Modified By:: Michael Jay Villanueva

 

Ransom:Win32/Mischa.A (Microsoft); Ransom.Mischa (Malwarebytes); Trojan-Ransom.Win32.Mikhail.a (Kaspersky)

 PLATFORM:

Windows

 OVER ALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE
Low
Medium
High
Critical

  • Threat Type:
    Trojan

  • Destructiveness:
    No

  • Encrypted:
     

  • 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: 24,576 bytes
File type: DLL
Memory resident: No
INITIAL SAMPLES RECEIVED DATE: 20 May 2016
PAYLOAD: Encrypts files, Displays message/message boxes

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 component file(s):

  • {encrypted file path}\YOUR_FILES_ARE_ENCRYPTED.TXT
  • {encrypted file path}\YOUR_FILES_ARE_ENCRYPTED.HTML

Other Details

This Trojan encrypts files with the following extensions:

  • .3dm
  • .3ds
  • .3fr
  • .3g2
  • .3ga
  • .3gp
  • .a2c
  • .aa
  • .aa3
  • .aac
  • .accdb
  • .aepx
  • .ai
  • .aif
  • .amr
  • .ape
  • .apnx
  • .ari
  • .arw
  • .asf
  • .asp
  • .aspx
  • .asx
  • .avi
  • .azw
  • .azw1
  • .azw3
  • .azw4
  • .bak
  • .bat
  • .bay
  • .bin
  • .bmp
  • .camproj
  • .cat
  • .ccd
  • .cdi
  • .cdr
  • .cer
  • .cert
  • .cfg
  • .cgi
  • .class
  • .cmf
  • .cnf
  • .conf
  • .config
  • .cpp
  • .cr2
  • .crt
  • .crw
  • .crwl
  • .cs
  • .csv
  • .cue
  • .dash
  • .dat
  • .db
  • .dbf
  • .dcr
  • .dcu
  • .dds
  • .default
  • .der
  • .dfm
  • .directory
  • .disc
  • .dll
  • .dmg
  • .dng
  • .doc
  • .docm
  • .docx
  • .dtd
  • .dvd
  • .dwg
  • .dxf
  • .eip
  • .emf
  • .eml
  • .eps
  • .epub
  • .erf
  • .exe
  • .fff
  • .flv
  • .frm
  • .gfx
  • .gif
  • .gzip
  • .h
  • .htm
  • .html
  • .ico
  • .idl
  • .iiq
  • .indd
  • .inf
  • .ini
  • .iso
  • .jar
  • .java
  • .jfif
  • .jge
  • .jpe
  • .jpeg
  • .jpg
  • .js
  • .json
  • .jsp
  • .k25
  • .kdc
  • .key
  • .ldf
  • .lib
  • .lit
  • .lnk
  • .localstorage
  • .log
  • .m3u
  • .m4a
  • .m4v
  • .max
  • .mdb
  • .mdf
  • .mef
  • .mkv
  • .mobi
  • .mov
  • .movie
  • .mp1
  • .mp2
  • .mp3
  • .mp4
  • .mp4v
  • .mpa
  • .mpe
  • .mpeg
  • .mpg
  • .mpv2
  • .mrw
  • .msg
  • .mts
  • .mui
  • .myi
  • .nef
  • .nrg
  • .nri
  • .nrw
  • .number
  • .obj
  • .odb
  • .odc
  • .odf
  • .odm
  • .odp
  • .ods
  • .odt
  • .ogg
  • .orf
  • .ost
  • .p12
  • .p7b
  • .p7c
  • .pages
  • .pas
  • .pbk
  • .pdd
  • .pdf
  • .pef
  • .pem
  • .pfx
  • .php
  • .png
  • .po
  • .pps
  • .ppt
  • .pptm
  • .pptx
  • .prf
  • .props
  • .ps
  • .psd
  • .pspimage
  • .pst
  • .ptx
  • .pub
  • .py
  • .qt
  • .r3d
  • .ra
  • .raf
  • .ram
  • .rar
  • .raw
  • .result
  • .rll
  • .rm
  • .rpf
  • .rtf
  • .rw2
  • .rwl
  • .sql
  • .sqlite
  • .sqllite
  • .sr2
  • .srf
  • .srt
  • .srw
  • .svg
  • .swf
  • .tga
  • .tiff
  • .toast
  • .ts
  • .txt
  • .vbs
  • .vcd
  • .vlc
  • .vmdk
  • .vmx
  • .vob
  • .wav
  • .wb2
  • .wdb
  • .wma
  • .wmv
  • .wpd
  • .wps
  • .x3f
  • .xlk
  • .xls
  • .xlsb
  • .xlsm
  • .xlsx
  • .xml
  • .xps
  • .xsl
  • .yml
  • .yuv
  • .zip

It renames encrypted files using the following names:

  • {original filename}.{4 random characters}

NOTES:

This ransomware avoids encrypting files located in the following folders:

  • \$Recycle.Bin
  • \Chrome
  • \Internet Explorer
  • \Local
  • \LocalLow
  • \Microsoft
  • \Mozilla Firefox
  • \Opera
  • \Temp
  • \Windows

It displays the following ransom notes:

  SOLUTION

Minimum scan engine: 9.800
First VSAPI Pattern File: 12.538.02
First VSAPI Pattern Release Date: 20 May 2016
VSAPI OPR PATTERN-VERSION: 12.539.00
VSAPI OPR PATTERN DATE: 21 May 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

Search and delete these files

[ learnMore ]
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.  
  • {encrypted file path}\YOUR_FILES_ARE_ENCRYPTED.TXT
  • {encrypted file path}\YOUR_FILES_ARE_ENCRYPTED.HTML

Step 4

Scan your computer with your Trend Micro product to delete files detected as RANSOM_MISCHA.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 this Knowledge Base page for more information.

Step 5

Restore encrypted files from backup.


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