Analysis by: Marvelous Pelin

 ALIASES:

Ransom:Win32/Cerber(Microsoft);Troj.Ransom.W32.Zerber!c(AegisLab)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet, Dropped by other malware

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 terminates itself if it detects it is being run in a virtual environment. It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size: 262,785 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 08 Feb 2017
Payload: Encrypts files, Displays message/message boxes, Connects to URLs/IPs

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:

  • %Desktop%\_HELP_HELP_HELP_{random}.jpg - ransom note
  • %Desktop%\_HELP_HELP_HELP_{random}.hta - ransom note
  • %User Temp%\{random name}.bmp - background image
  • {folders containing encrypted files}\_HELP_HELP_HELP_{random}.hta - ransom note
  • {folders containing encrypted files}\_HELP_HELP_HELP_{random}.jpg - ransom note

(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 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.)

Other System Modifications

This Trojan adds the following registry entries as part of its installation routine:

HKEY_CURRENT_USER\Control Panel\Desktop
Wallpaper = %User Temp%\{random filename}.bmp

Process Termination

This Trojan terminates the following processes if found running in the affected system's memory:

  • agntsvc.exeagntsvc.exe
  • agntsvc.exeencsvc.exe
  • agntsvc.exeisqlplussvc.exe
  • dbeng50.exe
  • dbsnmp.exe
  • firefoxconfig.exe
  • msftesql.exe
  • mydesktopqos.exe
  • mydesktopservice.exe
  • mysqld-nt.exe
  • mysqld-opt.exe
  • mysqld.exe
  • ocautoupds.exe
  • ocomm.exe
  • ocssd.exe
  • oracle.exe
  • sqbcoreservice.exe
  • sqlagent.exe
  • sqlbrowser.exe
  • sqlservr.exe
  • sqlwriter.exe
  • synctime.exe
  • tbirdconfig.exe
  • xfssvccon.exe
  • fbsever.exe

Other Details

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

  • Uses the following IP range via port 6892:
    • {BLOCKED}.{BLOCKED}xx2.1.0/27
    • {BLOCKED}.{BLOCKED}xx3.1.0/27
    • {BLOCKED}.{BLOCKED}239.24.0/23

It encrypts files with the following extensions:

