RANSOM_COVERT


 ALIASES:

Win32/Filecoder.Coverton.A (ESET), Trojan.Ransomcrypt.AF (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


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:

Varies

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

11 Apr 2016

Payload:

Connects to URLs/IPs, 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.

Installation

This Trojan drops the following files:

  • %Desktop%\!!!-WARNING-!!!.html - ransom note
  • %Desktop%\!!!-WARNING-!!!.txt - ransom note
  • {folders containing encrypted files}\!!!-WARNING-!!!.html - ransom note
  • {folders containing encrypted files}\!!!-WARNING-!!!.txt - 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.)

It drops the following copies of itself into the affected system:

  • %System%\crrss.exe
  • %User Profile%\userlog.exe

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)

Autostart Technique

This Trojan adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
crrss = "%System%\crrss.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
userlog = "%User Profile%\userlog.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Userinit = "C:\WINDOWS\system32\userinit.exe,C:\WINDOWS\system32\crrss.exe"

Other Details

This Trojan encrypts files with the following extensions:

  • 1cd
  • dbf
  • dt
  • cf
  • cfu
  • mxl
  • epf
  • kdbx
  • erf
  • vrp
  • grs
  • geo
  • st
  • pff
  • mft
  • efd
  • 3dm
  • 3ds
  • rib
  • ma
  • sldasm
  • sldprt
  • max
  • blend
  • lwo
  • lws
  • m3d
  • mb
  • obj
  • x
  • x3d
  • c4d
  • fbx
  • dgn
  • dwg
  • 4db
  • 4dl
  • 4mp
  • abs
  • accdb
  • accdc
  • accde
  • accdr
  • accdt
  • accdw
  • accft
  • adn
  • a3d
  • adp
  • aft
  • ahd
  • alf
  • ask
  • awdb
  • azz
  • bdb
  • bib
  • bnd
  • bok
  • btr
  • bak
  • backup
  • cdb
  • ckp
  • clkw
  • cma
  • crd
  • daconnections
  • dacpac
  • dad
  • dadiagrams
  • daf
  • daschema
  • db
  • db2
  • db3
  • dbc
  • dbk
  • dbs
  • dbt
  • dbv
  • dbx
  • dcb
  • dct
  • dcx
  • ddl
  • df1
  • dmo
  • dnc
  • dp1
  • dqy
  • dsk
  • dsn
  • dta
  • dtsx
  • dxl
  • eco
  • ecx
  • edb
  • emd
  • eql
  • fcd
  • fdb
  • fic
  • fid
  • fil
  • fm5
  • fmp
  • fmp12
  • fmpsl
  • fol
  • fp3
  • fp4
  • fp5
  • fp7
  • fpt
  • fzb
  • fzv
  • gdb
  • gwi
  • hdb
  • his
  • ib
  • idc
  • ihx
  • itdb
  • itw
  • jtx
  • kdb
  • lgc
  • maq
  • mdb
  • mdbhtml
  • mdf
  • mdn
  • mdt
  • mrg
  • mud
  • mwb
  • s3m
  • myd
  • ndf
  • ns2
  • ns3
  • ns4
  • nsf
  • nv2
  • nyf
  • oce
  • odb
  • oqy
  • ora
  • orx
  • owc
  • owg
  • oyx
  • p96
  • p97
  • pan
  • pdb
  • pdm
  • phm
  • pnz
  • pth
  • pwa
  • qpx
  • qry
  • qvd
  • rctd
  • rdb
  • rpd
  • rsd
  • sbf
  • sdb
  • sdf
  • spq
  • sqb
  • stp
  • sql
  • sqlite
  • sqlite3
  • sqlitedb
  • str
  • tcx
  • tdt
  • te
  • teacher
  • tmd
  • trm
  • udb
  • usr
  • v12
  • vdb
  • vpd
  • wdb
  • wmdb
  • xdb
  • xld
  • xlgc
  • zdb
  • zdc
  • cdr
  • cdr3
  • ppt
  • pptx
  • 1st
  • abw
  • act
  • aim
  • ans
  • apt
  • asc
