Ransom.Win64.NERMER.A
Ransom:Win32/MedusaLocker.MK!MTB (Microsoft)
Windows
Threat Type: Ransomware
Destructiveness: No
Encrypted: No
In the wild: Yes
OVERVIEW
This Ransomware arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
It drops files as ransom note. It avoids encrypting files with the following file extensions.
TECHNICAL DETAILS
Arrival Details
This Ransomware 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 Ransomware adds the following processes:
- vssadmin.exe Resize ShadowStorage /for=c: /on=c: /maxsize=401MB
- vssadmin.exe Resize ShadowStorage /for=c: /on=c: /maxsize=unbounded
- vssadmin.exe Resize ShadowStorage /for=d: /on=d: /maxsize=401MB
- vssadmin.exe Resize ShadowStorage /for=d: /on=d: /maxsize=unbounded
- vssadmin.exe Resize ShadowStorage /for=e: /on=e: /maxsize=401MB
- vssadmin.exe Resize ShadowStorage /for=e: /on=e: /maxsize=unbounded
- vssadmin.exe Resize ShadowStorage /for=f: /on=f: /maxsize=401MB
- vssadmin.exe Resize ShadowStorage /for=f: /on=f: /maxsize=unbounded
- vssadmin.exe Resize ShadowStorage /for=g: /on=g: /maxsize=401MB
- vssadmin.exe Resize ShadowStorage /for=g: /on=g: /maxsize=unbounded
- vssadmin.exe Resize ShadowStorage /for=h: /on=h: /maxsize=401MB
- vssadmin.exe Resize ShadowStorage /for=h: /on=h: /maxsize=unbounded
- vssadmin.exe Delete Shadows /All /Quiet
- To delete backup:
- del /s /f /q c:\*.VHD c:\*.bac c:\*.bak c:\*.wbcat c:\*.bkf c:\Backup*.* c:\backup*.* c:\*.set c:\*.win c:\*.dsk
- del /s /f /q d:\*.VHD d:\*.bac d:\*.bak d:\*.wbcat d:\*.bkf d:\Backup*.* d:\backup*.* d:\*.set d:\*.win d:\*.dsk
- del /s /f /q e:\*.VHD e:\*.bac e:\*.bak e:\*.wbcat e:\*.bkf e:\Backup*.* e:\backup*.* e:\*.set e:\*.win e:\*.dsk
- del /s /f /q f:\*.VHD f:\*.bac f:\*.bak f:\*.wbcat f:\*.bkf f:\Backup*.* f:\backup*.* f:\*.set f:\*.win f:\*.dsk
- del /s /f /q g:\*.VHD g:\*.bac g:\*.bak g:\*.wbcat g:\*.bkf g:\Backup*.* g:\backup*.* g:\*.set g:\*.win g:\*.dsk
- del /s /f /q h:\*.VHD h:\*.bac h:\*.bak h:\*.wbcat h:\*.bkf h:\Backup*.* h:\backup*.* h:\*.set h:\*.win h:\*.dsk
- wbadmin DELETE SYSTEMSTATEBACKUP
- del %0
- bcdedit.exe /set {default} recoveryenabled No
- bcdedit.exe /set {default} bootstatuspolicy ignoreallfailures
- wmic.exe SHADOWCOPY /nointeractive
It adds the following mutexes to ensure that only one of its copies runs at any one time:
- {8761ABBD-7F85-42EE-B272-A76179687C63}
Autostart Technique
This Ransomware starts the following services:
- LanmanWorkstation
Other System Modifications
This Ransomware adds the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
System
EnableLinkedConnections = 1
Process Termination
This Ransomware terminates the following processes if found running in the affected system's memory:
