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RANSOM_CRYPTOBIT.A

April 30, 2016
 Analysis by: Jennifer Gumban
 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • 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 modifies the Internet Explorer Zone Settings.

It connects to certain websites to send and receive information.

  TECHNICAL DETAILS

File Size:

124,416 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

26 Apr 2016

Payload:

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:

  • {folders containing encrypted files}\sekretzbel0ngt0us.KEY
  • %Application Data%\{8 numbers} - contains the list of files encrypted
  • {folders containing encrypted files}\OKSOWHATHAPPENDTOYOURFILES.TXT - ransomnote

(Note: %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.)

Web Browser Home Page and Search Page Modification

This Trojan modifies the Internet Explorer Zone Settings.

Other Details

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

  • http://{BLOCKED}rome69.net/knock.php?id=58903347
  • http://{BLOCKED}0.{BLOCKED}4.241.151:80

It encrypts files with the following extensions:

  • .mht
  • .zip
  • .dvr-ms
  • .wvx
  • .wmx
  • .wmv
  • .wm
  • .mpv2
  • .mpg
  • .mpeg
  • .mpe
  • .mpa
  • .mp2v
  • .mp2
  • .m1v
  • .IVF
  • .asx
  • .asf
  • .wax
  • .snd
  • .rmi
  • .m3u
  • .au
  • .aiff
  • .aifc
  • .aif
  • .midi
  • .mid
  • .wma
  • .wav
  • .mp3
  • .wmf
  • .tiff
  • .tif
  • .rle
  • .png
  • .jpeg
  • .jpe
  • .jpg
  • .jfif
  • .ico
  • .gif
  • .emf
  • .dib
  • .bmp
  • .docx
  • .pptx
  • .pptx
  • .xlsx
  • .xlsx
  • .xbap
  • .xbap
  • .xps
  • .xps
  • .pdf
  • .pdf
  • .pot
  • .pot
  • .hta
  • .xlt
  • .xlt
  • .pps
  • .pps
  • .xlw
  • .xlw
  • .dot
  • .dot
  • .rtf
  • .rtf
  • .ppt
  • .ppt
  • .xls
  • .xls
  • .doc
  • .doc
  • .xml
  • .xml
  • .htm
  • .html
  • .html
  • .htm
  • .hta

NOTES:

It avoids encrypting files within the following folder:

  • gamemedia
  • application
  • system
  • compressed
  • video
  • text
  • document
  • audio
  • image

It avoids encrypting files with the following extensions:

    .vb
  • .scr
  • .reg
  • .pif
  • .msi
  • .lnk
  • .cpl
  • .com
  • .cmd
  • .bat
  • .bas

The ransomnote displays the ff:

Your ID: {8 numbers}
* * *
Hi. Your files are now encrypted. I have the key to decrypt them back.
I will give you a decrypter if you pay me. If you pay me today, the price is only 1 bitcoin.
If you pay me tomorrow, you will have to pay 2 bitcoins. If you pay me one week later the price
will be 7 bitcoins and so on. So, hurry up.

Contact me using this email address: {BLOCKED}acker@india.com
If you don't get a reply or if the email dies, then contact me using Bitmessage:
download it form here https://github.com/mailchuck/PyBitmessage/releases/download/v0.5.8/Bitmessage-0.5.8.exe
Run it, click New Identity and then send me a message at {BLOCKED}p1xZMRQpeU5svwg2

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

12.490.05

FIRST VSAPI PATTERN DATE:

26 Apr 2016

VSAPI OPR PATTERN File:

12.491.00

VSAPI OPR PATTERN Date:

27 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

Identify and terminate files detected as RANSOM_CRYPTOBIT.A

[ Learn More ]
  1. 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.
  2. 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.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

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.  
  • sekretzbel0ngt0us.KEY
  • OKSOWHATHAPPENDTOYOURFILES.TXT

Step 5

Reset Internet security settings

[ Learn More ]

Step 6

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


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