  • ascii
  • ase
  • aty
  • awp
  • awt
  • aww
  • bad
  • bbs
  • bdp
  • bdr
  • bean
  • bna
  • boc
  • btd
  • bzabw
  • chart
  • chord
  • cnm
  • crwl
  • cyi
  • dca
  • dgs
  • diz
  • dne
  • doc
  • docm
  • docx
  • docxml
  • docz
  • dot
  • dotm
  • dotx
  • dsv
  • dvi
  • dx
  • eio
  • eit
  • email
  • emlx
  • epp
  • err
  • etf
  • etx
  • euc
  • fadein
  • faq
  • fb2
  • fbl
  • fcf
  • fdf
  • fdr
  • fds
  • fdt
  • fdx
  • fdxt
  • fes
  • fft
  • flr
  • fodt
  • fountain
  • gtp
  • frt
  • fwdn
  • fxc
  • gdoc
  • gio
  • gpn
  • gsd
  • gthr
  • gv
  • hbk
  • hht
  • hs
  • htc
  • hwp
  • hz
  • idx
  • iil
  • ipf
  • jarvis
  • jis
  • joe
  • jp1
  • jrtf
  • kes
  • klg
  • knt
  • kon
  • kwd
  • latex
  • lbt
  • lis
  • lit
  • lnt
  • lp2
  • lrc
  • lst
  • ltr
  • ltx
  • lue
  • luf
  • lwp
  • lxfml
  • lyt
  • lyx
  • man
  • map
  • mbox
  • md5txt
  • me
  • mell
  • min
  • mnt
  • msg
  • mwp
  • nfo
  • njx
  • notes
  • now
  • nwctxt
  • nzb
  • ocr
  • odm
  • odo
  • odt
  • ofl
  • oft
  • openbsd
  • ort
  • ott
  • p7s
  • pages
  • pfs
  • pfx
  • pjt
  • plantuml
  • prt
  • psw
  • pu
  • pvj
  • pvm
  • pwi
  • pwr
  • qdl
  • readme
  • rft
  • ris
  • rng
  • rpt
  • rst
  • rt
  • rtd
  • rtf
  • rtx
  • run
  • rzk
  • rzn
  • saf
  • safetext
  • sam
  • scc
  • scm
  • scriv
  • scrivx
  • sct
  • scw
  • sdm
  • sdoc
  • sdw
  • sgm
  • sig
  • skcard
  • sla
  • slagz
  • sls
  • smf
  • sms
  • ssa
  • strings
  • stw
  • sty
  • sub
  • sxg
  • sxw
  • tab
  • tdf
  • tex
  • text
  • thp
  • tlb
  • tm
  • tmv
  • tmx
  • tpc
  • trelby
  • tvj
  • txt
  • u3d
  • u3i
  • unauth
  • unx
  • uof
  • uot
  • upd
  • utf8
  • unity
  • utxt
  • vct
  • vnt
  • vw
  • wbk
  • wcf
  • webdoc
  • wgz
  • wn
  • wp
  • wp4
  • wp5
  • wp6
  • wp7
  • wpa
  • wpd
  • wpl
  • wps
  • wpt
  • wpw
  • wri
  • wsc
  • wsd
  • wsh
  • wtx
  • xbdoc
  • xbplate
  • xdl
  • xlf
  • xps
  • xwp
  • xy3
  • xyp
  • xyw
  • ybk
  • yml
  • zabw
  • zw
  • 2bp
  • 3fr
  • 73i
  • 8xi
  • 9png
  • abm
  • afx
  • agif
  • agp
  • aic
  • albm
  • apd
  • apm
  • apng
  • aps
  • apx
  • art
  • artwork
  • arw
  • asw
  • avatar
  • bay
  • blkrt
  • bm2
  • bmp
  • bmx
  • bmz
  • brk
  • brn
  • brt
  • bss
  • bti
  • c4
  • cal
  • cals
  • can
  • cd5
  • cdc
  • cdg
  • cimg
  • cin
  • cit
  • colz
  • cpc
  • cpd
  • cpg
  • cps
  • cpx
  • cr2
  • ct
  • dc2
  • dcr
  • dds
  • dgt
  • dib
  • dicom
  • djv
  • djvu
  • dm3
  • dmi
  • vue
  • dpx
  • wire
  • drz
  • dt2
  • dtw
  • dvl
  • ecw
  • eip
  • exr
  • fal
  • fax
  • fpos
  • fpx
  • g3
  • gcdp
  • gfb
  • gfie
  • ggr
  • gif
  • gih
  • gim
  • gmbck
  • gmspr
  • spr
  • scad
  • gpd
  • gro
  • grob
  • hdp
  • hdr
  • hpi
  • i3d
  • icn
  • icon
  • icpr
  • iiq
  • info
  • int
  • ipx
  • itc2
  • iwi
  • j
  • j2c
  • j2k
  • jas
  • jb2
  • jbig
  • jbig2
  • jbmp
  • jbr
  • jfif
  • jia
  • jng
  • jp2
  • jpe
  • jpeg
  • jpg
  • jpg2
  • jps
  • jpx
  • jtf
  • jwl