- wxServer.exe
- wxServerView
- sqlservr.exe
- sqlmangr.exe
- RAgui.exe
- supervise.exe
- Culture.exe
- RTVscan.exe
- Defwatch.exe
- sqlbrowser.exe
- winword.exe
- Winword.exe
- onenotem.exe
- QBW32.exe
- QBDBMgr.exe
- qbupdate.xe
- QBCFMonitorService.exe
- axlbridge.exe
- QBIDPService.exe
- httpd.exe
- fdlauncher.exe
- MsDtsSrvr.exe
- sqlwriter.exe
- fdhost.exe
- ssms.exe
It terminates processes or services that contain any of the following strings if found running in the affected system's memory:
- wrapper
- DefWatch
- ccEvtMgr
- ccSetMgr
- SavRoam
- sqlservr
- sqlagent
- sqladhlp
- Culserver
- RTVscan
- sqlbrowser
- SQLADHLP
- QBIDPService
- Intuit.QuickBooks.FCS
- QBCFMonitorService
- sqlwriter
- msmdsrv
- MSSQLServerADHelper100
- MSSQLFDLauncher
- MSSQLSERVER
- MSSQLServerOLAPService
- SQLBrowser
- MsDtsServer100
- ReportServer
- SQLWriter
- SQLSERVERAGENT
Other Details
This Ransomware encrypts files with the following extensions:
- 123
- 1c
- 1cd
- 3dm
- 3ds
- 3fr
- 3g2
- 3gp
- 3pr
- 602
- 7z
- 7zip
- _ms
- aac
- ab4
- abd
- accdb
- accde
- accdr
- accdt
- ace
- ach
- acr
- act
- adb
- adi
- adp
- ads
- aes
- afi
- agdl
- ai
- aiff
- aii
- air
- ais
- ait
- aiv
- al
- alg
- allet
- ams
- aocla
- aoi
- apj
- apk
- arc
- arch00
- arm
- art
- arw
- arz
- asc
- asf
- asm
- asp
- aspx
- asset
- asx
- avhdx
- avi
- awg
- backup
- backupdb
- bank
- bar
- bat
- bay
- bc6
- bc7
- bck
- bco
- bdb
- bgt
- big
- bik
- bin
- bkf
- bkp
- bkup
- blend
- blob
- bmp
- bpn
- bpw
- brd
- bsa
- bsm
- bxl
- bz2
- cad
- cam
- cas
- cbk
- cbu
- cdf
- cdr
- cdr3
- cdr4
- cdr5
- cdr6
- cdrw
- cdx
- ce1
- ce2
- cel
- cer
- cert
- cf
- cfg
- cfr
- cgi
- cgm
- chg
- cib
- ckt
- class
- classpath
- cls
- cmd
- cmt
- cnf
- con
- config
- contact
- cpa
- cpi
- cpp
- cpr
- cr2
- craw
- crt
- crw
- cs
- csa
- csh
- cshtml
- csl
- csr
- css
- csv
- ctl
- cwz
- d3dbsp
- dac
- das
- data
- dazip
- db0
- db3
- db5
- db_journal
- dba
- dbc
- dbf
- dbs
- dbx
- dc2
- dch
- dcr
- dcs
- ddb
- ddd
- ddoc
- ddrw
- dds
- der
- des
- desc
- design
- dft
- dgc
- dif
- dip
- dit
- djvu
- dmp
- dng
- doc
- docb
- docm
- docx
- dot
- dotm
- dotx
- dra
- drf
- drl
- dru
- drw
- dsn
- dsnwrk
- dt
- dtd
- dwg
- dxb
- dxf
- dxg
- ecf
- edb
- edf
- elt
- eml
- emz
- epk
- eps
- erbsql
- erf
- esm
- ewprj
- exf
- fdb
- ff
- ffd
- fff
- fh
- fhd
- fla
- flac
- flf
- flp
- flv
- flvv
- fods
- fodt
- forge
- fos
- fp7
- fpd
- fpk
- fpx
- frm
- fsh
- fxg
- g1
- g2
- g3
- g4
- gbl
- gbo
- gbp
- gbr
- gbs
- gbx
- gdb
- gho
- gif
- gko
- gml
- gp
- gp1
- gp2
- gp3
- gp4
- gpb
- gpg
- gpt
- gray
- grb
- grey
- groups
- gry
- gtl
- gto
- gtp
- gts
- gwk
- gz
- hbk
- hdd
- hkdb
- hkx
