RANSOM_CRYPWALL.XXUDO

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 connects to certain websites to send and receive information. 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:

• %Application Data%\{random 8 characters}\{random 10 characters}.exe

(Note: %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 drops and executes the following files:

• %Desktop%\HELP_YOUR_FILES.HTML
• %Desktop%\HELP_YOUR_FILES.PNG
• %Desktop%\HELP_YOUR_FILES.TXT

(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.)

It adds the following processes:

• explorer.exe
• svchost.exe

It is injected into the following processes running in memory:

• created explorer.exe
• created svchost.exe

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 8 characters} = "%Application Data%\{random 8 characters}\{random 10 characters}.exe"

Other System Modifications

This Trojan modifies the following registry entries:

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 website to send and receive information:

• {BLOCKED}e.info/nmWk4L.php
• {BLOCKED}usbalitour.com/oaUtAP.php
• {BLOCKED}arias.org/cSNFnR.php
• {BLOCKED}ranchconstruction.com/1X6sem.php
• {BLOCKED}ome.kz/GFyzb_.php
• {BLOCKED}ailsolutions.com/qO3tsI.php
• {BLOCKED}igeinkaufen.net/xcWeX2.php
• {BLOCKED}i.tv/s5XBx7.php
• {BLOCKED}lahilerdinle.com/1t_6Oz.php
• {BLOCKED}files.com/Jgl5qf.php
• {BLOCKED}lips.nl/c5kNwl.php
• {BLOCKED}ny.coolhandle-customer.com/nKcmBx.php
• {BLOCKED}e.com/otMD9Q.php
• {BLOCKED}tacey.com/TVOZ70.php
• {BLOCKED}pterpilotsalary.org/qz861j.php
• {BLOCKED}orever.com.au/fq0J3e.php
• {BLOCKED}rategies.com/fi6vTk.php
• {BLOCKED}aafkrimpen.nl/eDRVxU.php
• {BLOCKED}iatv.tv/RTSrQ1.php
• {BLOCKED}nger-spezialwerkzeuge.de/bqJk4H.php
• {BLOCKED}enpizza.net/iCl_jo.php
• {BLOCKED}enpizza.net/tnaDlE.php
• {BLOCKED}hoolingpena.com/L5fT7w.php
• {BLOCKED}.petanimal.org/sgiLtO.php
• {BLOCKED}vn/mBhkt1.php
• {BLOCKED}arestaurant.com/xtB4w2.php
• {BLOCKED}otproducts.com.au/bBDAV1.php
• {BLOCKED}org/5CK4p2.php
• {BLOCKED}teo.altervista.org/3JX12F.php
• {BLOCKED}onchurch.com/Af85yl.php
• {BLOCKED}elesyaalanlar.com.tr/xE8UZo.php
• {BLOCKED}erdinle.tv/9vmR0D.php
• {BLOCKED}erdinle.tv/HKoBDn.php
• {BLOCKED}dedcarsforsalesearch.com/DZsF1C.php
• {BLOCKED}pro/XNvu9U.php
• {BLOCKED}iousdiseases.mit.edu/3qUdQ9.php
• {BLOCKED}unistica.altervista.org/MIN69L.php
• {BLOCKED}unistica.altervista.org/ZVp8bY.php
• {BLOCKED}ot-heizstrahler.com/GbjRXH.php
• {BLOCKED}enetworks.in/vAqu3L.php
• {BLOCKED}sjekter.com/48aXyZ.php
• {BLOCKED}raman.com/tu3Qgx.php
• {BLOCKED}ul-escort-directory2.com/9uLF2l.php
• {BLOCKED}nguez.com/m_oBAr.php
• {BLOCKED}seng.sg/ISKFiW.php
• {BLOCKED}olitichour.com/8Qk_ab.php
• {BLOCKED}trauss.com/Letr2X.php
• {BLOCKED}trauss.com/r8Zb6m.php
• {BLOCKED}x.pl/Gml5B8.php
• {BLOCKED}a.dk/mDTyas.php
• {BLOCKED}n.in/UmLEDg.php
• {BLOCKED}ariatomasztomaszczyk.pl/QCiJW2.php
• {BLOCKED}mesajlari.org/g750fy.php
• {BLOCKED}ginspeed.its.ac.id/FeGAB4.php

It encrypts files with the following extensions:

• aif
• aifc
• aiff
• asf
• asx
• au
• bmp
• dib
• doc
• doc
• docx
• docx
• dot
• dot
• dvr-ms
• emf
• exe
• gif
• hta
• hta
• htm
• htm
• html
• html
• ico
• IVF
• jfif
• jpe
• jpeg
• jpg
• m1v
• m3u
• mht
• mid
• midi
• mp2
• mp2v
• mp3
• mpa
• mpe
• mpeg
• mpg
• mpv2
• pdf
• pdf
• png
• pot
• pot
• pps
• pps
• ppt
• ppt
• pptx
• pptx
• rle
• rmi
• rtf
• rtf
• search-ms
• snd
• tif
• tiff
• wav
• wax
• wm
• wma
• wmf
• wmv
• wmx
• wvx
• xbap
• xbap
• xls
• xls
• xlsx
• xlsx
• xlt
• xlt
• xlw
• xlw
• xml
• xml
• xps
• xps
• zip

It deletes the initially executed copy of itself

NOTES:

This malware searches all drives for files to encrypt except CD drive.

It deletes shadow copies by executing the following command:

vssadmin.exe Delete Shadows /All /Quiet

It avoids encrypting files with the following extensions:

• bas
• bat
• cmd
• com
• cpl
• lnk
• msi
• pif
• reg
• scr
• vb

It avoids encrypting files within the following folder names:

• application
• audio
• compressed
• document
• gamemedia
• image
• system
• text
• video

It renames encrypted files using the following names:

• {5 to 10 alphanumeric characters}.{2 to 5 alphanumeric characters}

Once the victim access the payment site specified in the ransom note, the browser displays the following Decrypt Service site: