Analysis by: Byron Jon Gelera
 ALIASES:

Win32/Filecoder.AlmaLocker.B (ESET-NOD32)

 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

Canal de infecção: Dropped by other malware, 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.

It connects to certain websites to send and receive information.

  TECHNICAL DETAILS

Tipo de compactação: 403,968 bytes
Tipo de arquivo: EXE
Residente na memória: No
Data de recebimento das amostras iniciais: 10 Oct 2016
Carga útil: Connects to URLs/IPs, Displays graphics/image, 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 file(s)/component(s):

  • {Path of encrypted file}\!_HOW_TO_RESTORE_{random character}.txt
  • {Path of encrypted file}\!_HOW_TO_RESTORE_{random character}.htm
  • {Path of encrypted file}\!_HOW_TO_RESTORE_{random character}.url

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • ApiResolver

Other Details

This Trojan connects to the following URL(s) to get the affected system's IP address:

  • http://myexternalip.com/raw

It connects to the following website to send and receive information:

  • http://{BLOCKED}f6fqi63p6m.{BLOCKED}n.link/n.php

It encrypts files with the following extensions:

  • .1cd
  • .3ds
  • .3gp
  • .accdb
  • .ai
  • .ape
  • .asp
  • .aspx
  • .bc6
  • .bc7
  • .bmp
  • .cdr
  • .cer
  • .cfg
  • .cfgx
  • .cpp
  • .cr2
  • .crt
  • .crw
  • .csr
  • .csv
  • .dbf
  • .dbx
  • .dcr
  • .dfx
  • .dib
  • .djvu
  • .doc
  • .docm
  • .docx
  • .dwg
  • .dwt
  • .dxf
  • .dxg
  • .eps
  • .htm
  • .html
  • .ibank
  • .indd
  • .jfif
  • .jpe
  • .jpeg
  • .jpg
  • .kdc
  • .kwm
  • .max
  • .md
  • .mdb
  • .mdf
  • .odb
  • .odc
  • .odm
  • .odp
  • .ods
  • .odt
  • .orf
  • .p12
  • .p7b
  • .p7c
  • .pdf
  • .pef
  • .pem
  • .pfx
  • .php
  • .pl
  • .png
  • .pps
  • .ppt
  • .pptm
  • .pptx
  • .psd
  • .pst
  • .pub
  • .pwm
  • .py
  • .qbb
  • .qbw
  • .raw
  • .rtf
  • .sln
  • .sql
  • .sqlite
  • .svg
  • .tif
  • .tiff
  • .txt
  • .vcf
  • .wallet
  • .wpd
  • .xls
  • .xlsm
  • .xlsx
  • .xml

It renames encrypted files using the following names:

  • {orginal filename and extension}.{random character}

It does the following:

  • It skips to encrypt the following paths:
    • \$recycle.bin\
    • \system volume information\
    • \program files\
    • \programdata\
    • \program files (x86)\
    • \windows\
    • \internet explorer\
    • \microsoft\
    • \mozilla\
    • \chrome\
    • \appdata\
    • \local settings\
    • \recycler\
    • \msocache\
  • It displays the following ransom note:

  SOLUTION

Mecanismo de varredura mínima: 9.800
Primeiro arquivo padrão VSAPI: 12.828.06
Data do lançamento do primeiro padrão VSAPI: 10 Oct 2016
VSAPI OPR Pattern Version: 12.829.00
VSAPI OPR Pattern veröffentlicht am: 11 Oct 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

[ 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.  
  • {Path of encrypted file}\!_HOW_TO_RESTORE_{random character}.txt
  • {Path of encrypted file}\!_HOW_TO_RESTORE_{random character}.htm
  • {Path of encrypted file}\!_HOW_TO_RESTORE_{random character}.url

Step 4

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