- hplg
- hpp
- html
- hvpl
- hwp
- ibank
- ibd
- ibz
- icxs
- idb
- idc
- idx
- iif
- iiq
- incpas
- indd
- info
- ip
- ipc
- ism
- iso
- itdb
- itl
- itm
- iwd
- iwi
- ix
- jar
- java
- jnt
- jpe
- jpeg
- jpg
- jrl
- js
- jsp
- kc2
- kdb
- kdbx
- kdc
- kf
- kicad
- kpdx
- kwm
- laccdb
- lay
- lay6
- layout
- lbf
- lbr
- lc
- lck
- ldb
- ldf
- lg
- lgc
- lia
- lib
- libprj
- license
- licz
- lit
- litemod
- llx
- lmc
- log
- lrf
- ltx
- lua
- lvl
- lyt
- lzh
- lzma
- m2
- m2ts
- m3u
- m4a
- m4p
- m4u
- m4v
- map
- mapimail
- max
- mbx
- mcmeta
- md
- mdb
- mdbackup
- mdc
- mddata
- mdf
- mef
- menu
- mfw
- mid
- mkv
- mlb
- mlx
- mml
- mmw
- mny
- moneywell
- mos
- mov
- mp3
- mp4
- mpeg
- mpg
- mpqge
- mrg
- mrw
- mrwref
- msg
- mst
- mts
- myd
- myi
- mysql
- mysqli
- nbd
- nc
- ncf
- nd
- ndd
- ndf
- nef
- nk2
- nop
- nrw
- ns2
- ns3
- ns4
- nsd
- nsf
- nsg
- nsh
- ntl
- nvram
- nwb
- nx2
- nxl
- nyf
- oab
- obj
- obk
- odb
- odc
- odf
- odg
- odm
- odp
- ods
- odt
- oeb
- ogg
- oil
- olb
- one
- onetoc2
- opj
- opt
- ora
- orf
- ost
- otg
- oth
- otp
- ots
- ott
- p12
- p7b
- p7c
- pab
- pad
- pages
- pak
- paq
- par
- pas
- pat
- pbd
- pc
- pcb
- pcbdoc
- pcd
- pct
- pdb
- pdblib
- pdd
- pef
- pem
- pfx
- phj
- phl
- pho
- php
- pif
- pkpass
- pl
- plc
- plus_muhd
- png
- pot
- potm
- potx
- ppam
- ppc
- pps
- ppsm
- ppsx
- ppt
- pptm
- pptx
- prf
- prj
- prjcor
- prjemb
- prjpcb
- pro
- project
- prt
- ps
- ps1
- psafe3
- psc
- psd
- psk
- psm
- pspimage
- pst
- ptx
- pwm
- py
- q99
- qb1
- qba
- qbb
- qbk
- qbm
- qbmb
- qbmd
- qbquery
- qbr
- qbw
- qbx
- qby
- qcow
- qcow2
- qdf
- qed
- qfd
- qfx
- qic
- qif
- qmd
- qry
- quicken
- quicken2015backup
- quicken2016backup
- quicken2017backup
- qw5
- r3d
- raf
- rar
- rat
- raw
- rb
- rdb
- re4
- reu
- rgss3a
- rim
- rm
- rofl
- rou
- rtf
- rul
- rvt
- rw2
- rwl
- rwz
- s3db
- safe
- sal
- sas7bdat
- sav
- save
- say
- sb
- sbn
- sbx
- sch
- schdoc
- schlib
- sd0
- sda
- sdf
- sh
- shp
- shx
- sid
- sidd
- sidn
- sie
- sis
- sl2
- sl3
- sldm
- sldx
- slk
- slm
- sln
- snt
- snx
- spp
- sqb
- sql
- sqlite
- sqlite3
- sqlitedb
- sqr
- sr2
- srf
- srt
- srw
- ssq
- st4
- st5
- st6
- st7
- st8
- stc
- std
- sti
- stm
- stp
- stw
- stx
- sum
- suo
- svg
- swf
- sxc
- sxd
- sxg
- sxi
- sxm
- sxw
- syncdb
- t12
- t13
- tar
- tax
- tbk
- tcf
- tex
- tga
- tgz
- thm
- tib
- tif
- tiff
- tlg
- tmd
- tmp
- tor
- trn
- txt
- ub
- uop
- uot
- upk
- vb
- vbk
- vbm
- vbox
- vbs
- vcd
- vcf
- vdf
- vdi
- vfs0
- vhd
- vhdx
- vib
- vlb
- vmdk
- vmem
- vmsd
- vmx
- vmxf
- vob
- vom
- vpk
- vpp_pc
- vsd
- vsdx
- vtf
- w3x
- wab
- wad
- wallet
- wav
- wb2
- wbk
- wdb
- wk1
- wks
- wma
- wmo
- wmv
- wotreplay
