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RANSOM_HOLA.B

March 09, 2018
 Analysis by: Michael Jhon Ofiaza
 ALIASES:

Trojan-Ransom.Win32.Cryakl.aqi (Kaspersky) ; Ransom.CryptXXX (Norton) ; Trojan:Win32/Bluteal!rfn (Microsoft)

 PLATFORM:

Windows

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

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Dropped by other malware

This Ransomware 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 a website to send and receive information.

  TECHNICAL DETAILS

File Size:

407,040 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

12 Jan 2018

Payload:

Connects to URLs/IPs

Arrival Details

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

  • 3548897987879

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{10 random numbers} = %User Temp%\{Malware Name}.exe

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{Random Numbers} = {Random Numbers}

Backdoor Routine

This Ransomware connects to the following websites to send and receive information:

  • http://{BLOCKED}srainbow.{BLOCKED}/cgi-sys/suspendedpage.cgi?vers=CL%201.4.0.0&id=2326257383-3@8@2018%205@34@17%20PM1184005&sender=
  • http://{BLOCKED}srainbow.{BLOCKED}/wp-content/themes/betheme/most.php?vers=CL%201.4.0.0&id=2326257383-3@8@2018%205@34@17%20PM1184005&sender=

Other Details

This Ransomware does the following:

  • It avoids encrypting files with the following extensions.
    • .bin
    • .com
    • .exe
    • .bat
    • .png
    • .bmp
    • .dat
    • .log
    • .ini
    • .dll
    • .sys

Ransomware Routine

This Ransomware renames encrypted files using the following names:

  • email-hola@all-ransomware.info.ver-CL 1.4.0.0.id-{ID number}-{Month in Number}@{Day}@{Year} {Hour}@{Minute}@{Second} {AM/PM}{7 Random Number}.fname-{File Name}.{File Extension}.fairytail

It leaves text files that serve as ransom notes containing the following text:

  • {Encrypted Folder}\README.txt

    ATTENTION!
    All your files are encrypted with cryptographically strong algorithm, and without original decryption key recovery is impossible.
    To get your unique key and decode files, you need to write us at email written below during 72 hours, otherwise your files will be destroyed forever!
    {BLOCKED}@{BLOCKED}nsomware.info
    {BLOCKED}@{BLOCKED}nsomware.info
    [BLOCKED}@{BLOCKED}nsomware.info

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.906.03

FIRST VSAPI PATTERN DATE:

15 Jan 2018

VSAPI OPR PATTERN File:

13.907.00

VSAPI OPR PATTERN Date:

16 Jan 2018

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

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
    • {10 random numbers} = %User Temp%\{Malware Name}.exe
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • {Random Numbers} = {Random Numbers}

Step 4

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.
  • {Encrypted Folder}\README.txt

Step 5

Scan your computer with your Trend Micro product to delete files detected as RANSOM_HOLA.B. 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 the following Trend Micro Support pages for more information:

Step 6

Restore encrypted files from backup.


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