Analysis by: Francis Xavier Antazo

ALIASES:

a variant of MSIL/Filecoder.AK (ESET); Ransom.HiddenTear (AVG); Trojan.Filecoder (Malwarebytes);

 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.

It connects to certain websites to send and receive information. It gathers information and reports it to its servers.

  TECHNICAL DETAILS

File Size: 98816 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 07 Nov 2016
Payload: Renames Files, Encrypts Files, Terminates processes, Drops files, Connects to URLs/IPs, Steals information

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 copies of itself into the affected system and executes them:

  • %Application Data\{original file name and file extension}

It drops the following files:

  • %Desktop%\HOW_TO_RESTORE_YOUR_DATA.html {ransom note}
  • %Application Data%\HOW_TO_RESTORE_YOUR_DATA.html {ransom note}
  • {folders where it is able to encrypt files}\HOW_TO_RESTORE_YOUR_DATA.html {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.. %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming on 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.)

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Traxxio = "%Application Data\{original file name and file extension}"

Other System Modifications

This Trojan adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main\FeatureControl\
FEATURE_LOCALMACHINE_LOCKDOWN
iexplore.exe = "0"

Process Termination

This Trojan terminates the following processes if found running in the affected system's memory:

  • CryptoMonitor

Other Details

This Trojan connects to the following website to send and receive information:

  • http://{BLOCKED}t.pw/ransom/landing/gate.php?hwid=

It encrypts files with the following extensions:

  • .jpg
  • .JPEG
  • .JPG
  • .jpeg
  • .raw
  • .tif
  • .gif
  • .png
  • .bmp
  • .3dm
  • .max
  • .accdb
  • .db
  • .dbf
  • .mdb
  • .pdb
  • .sql
  • .sav
  • .spv
  • .grle
  • .mlx
  • .sv5
  • .game
  • .slot
  • .dwg
  • .dxf
  • .c
  • .cpp
  • .cs
  • .h
  • .php
  • .asp
  • .rb
  • .java
  • .jar
  • .class
  • .aaf
  • .aep
  • .aepx
  • .plb
  • .prel
  • .prproj
  • .aet
  • .ppj
  • .psd
  • .indd
  • .indl
  • .indt
  • .indb
  • .inx
  • .idml
  • .pmd
  • .xqx
  • .xqx
  • .ai
  • .eps
  • .ps
  • .svg
  • .swf
  • .fla
  • .as3
  • .as
  • .txt
  • .doc
  • .dot
  • .docx
  • .docm
  • .dotx
  • .dotm
  • .docb
  • .rtf
  • .wpd
  • .wps
  • .msg
  • .pdf
  • .xls
  • .xlt
  • .xlm
  • .xlsx
  • .xlsm
  • .xltx
  • .xltm
  • .xlsb
  • .xla
  • .xlam
  • .xll
  • .xlw
  • .ppt
  • .pot
  • .pps
  • .pptx
  • .pptm
  • .potx
  • .potm
  • .ppam
  • .ppsx
  • .ppsm
  • .sldx
  • .sldm
  • .wav
  • .mp3
  • .aif
  • .iff
  • .m3u
  • .m4u
  • .mid
  • .mpa
  • .wma
  • .ra
  • .avi
  • .mov
  • .mp4
  • .3gp
  • .mpeg
  • .3g2
  • .asf
  • .asx
  • .flv
  • .mpg
  • .wmv
  • .vob
  • .m3u8
  • .csv
  • .efx
  • .sdf
  • .vcf
  • .xml
  • .ses
  • .dat
  • .RAW
  • .TIF
  • .GIF
  • .PNG
  • .BMP
  • .3DM
  • .MAX
  • .ACCDB
  • .DB
  • .DBF
  • .MDB
  • .PDB
  • .SQL
  • .SAV
  • .SPV
  • .GRLE
  • .MLX
  • .SV5
  • .GAME
  • .SLOT
  • .DWG
  • .DXF
  • .C
  • .CPP
  • .CS
  • .H
  • .PHP
  • .ASP
  • .RB
  • .JAVA
  • .JAR
  • .CLASS
  • .AAF
  • .AEP
  • .AEPX
  • .PLB
  • .PREL
  • .PRPROJ
  • .AET
  • .PPJ
  • .PSD
  • .INDD
  • .INDL
  • .INDT
  • .INDB
  • .INX
  • .IDML
  • .PMD
  • .XQX
  • .XQX
  • .AI
  • .EPS
  • .PS
  • .SVG
  • .SWF
  • .FLA
  • .AS3
  • .AS
  • .TXT
  • .DOC
  • .DOT
  • .DOCX
  • .DOCM
  • .DOTX
  • .DOTM
  • .DOCB
  • .RTF
  • .WPD
  • .WPS
  • .MSG
  • .PDF
  • .XLS
  • .XLT
  • .XLM
  • .XLSX
  • .XLSM
  • .XLTX
  • .XLTM
  • .XLSB
  • .XLA
  • .XLAM
  • .XLL
  • .XLW
  • .PPT
  • .POT
  • .PPS
  • .PPTX
  • .PPTM
  • .POTX
  • .POTM
  • .PPAM
  • .PPSX
  • .PPSM
  • .SLDX
  • .SLDM
  • .WAV
  • .MP3
  • .AIF
  • .IFF
  • .M3U
  • .M4U
  • .MID
  • .MPA
  • .WMA
  • .RA
  • .AVI
  • .MOV
  • .MP4
  • .3GP
  • .MPEG
  • .3G2
  • .ASF
  • .ASX
  • .FLV
  • .MPG
  • .WMV
  • .VOB
  • .M3U8
  • .CSV
  • .EFX
  • .SDF
  • .VCF
  • .XML
  • .SES

It renames encrypted files using the following names:

  • {original file name and file extension}.cerber

It does the following:

    • It avoids encrypting files on the directories that contain the following strings
    • Windows
    • Program Files
    • Program Files (x86)
    • games
    • packages
    • AppData
    • Application Data
    • cache
    • temp
    • PerfLogs
    • Windows

It gathers the following information and reports it to its servers:

  • volume serial number

NOTES:

This ransomware shows the following ransom note:

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 12.886.03
FIRST VSAPI PATTERN DATE: 08 Nov 2016
VSAPI OPR PATTERN File: 12.887.00
VSAPI OPR PATTERN Date: 09 Nov 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

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • Traxxio = "%Application Data\{original file name and file extension}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_LOCALMACHINE_LOCKDOWN
    • iexplore.exe = "0"

Step 5

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.
  • %Desktop%\HOW_TO_RESTORE_YOUR_DATA.html
  • %Application Data%\HOW_TO_RESTORE_YOUR_DATA.html
  • {folders where it is able to encrypt files}\HOW_TO_RESTORE_YOUR_DATA.html

Step 6

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

Restore encrypted files from backup.


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