Analysis by: Francis Xavier Antazo
ALIASES:

Ransom:PowerShell/Poshkod.D (Microsoft), Win32/Filecoder.CS (ESET), Trojan-Ransom.Script.Agent.b (Kaspersky), Trojan.Cryptolocker (Symantec)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • 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.

  TECHNICAL DETAILS

File Size: 16,720 bytes
File Type: Script
Memory Resident: Yes
Initial Samples Received Date: 14 Jul 2015
Payload: Encrypts files

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.

Other Details

This Trojan encrypts files with the following extensions:

  • .doc
  • .xls
  • .docx
  • .xlsx
  • .mp3
  • .waw
  • .jpg
  • .jpeg
  • .txt
  • .rtf
  • .pdf
  • .rar
  • .zip
  • .psd
  • .tif
  • .wma
  • .gif
  • .bmp
  • .ppt
  • .pptx
  • .docm
  • .xlsm
  • .pps
  • .ppsx
  • .ppd
  • .eps
  • .png
  • .ace
  • .djvu
  • .tar
  • .cdr
  • .max
  • .wmv
  • .avi
  • .wav
  • .mp4
  • .pdd
  • .php
  • .aac
  • .ac3
  • .amf
  • .amr
  • .dwg
  • .dxf
  • .accdb
  • .mod
  • .tax2013
  • .tax2014
  • .oga
  • .ogg
  • .pbf
  • .ra
  • .raw
  • .saf
  • .val
  • .wave
  • .wow
  • .wpk
  • .3g2
  • .3gp
  • .3gp2
  • .3mm
  • .amx
  • .avs
  • .bik
  • .dir
  • .divx
  • .dvx
  • .evo
  • .flv
  • .qtq
  • .tch
  • .rts
  • .rum
  • .rv
  • .scn
  • .srt
  • .stx
  • .svi
  • .swf
  • .trp
  • .vdo
  • .wm
  • .wmd
  • .wmmp
  • .wmx
  • .wvx
  • .xvid
  • .3d
  • .3d4
  • .3df8
  • .pbs
  • .adi
  • .ais
  • .amu
  • .arr
  • .bmc
  • .bmf
  • .cag
  • .cam
  • .dng
  • .ink
  • .jif
  • .jiff
  • .jpc
  • .jpf
  • .jpw
  • .mag
  • .mic
  • .mip
  • .msp
  • .nav
  • .ncd
  • .odc
  • .odi
  • .opf
  • .qif
  • .qtiq
  • .srf
  • .xwd
  • .abw
  • .act
  • .adt
  • .aim
  • .ans
  • .asc
  • .ase
  • .bdp
  • .bdr
  • .bib
  • .boc
  • .crd
  • .diz
  • .dot
  • .dotm
  • .dotx
  • .dvi
  • .dxe
  • .mlx
  • .err
  • .euc
  • .faq
  • .fdr
  • .fds
  • .gthr
  • .idx
  • .kwd
  • .lp2
  • .ltr
  • .man
  • .mbox
  • .msg
  • .nfo
  • .now
  • .odm
  • .oft
  • .pwi
  • .rng
  • .rtx
  • .run
  • .ssa
  • .text
  • .unx
  • .wbk
  • .wsh
  • .7z
  • .arc
  • .ari
  • .arj
  • .car
  • .cbr
  • .cbz
  • .gz
  • .gzig
  • .jgz
  • .pak
  • .pcv
  • .puz
  • .r00
  • .r01
  • .r02
  • .r03
  • .rev
  • .sdn
  • .sen
  • .sfs
  • .sfx
  • .sh
  • .shar
  • .shr
  • .sqx
  • .tbz2
  • .tg
  • .tlz
  • .vsi
  • .wad
  • .war
  • .xpi
  • .z02
  • .z04
  • .zap
  • .zipx
  • .zoo
  • .ipa
  • .isu
  • .jar
  • .js
  • .udf
  • .adr
  • .ap
  • .aro
  • .asa
  • .ascx
  • .ashx
  • .asmx
  • .asp
  • .indd
  • .asr
  • .qbb
  • .bml
  • .cer
  • .cms
  • .crt
  • .dap
  • .htm
  • .moz
  • .svr
  • .url
  • .wdgt
  • .abk
  • .bic
