCKED}24.de/templates/atomic/rr.php
• http://{BLOCKED}azonia.com/wp-content/uploads/r.php
• http://{BLOCKED}hcebakim.com/wp-content/uploads/rrrr.php
• http://{BLOCKED}eep.com/wp-content/uploads/rrr.php
• http://{BLOCKED}-jewelry.com/wp-content/uploads/rr.php
• http://{BLOCKED}d.pl/wp-content/uploads/rrrrr.php
• http://{BLOCKED}k.cz/wp-content/uploads/rrrr.php
• http://{BLOCKED}eaguehomerepair.com/wp-content/uploads/rrrr.php
• http://{BLOCKED}egypt.com/blog/wp-content/themes/twentyfourteen/rrr.php
• http://{BLOCKED}npeople.com.br/wp-content/themes/mazine/rrrrr.php
• http://{BLOCKED}nesexboys.com/wp-content/uploads/rrrr.php
• http://{BLOCKED}okerage.com/wp-content/plugins/wp-antibot-standart/rrr.php
• http://{BLOCKED}ross.com/wp-content/themes/twentyeleven/ccccc.php
• http://{BLOCKED}pan.com/wp-content/plugins/bwp-recent-comments/ccc.php
• http://{BLOCKED}ndermagic.com/wp-content/plugins/wp-quick-contact-us/cc.php
• http://{BLOCKED}midwifery.com/wp-content/plugins/ultimate-branding/c.php
• http://{BLOCKED}-x.com/wp-content/plugins/sitepress-multilingual-cms/ccccc.php
• http://{BLOCKED}zzauruguay.com/wp-content/wp-content/themes/twentythirteen/cccc.php
• http://{BLOCKED}zzabrasil.com/wp-content/plugins/revision-control/ccc.php
• http://{BLOCKED}zzacolombia.com/wp-content/plugins/pods/cc.php
• http://{BLOCKED}zzavenezuela.com/wp-content/plugins/stickyfooter/ccccc.php
• http://{BLOCKED}ityneuroclinic.com/wp-content/themes/twentytwelve/cccc.php
• http://{BLOCKED}zzachile.com/wp-content/plugins/gravityforms/ccc.php
• http://{BLOCKED}tao.com/wp-content/themes/twentyeleven/cc.php
• http://{BLOCKED}renderamaquillarse.com/wp-content/themes/twentyten/c.php
• http://{BLOCKED}scrosson.com/wp-content/plugins/woodojo/ccccc.php
• http://{BLOCKED}yfross.com/wp-content/themes/twentyfourteen/cccc.php
• http://{BLOCKED}sonakeychain.com/wp-content/plugins/wp-smushit/ccc.php
• http://{BLOCKED}t-into-cash.com/wp-content/plugins/pretty-link/cc.php
• http://{BLOCKED}h.com/wp-content/themes/twentytwelve/c.php
• http://{BLOCKED}comtechnologies.com/wp-content/plugins/jetpack/ccccc.php
• http://{BLOCKED}up.co.il/wp-content/plugins/revslider/temp/cccc.php
• http://{BLOCKED}-drivers.com/wp-content/plugins/revslider/temp/cc.php
• http://{BLOCKED}lnirs.com/wp-content/plugins/revslider/temp/c.php
• http://{BLOCKED}pranationalthailand.com/wp-content/cccc.php
• http://{BLOCKED}tofmycamera.com/albums/ccc.php
• http://{BLOCKED}toyou.com/download/cc.php
• http://{BLOCKED}aproci.mazury.pl/images/ccccc.php
• http://{BLOCKED}c.com/board/cccc.php
• http://{BLOCKED}h.com/ckfinder/cc.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 the folders where files are encrypted.

It connects to the following non-malicious URLs:

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