- wpd
- wps
- x11
- x3f
- xf
- xg3
- xgo
- xis
- xla
- xlam
- xlc
- xlk
- xlm
- xlr
- xls
- xlsb
- xlsm
- xlsx
- xlt
- xltm
- xltx
- xlw
- xml
- xps
- xslt
- xxx
- ycbcra
- ydk
- zip
- zpd
- ztmp
It does the following:
- This ransomware can perform privilege escalation
- It encrypts in all existing drives of the affected system
- It encrypts files from network share
- It empties out the Recycle Bin
Ransomware Routine
This Ransomware avoids encrypting files found in the following folders:
- ALLUSERSPROFILE
- \AppData
- USERPROFILE
- ProgramData
- WINDIR
- ProgramW6432
- PROGRAMFILES(x86)
- SYSTEMDRIVE
- \Application Data
- \Intel
- \MSOCache
- \PerfLogs
- \Nvidia
- \NVIDIA Corporation
- \Users\All Users
It appends the following extension to the file name of the encrypted files:
- .nermer
It drops the following file(s) as ransom note:
- {Encrypted directory}\PROTECT_INFO.TXT
It avoids encrypting files with the following file extensions:
- exe
- dll
- sys
- ini
- lnk
- dat
- htmlx
- vxdh
SOLUTION
Step 1
Trend Micro Predictive Machine Learning detects and blocks malware at the first sign of its existence, before it executes on your system. When enabled, your Trend Micro product detects this malware under the following machine learning name:
- Troj.Win32.TRX.XXPE50FFF046
Step 2
Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 users must disable System Restore to allow full scanning of their computers.
Step 3
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 4
Identify and terminate files detected as Ransom.Win64.NERMER.A
- Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
- If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
- If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.
Step 5
Delete this registry value
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\Policies\System
- EnableLinkedConnections = 1
- EnableLinkedConnections = 1
Step 6
Search and delete these files
- {Encrypted directory}\PROTECT_INFO.TXT
Step 7
Scan your computer with your Trend Micro product to delete files detected as Ransom.Win64.NERMER.A. 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 the following Trend Micro Support pages for more information:
Step 8
Enabling Volume Shadow Service
- Run the command prompt (cmd.exe) as administrator.
- Enable Volume Shadow Service by typing the following command:
net start vss
Step 9
Enabling Windows Error Recovery
- Run the command prompt (cmd.exe) as administrator.
- Enable Windows Error Recovery Screen on Startup by typing the following command:
bcdedit /set {default} bootstatuspolicy displayallfailures
Step 10
Restore encrypted files from backup.
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