  • .123
  • .1cd
  • .3dm
  • .3ds
  • .3fr
  • .3g2
  • .3gp
  • .3pr
  • .602
  • .7z
  • .7zip
  • .aac
  • .ab4
  • .abd
  • .acc
  • .accdb
  • .accde
  • .accdr
  • .accdt
  • .ach
  • .acr
  • .act
  • .adb
  • .adp
  • .ads
  • .aes
  • .agdl
  • .ai
  • .aiff
  • .ait
  • .al
  • .aoi
  • .apj
  • .apk
  • .arc
  • .arw
  • .ascx
  • .asf
  • .asm
  • .asp
  • .aspx
  • .asset
  • .asx
  • .atb
  • .avi
  • .awg
  • .back
  • .backup
  • .backupdb
  • .bak
  • .bank
  • .bat
  • .bay
  • .bdb
  • .bgt
  • .bik
  • .bin
  • .bkp
  • .blend
  • .bmp
  • .bpw
  • .brd
  • .bsa
  • .bz2
  • .c
  • .cash
  • .cdb
  • .cdf
  • .cdr
  • .cdr3
  • .cdr4
  • .cdr5
  • .cdr6
  • .cdrw
  • .cdx
  • .ce1
  • .ce2
  • .cer
  • .cfg
  • .cfn
  • .cgm
  • .cib
  • .class
  • .cls
  • .cmd
  • .cmt
  • .config
  • .contact
  • .cpi
  • .cpp
  • .cr2
  • .craw
  • .crt
  • .crw
  • .cry
  • .cs
  • .csh
  • .csl
  • .csr
  • .css
  • .csv
  • .d3dbsp
  • .dac
  • .das
  • .dat
  • .db
  • .db3
  • .db_journal
  • .dbf
  • .dbx
  • .dc2
  • .dch
  • .dcr
  • .dcs
  • .ddd
  • .ddoc
  • .ddrw
  • .dds
  • .def
  • .der
  • .des
  • .design
  • .dgc
  • .dgn
  • .dif
  • .dip
  • .dit
  • .djv
  • .djvu
  • .dng
  • .doc
  • .docb
  • .docm
  • .docx
  • .dot
  • .dotm
  • .dotx
  • .drf
  • .drw
  • .dtd
  • .dwg
  • .dxb
  • .dxf
  • .dxg
  • .edb
  • .eml
  • .eps
  • .erbsql
  • .erf
  • .exf
  • .fdb
  • .ffd
  • .fff
  • .fh
  • .fhd
  • .fla
  • .flac
  • .flb
  • .flf
  • .flv
  • .forge
  • .fpx
  • .frm
  • .fxg
  • .gbr
  • .gho
  • .gif
  • .gpg
  • .gray
  • .grey
  • .groups
  • .gry
  • .gz
  • .h
  • .hbk
  • .hdd
  • .hpp
  • .html
  • .hwp
  • .ibank
  • .ibd
  • .ibz
  • .idx
  • .iif
  • .iiq
  • .incpas
  • .indd
  • .info
  • .info_
  • .iwi
  • .jar
  • .java
  • .jnt
  • .jpe
  • .jpeg
  • .jpg
  • .js
  • .json
  • .k2p
  • .kc2
  • .kdbx
  • .kdc
  • .key
  • .kpdx
  • .kwm
  • .laccdb
  • .lay
  • .lay6
  • .lbf
  • .lck
  • .ldf
  • .lit
  • .litemod
  • .litesql
  • .lock
  • .ltx
  • .lua
  • .m
  • .m2ts
  • .m3u
  • .m4a
  • .m4p
  • .m4u
  • .m4v
  • .ma
  • .mab
  • .mapimail
  • .max
  • .mbx
  • .md
  • .mdb
  • .mdc
  • .mdf
  • .mef
  • .mfw
  • .mid
  • .mkv
  • .mlb
  • .mml
  • .mmw
  • .mny
  • .money
  • .moneywell
  • .mos
  • .mov
  • .mp3
  • .mp4
  • .mpeg
  • .mpg
  • .mrw
  • .ms11
  • .msf
  • .msg
  • .mts
  • .myd
  • .myi
  • .nd
  • .ndd
  • .ndf
  • .nef
  • .nk2
  • .nop
  • .nrw
  • .ns2
  • .ns3
  • .ns4
  • .nsd
  • .nsf
  • .nsg
  • .nsh
  • .nvram
  • .nwb
  • .nx2
  • .nxl
  • .nyf
  • .oab
  • .obj
  • .odb
  • .odc
  • .odf
  • .odg
  • .odm
  • .odp
  • .ods
  • .odt
  • .ogg
  • .oil
  • .omg
  • .one
  • .onenotec2
  • .orf
  • .ost
  • .otg
  • .oth
  • .otp
  • .ots
  • .ott
  • .p12
  • .p7b
  • .p7c
  • .pab
  • .pages
  • .paq
  • .pas
  • .pat
  • .pbf
  • .pcd
  • .pct
  • .pdb
  • .pdd
  • .pdf
  • .pef
  • .pem
  • .pfx
  • .php
  • .pif
  • .pl
  • .plc
  • .plus_muhd
  • .pm
  • .pm!
  • .pmi
  • .pmj
  • .pml
  • .pmm
  • .pmo
  • .pmr
  • .pnc
  • .pnd
  • .png
  • .pnx
  • .pot
  • .potm
  • .potx
  • .ppam
  • .pps
  • .ppsm
  • .ppsx
  • .ppt
  • .pptm
  • .pptx
  • .prf
  • .private
  • .ps
  • .psafe3
  • .psd
  • .pspimage
  • .pst
  • .ptx
  • .pub
  • .pwm
  • .py
  • .qba
  • .qbb
  • .qbm
  • .qbr
  • .qbw
  • .qbx
  • .qby
  • .qcow
  • .qcow2
  • .qed
  • .qtb
  • .r3d
  • .raf
  • .rar
  • .rat
  • .raw
  • .rb
  • .rdb
  • .re4
  • .rm
  • .rtf
  • .rvt
  • .rw2
  • .rwl
  • .rwz
  • .s3db
  • .safe
  • .sas7bdat
  • .sav
  • .save
  • .say
  • .sch
  • .sd0
  • .sda
  • .sdb
  • .sdf
  • .secret
  • .sh
  • .sldm
  • .sldx
  • .slk
  • .slm
  • .sql
  • .sqlite
  • .sqlite-shm
  • .sqlite-wal
  • .sqlite3
  • .sqlitedb
  • .sr2
  • .srb
  • .srf
  • .srs
  • .srt
  • .srw
  • .st4
  • .st5
  • .st6
  • .st7
  • .st8
  • .stc
  • .std
  • .sti
  • .stl
  • .stm
  • .stw
  • .stx
  • .svg
  • .swf
  • .sxc
  • .sxd
  • .sxg
  • .sxi
  • .sxm
  • .sxw
  • .tar
  • .tax
  • .tbb
  • .tbk
  • .tbn
  • .tex
  • .tga
  • .tgz
  • .thm
  • .tif
  • .tiff
  • .tlg
  • .tlx
  • .txt
  • .uop
  • .uot
  • .upk
  • .usr
  • .vb
  • .vbox
  • .vbs
  • .vdi
  • .vhd
  • .vhdx
  • .vmdk
  • .vmsd
  • .vmx
  • .vmxf
  • .vob
  • .vpd
  • .vsd
  • .wab
  • .wad
  • .wallet
  • .war
  • .wav
  • .wb2
  • .wk1
  • .wks
  • .wma
  • .wmf
  • .wmv
  • .wpd
  • .wps
  • .x11
  • .x3f
  • .xis
  • .xla
  • .xlam
  • .xlc
  • .xlk
  • .xlm
  • .xlr
  • .xls
  • .xlsb
  • .xlsm
  • .xlsx
  • .xlt
  • .xltm
  • .xltx
  • .xlw
  • .xml
  • .xps
  • .xxx
  • .ycbcra
  • .yuv
  • .zip