  • jxr
  • kdc
  • kdi
  • kdk
  • kic
  • kpg
  • lbm
  • ljp
  • mac
  • mbm
  • mef
  • mnr
  • mos
  • mpf
  • mpo
  • mrxs
  • myl
  • ncr
  • nct
  • nlm
  • nrw
  • oc3
  • oc4
  • oc5
  • oci
  • omf
  • oplc
  • af2
  • af3
  • ai
  • asy
  • cdmm
  • cdmt
  • cdmtz
  • cdmz
  • cdt
  • cgm
  • cmx
  • cnv
  • csy
  • cv5
  • cvg
  • cvi
  • cvs
  • cvx
  • cwt
  • cxf
  • dcs
  • ded
  • design
  • dhs
  • dpp
  • drw
  • dxb
  • dxf
  • egc
  • emf
  • ep
  • eps
  • epsf
  • fh10
  • fh11
  • fh3
  • fh4
  • fh5
  • fh6
  • fh7
  • fh8
  • fif
  • fig
  • fmv
  • ft10
  • ft11
  • ft7
  • ft8
  • ft9
  • ftn
  • fxg
  • gdraw
  • gem
  • glox
  • hpg
  • hpgl
  • hpl
  • idea
  • igt
  • igx
  • imd
  • ink
  • lmk
  • mgcb
  • mgmf
  • mgmt
  • mt9
  • mgmx
  • mgtx
  • mmat
  • mat
  • otg
  • ovp
  • ovr
  • pcs
  • pfd
  • pfv
  • pl
  • plt
  • pm
  • vrml
  • pmg
  • pobj
  • ps
  • psid
  • rdl
  • scv
  • sk1
  • sk2
  • slddrt
  • snagitstamps
  • snagstyles
  • ssk
  • stn
  • svf
  • svg
  • svgz
  • sxd
  • tlc
  • tne
  • ufr
  • vbr
  • vec
  • vml
  • vsd
  • vsdm
  • vsdx
  • vstm
  • stm
  • vstx
  • wmf
  • wpg
  • vsm
  • vault
  • xar
  • xmind
  • xmmap
  • yal
  • orf
  • ota
  • oti
  • ozb
  • ozj
  • ozt
  • pal
  • pano
  • pap
  • pbm
  • pc1
  • pc2
  • pc3
  • pcd
  • pcx
  • pdd
  • pdn
  • pe4
  • pef
  • pfi
  • pgf
  • pgm
  • pi1
  • pi2
  • pi3
  • pic
  • pict
  • pix
  • pjpeg
  • pjpg
  • png
  • pni
  • pnm
  • pntg
  • pop
  • pp4
  • pp5
  • ppm
  • prw
  • psd
  • psdx
  • pse
  • psp
  • pspbrush
  • ptg
  • ptx
  • pvr
  • px
  • pxr
  • pz3
  • pza
  • pzp
  • pzs
  • z3d
  • qmg
  • ras
  • rcu
  • rgb
  • rgf
  • ric
  • riff
  • rix
  • rle
  • rli
  • rpf
  • rri
  • rs
  • rsb
  • rsr
  • rw2
  • rwl
  • s2mv
  • sai
  • sci
  • sep
  • sfc
  • sfera
  • sfw
  • skm
  • sld
  • sob
  • spa
  • spe
  • sph
  • spj
  • spp
  • sr2
  • srw
  • ste
  • sumo
  • sva
  • save
  • ssfn
  • t2b
  • tb0
  • tbn
  • tfc
  • tg4
  • thm
  • thumb
  • tif
  • tiff
  • tjp
  • tm2
  • tn
  • tpi
  • ufo
  • uga
  • vda
  • vff
  • vpe
  • vst
  • wb1
  • wbc
  • wbd
  • wbm
  • wbmp
  • wbz
  • wdp
  • webp
  • wpb
  • wpe
  • wvl
  • x3f
  • y
  • ysp
  • zif
  • cdr4
  • cdr6
  • cdrw
  • pdf
  • ddoc
  • css
  • pptm
  • raw
  • cpt
  • tga
  • xpm
  • ani
  • flc
  • fb3
  • fli
  • mng
  • smil
  • mobi
  • swf
  • html
  • xls
  • xlsx
  • csv
  • xlsm
  • ods
  • xhtml
  • maf
  • asp
  • aspx
  • php
  • mhtml
  • wlmp
  • 7z
  • 7z001
  • 7z002
  • a00
  • a01
  • a02
  • ace
  • agg
  • ain
  • alz
  • apz
  • ar
  • arc
  • arh
  • ari
  • arj
  • ark
  • axx
  • b1
  • b64
  • ba
  • bh
  • bhx
  • bndl
  • boo
  • bz
  • bz2
  • bza
  • bzip
  • bzip2
  • c00
  • c01
  • c02
  • c10
  • car
  • cb7
  • cba
  • cbr
  • cbz
  • cdz
  • cp9
  • czip
  • dd
  • deb
  • dgc
  • dist
  • dz
  • ecs
  • efw
  • epi
  • f
  • fdp
  • fp8
  • gca
  • gmz
  • gz
  • gz2
  • gza
  • gzi
  • gzip
  • ha
  • hbc
  • hbc2
  • hbe
  • hki
  • hki1
  • hki2

