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RANSOM_HIDDENTEARKOKO.A

January 05, 2017
 Analysis by: Janus Agcaoili
 ALIASES:

Ransom.HiddenTear (Malwarebytes), a variant of MSIL/Filecoder.DS (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

Infection Channel:

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 is capable of encrypting files in the affected system.

  TECHNICAL DETAILS

File Size:

40,960 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

25 Dec 2016

Payload:

Connects to URLs/IPs, Steals information, 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.

Other Details

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

  • http://tools.{BLOCKED}n.it/php/ip.php

It encrypts files with the following extensions:

  • .3dm
  • .3g2
  • .3gp
  • .aaf
  • .accdb
  • .aep
  • .aepx
  • .aet
  • .ai
  • .aif
  • .arw
  • .as
  • .as3
  • .asf
  • .asp
  • .asx
  • .avi
  • .bay
  • .bmp
  • .cdr
  • .cer
  • .class
  • .cpp
  • .cr2
  • .crt
  • .crw
  • .cs
  • .csv
  • .db
  • .dbf
  • .dcr
  • .der
  • .dng
  • .doc
  • .docb
  • .docm
  • .docx
  • .dot
  • .dotm
  • .dotx
  • .dwg
  • .dxf
  • .dxg
  • .efx
  • .eps
  • .erf
  • .fla
  • .flv
  • .idml
  • .iff
  • .indb
  • .indd
  • .indl
  • .indt
  • .inx
  • .jar
  • .java
  • .jpeg
  • .jpg
  • .kdc
  • .m3u
  • .m3u8
  • .m4u
  • .max
  • .mdb
  • .mdf
  • .mef
  • .mid
  • .mov
  • .mp3
  • .mp4
  • .mpa
  • .mpeg
  • .mpg
  • .mrw
  • .msg
  • .nef
  • .nrw
  • .odb
  • .odc
  • .odm
  • .odp
  • .ods
  • .odt
  • .orf
  • .p12
  • .p7b
  • .p7c
  • .pdb
  • .pdf
  • .pef
  • .pem
  • .pfx
  • .php
  • .plb
  • .pmd
  • .pot
  • .potm
  • .potx
  • .ppam
  • .ppj
  • .pps
  • .ppsm
  • .ppsx
  • .ppt
  • .pptm
  • .pptx
  • .prel
  • .prproj
  • .ps
  • .psd
  • .pst
  • .ptx
  • .r3d
  • .ra
  • .raf
  • .rar
  • .raw
  • .rb
  • .rtf
  • .rw2
  • .rwl
  • .sdf
  • .sldm
  • .sldx
  • .sql
  • .sr2
  • .srf
  • .srw
  • .svg
  • .swf
  • .tif
  • .vcf
  • .vob
  • .wav
  • .wb2
  • .wma
  • .wmv
  • .wpd
  • .wps
  • .x3f
  • .xla
  • .xlam
  • .xlk
  • .xll
  • .xlm
  • .xls
  • .xlsb
  • .xlsm
  • .xlsx
  • .xlt
  • .xltm
  • .xltx
  • .xlw
  • .xml
  • .xqx
  • .zip
  • .txt

It renames encrypted files using the following names:

  • {Original File path and File name}.kokolocker

It does the following:

  • Gathers the following Information:
    • Computer Name
    • User Name
    • Current Status (Locked\Unlocked)
    • IP Address
    • Inputted BitCoin Address
  • Encrypts files from the following folder(s):
    • C:\Batch
  • Displays the following GUI:

It is capable of encrypting files in the affected system.

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

13.116.02

FIRST VSAPI PATTERN DATE:

25 Dec 2016

VSAPI OPR PATTERN File:

13.117.00

VSAPI OPR PATTERN Date:

26 Dec 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_HIDDENTEARKOKO.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

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