It renames encrypted files using the following names:

  • {10 Random Characters}.{4 Random}

It terminates itself if it detects it is being run in a virtual environment.

It does the following:

  • It checks for the path of installed AntiVirus, Firewall and AntiSpyware products then avoid encrypting files under those directories
  • It terminates itself if found running in any of the following countries:
    • Armenia
    • Azerbaijan
    • Belarus
    • Georgia
    • Kyrgyzstan
    • Kazakhstan
    • Moldova
    • Russia
    • Turkmenistan
    • Tajikistan
    • Ukraine
    • Uzbekistan
  • It avoids encrypting the following files:
    • bootsect.bak
    • iconcache.db
    • ntuser.dat
    • thumbs.db
  • It avoids encrypting files in the following paths:
    • :\\$getcurrent\\
    • :\\$recycle.bin\\
    • :\\$windows.~bt\\
    • :\\$windows.~ws\\
    • :\\boot\\
    • :\\documents and settings\\all users\\
    • :\\documents and settings\\default user\\
    • :\\documents and settings\\localservice\\
    • :\\documents and settings\\networkservice\\
    • :\\intel\\
    • :\\msocache\\
    • :\\perflogs\\
    • :\\program files (x86)\\
    • :\\program files\\
    • :\\programdata\\
    • :\\recovery\\
    • :\\recycled\\
    • :\\recycler\\
    • :\\systemvolume information\\
    • :\\temp\\
    • :\\windows.old\\
    • :\\windows10upgrade\\
    • :\\windows\\
    • :\\winnt\\
    • \\appdata\\local\\
    • \\appdata\\locallow\\
    • \\appdata\\roaming\\
    • \\local settings\\
    • \\public\\music\\sample music\\
    • \\public\\pictures\\samplepictures\\
    • \\public\\videos\\sample videos\\
    • \\tor browser\\
  • It speaks the following text using text-to-speech application:
    • "Attention! Attention! Attention! Your documents, photos, databases and other important files have been encrypted!"
  • It is configured to target related files under the following folders:
    • \\bitcoin\\
    • \\excel\\
    • \\microsoft sql server\\
    • \\microsoft\\excel\\
    • \\microsoft\\microsoftsql server\\
    • \\microsoft\\office\\
    • \\microsoft\\onenote\\
    • \\microsoft\\outlook\\
    • \\microsoft\\powerpoint\\
    • \\microsoft\\word\\
    • \\office\\
    • \onenote\
    • \outlook\
    • \powerpoint\
    • \steam\
    • \the bat!\
    • \thunderbird\
    • \word\

It deletes the initially executed copy of itself

NOTES:

The malware changes the affected system wallpaper to the following image:

The _HELP_HELP_HELP_{random}.hta contains the following information:

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 13.168.05
FIRST VSAPI PATTERN DATE: 20 Jan 2017
VSAPI OPR PATTERN File: 13.169.00
VSAPI OPR PATTERN Date: 21 Jan 2017

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

Search and delete these files

[ Learn More ]
There may be some files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
  • %Desktop%\_HELP_HELP_HELP_{random}.jpg
  • %Desktop%\_HELP_HELP_HELP_{random}.hta
  • %User Temp%\{random name}.bmp
  • {folders containing encrypted files}\_HELP_HELP_HELP_{random}.hta
  • {folders containing encrypted files}\_HELP_HELP_HELP_{random}.jpg

Step 5

Restart in normal mode and scan your computer with your Trend Micro product for files detected as RANSOM_CERBER.F117AK. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.

Step 6

Reset your Desktop properties

[ Learn More ]

Step 7

Restore encrypted files from backup.


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