  • .big
  • .blp
  • .bsp
  • .cgf
  • .chk
  • .col
  • .cty
  • .dem
  • .elf
  • .ff
  • .gam
  • .grf
  • .h3m
  • .h4r
  • .iwd
  • .ldb
  • .lgp
  • .lvl
  • .map
  • .md3
  • .mdl
  • .mm6
  • .mm7
  • .mm8
  • .nds
  • .pbp
  • .ppf
  • .pwf
  • .pxp
  • .sad
  • .sav
  • .scm
  • .scx
  • .sdt
  • .spr
  • .sud
  • .uax
  • .umx
  • .unr
  • .uop
  • .usa
  • .usx
  • .ut2
  • .ut3
  • .utc
  • .utx
  • .uvx
  • .uxx
  • .vmf
  • .vtf
  • .w3g
  • .w3x
  • .wtd
  • .wtf
  • .ccd
  • .cd
  • .cso
  • .disk
  • .dmg
  • .dvd
  • .fcd
  • .flp
  • .img
  • .iso
  • .isz
  • .md0
  • .md1
  • .md2
  • .mdf
  • .mds
  • .nrg
  • .nri
  • .vcd
  • .vhd
  • .snp
  • .bkf
  • .ade
  • .adpb
  • .dic
  • .cch
  • .ctt
  • .dal
  • .ddc
  • .ddcx
  • .dex
  • .dif
  • .dii
  • .itdb
  • .itl
  • .kmz
  • .lcd
  • .lcf
  • .mbx
  • .mdn
  • .odf
  • .odp
  • .ods
  • .pab
  • .pkb
  • .pkh
  • .pot
  • .potx
  • .pptm
  • .psa
  • .qdf
  • .qel
  • .rgn
  • .rrt
  • .rsw
  • .rte
  • .sdb
  • .sdc
  • .sds
  • .sql
  • .stt
  • .t01
  • .t03
  • .t05
  • .tcx
  • .thmx
  • .txd
  • .txf
  • .upoi
  • .vmt
  • .wks
  • .wmdb
  • .xl
  • .xlc
  • .xlr
  • .xlsb
  • .xltx
  • .ltm
  • .xlwx
  • .mcd
  • .cap
  • .cc
  • .cod
  • .cp
  • .cpp
  • .cs
  • .csi
  • .dcp
  • .dcu
  • .dev
  • .dob
  • .dox
  • .dpk
  • .dpl
  • .dpr
  • .dsk
  • .dsp
  • .eql
  • .ex
  • .f90
  • .fla
  • .for
  • .fpp
  • .jav
  • .java
  • .lbi
  • .owl
  • .pl
  • .plc
  • .pli
  • .pm
  • .res
  • .rsrc
  • .so
  • .swd
  • .tpu
  • .tpx
  • .tu
  • .tur
  • .vc
  • .yab
  • .8ba
  • .8bc
  • .8be
  • .8bf
  • .8bi8
  • .bi8
  • .8bl
  • .8bs
  • .8bx
  • .8by
  • .8li
  • .aip
  • .amxx
  • .ape
  • .api
  • .mxp
  • .oxt
  • .qpx
  • .qtr
  • .xla
  • .xlam
  • .xll
  • .xlv
  • .xpt
  • .cfg
  • .cwf
  • .dbb
  • .slt
  • .bp2
  • .bp3
  • .bpl
  • .clr
  • .dbx
  • .jc
  • .potm
  • .ppsm
  • .prc
  • .prt
  • .shw
  • .std
  • .ver
  • .wpl
  • .xlm
  • .yps
  • .md3
  • .1cd

NOTES:

It drops the following file once it successfully encrypts a file:

  • DECRYPT_INSTRUCTION.html

  SOLUTION

Minimum Scan Engine: 9.750
FIRST VSAPI PATTERN FILE: 11.808.04
FIRST VSAPI PATTERN DATE: 23 Jul 2015
VSAPI OPR PATTERN File: 11.809.00
VSAPI OPR PATTERN Date: 24 Jul 2015

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

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.  
  • DECRYPT_INSTRUCTION.html

Step 3

Scan your computer with your Trend Micro product to delete files detected as TROJ_POSHCODER.AB. 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.

NOTES:
Restore the encrypted files from backup.


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