It does the following:

  • It executes the following process to delete shadow copies:
    • vssadmin.exe delete shadows /all /quiet
  • It appends the extension .coverton to the encrypted files
  • It connects to the following C&C server to report infection status:
    • http://{BLOCKED}othetoma.bit/idea.php

    POST: task=report&id=%s&start_time=%d&start_crypt_time=%d&end_crypt_time=%d&count_files_crypted=%d&count_files_nomask=%d&count_dir_stop_word=%d&count_files_already_crypted=%d&count_files_write_error=%d&crypt_size_kb=%I64d&skip_block=%d

  • The following information are sent to the server:
    • unique victim ID
    • Time of encryption started
    • Time of encryption ended
    • Number of encrypted files
    • Number of files unsuccessfully encrypted
    • Total size of encrypted files

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

12.460.05

FIRST VSAPI PATTERN DATE:

11 Apr 2016

VSAPI OPR PATTERN File:

12.461.00

VSAPI OPR PATTERN Date:

12 Apr 2016

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 this file

[ 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.
  • !!!-WARNING-!!!.html
  • !!!-WARNING-!!!.txt

Step 5

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

 
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • crrss = "%System%\crrss.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • userlog = "%User Profile%\userlog.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • Userinit = "C:\WINDOWS\system32\userinit.exe,C:\WINDOWS\system32\crrss.exe"

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as RANSOM_COVERT. 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 7

Restore encrypted files from backup.


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