RANSOM_ENIGMA.A

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 modifies the Internet Explorer Zone Settings.

It connects to certain websites to send and receive information.

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:

• %User Temp%\b815_appcompat.txt
• %Application Data%\testStart.txt
• %Desktop%\enigma_encr.txt -> Ransom Note (Text File)
• %Desktop%\allfilefinds.dat -> List of Searched/Encrypted Files
• %Desktop%\ENIGMA_682.RSA -> contains encryption key

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp 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.. %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.. %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 drops and executes the following files:

• %Desktop%\enigma.hta -> Ransom Note (Window Message)

(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.)

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
MyProgram = %Desktop%\{malware filename}.exe

Other System Modifications

This Trojan adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
MyProgramOk = %Desktop%\enigma.hta

Web Browser Home Page and Search Page Modification

This Trojan modifies the Internet Explorer Zone Settings.

Other Details

This Trojan connects to the following website to send and receive information:

• http://{BLOCKED}.{BLOCKED}.204.90/images/tuck.php

It encrypts files with the following extensions:

• .1cd
• .2d
• .3dc
• .7z
• .aes
• .asm
• .asp
• .asp
• .aspx
• .avi
• .bat
• .bmp
• .bz
• .bz2
• .bza
• .bzip
• .bzip2
• .cad
• .cd
• .cdr
• .cmd
• .cpp
• .crt
• .csr
• .csv
• .czip
• .dat
• .dbf
• .dif
• .djv
• .djvu
• .doc
• .docb
• .docm
• .docx
• .dwg
• .fla
• .gif
• .gz
• .gz
• .gz2
• .gza
• .gzi
• .gzip
• .hdoc
• .html
• .hwp
• .java
• .jpeg
• .jpg
• .key
• .kwm
• .lzma
• .max
• .mdb
• .mdb
• .mkv
• .mml
• .mov
• .mpeg
• .mpg
• .MYD
• .MYI
• .odg
• .odp
• .ods
• .odt
• .odt
• .otg
• .otp
• .ots
• .ott
• .pas
• .pem
• .php
• .php
• .png
• .pot
• .potm
• .potx
• .ppam
• .pps
• .ppsm
• .ppsx
• .ppt
• .ppt
• .pptm
• .pptx
• .pptx
• .psd
• .rar
• .rtf
• .rtf
• .slk
• .sln
• .sql
• .sqlite
• .sqlite
• .sqlite3
• .sqlitedb
• .sqx
• .sqz
• .srep
• .stc
• .std
• .sti
• .stw
• .swf
• .sxc
• .sxi
• .sxm
• .sxw
• .tar
• .taz
• .tbk
• .tbz
• .tbz2
• .tg
• .tgz
• .tif
• .tiff
• .tlz
• .tlzma
• .tsk
• .tx_
• .txt
• .txz
• .tz
• .uc2
• .uot
• .vbs
• .vdi
• .wks
• .wmv
• .xlc
• .xlm
• .xls
• .xlsb
• .xlsm
• .xlsx
• .xlsx
• .xlt
• .xltm
• .xltx
• .xlw
• .xz
• .zi
• .zip
• .zip
• .zipx
• .zix

It renames encrypted files using the following names:

• {Original Filename}.enigma
  • ie. Sample.txt.enigma

It does the following:

• It deletes shadow copies by executing the following command:
  • vssadmin delete shadows /all /quiet

NOTES:

It deletes files found in all drives with the following extensions:

• .aba
• .abf
• .abk
• .acp
• .as4
• .asd
• .ashbak
• .asvx
• .ate
• .ati
• .bac
• .bak
• .bak
• .bak~
• .bak2
• .bak3
• .bakx
• .bbb
• .bbz
• .bck
• .bckp
• .bcm
• .bk1
• .bk1
• .bkc
• .bkf
• .bkp
• .bks
• .blend1
• .blend2
• .bm3
• .bpa
• .bpb
• .bpm
• .bpn
• .bps
• .bup
• .bup
• .cbk
• .cbu
• .ck9
• .crds
• .da0
• .dash
• .dba
• .dbk
• .diy
• .dna
• .dov
• .fbc
• .fbf
• .fbk
• .fbk
• .fbu
• .fbw
• .fh
• .fhf
• .flka
• .flkb
• .fpsx
• .ftmb
• .ful
• .fza
• .gb1
• .gb2
• .gbp
• .gho
• .ghs
• .icf
• .ipd
• .iv2i
• .jbk
• .jdc
• .kb2
• .lcb
• .llx
• .mbk
• .mbw
• .mddata
• .mdinfo
• .mem
• .mig
• .mpb
• .mv_
• .nb7
• .nba
• .nbak
• .nbd
• .nbd
• .nbf
• .nbf
• .nbi
• .nbk
• .nbs
• .nbu
• .nco
• .nfb
• .nfc
• .npf
• .nps
• .nrbak
• .nrs
• .nwbak
• .obk
• .oeb
• .old
• .onepkg
• .ori
• .orig
• .paq
• .pbb
• .pbj
• .qba
• .qbb
• .qbk
• .qbm
• .qbmb
• .qbmd
• .qbx
• .qic
• .qsf
• .rbc
• .rbf
• .rbk
• .rbs
• .rdb
• .rgmb
• .rmbak
• .rrr
• .sbb
• .sbs
• .sbu
• .skb
• .sn1
• .sn2
• .sna
• .sns
• .spf
• .spg
• .spi
• .srr
• .stg
• .sv$
• .sv2i
• .tbk
• .tdb
• .tig
• .tis
• .tlg
• .tlg
• .tmr
• .trn
• .ttbk
• .uci
• .v2i
• .vbk
• .vbm
• .vpcbackup
• .vrb
• .wbb
• .wbcat
• .win
• .win
• .wjf
• .wpb
• .wspak
• .xlk
• .yrcbck