Analysis by: Marvelous Pelin

 ALIASES:

Ransom.Alcatraz(Malwarebytes)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 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 ransomware, also known as Alcatraz Locker, charges its victims between 0.3 - 0.5 bitcoin to decrypt files. It also adds the .alcatraz to files it encrypts.

To get a one-glance comprehensive view of the behavior of this Trojan, refer to the Threat Diagram shown below.

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 is capable of encrypting files in the affected system.

  TECHNICAL DETAILS

File Size: 117,760 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 31 Oct 2016
Payload: Encrypts files, Connects to URLs/IPs, Displays message/message boxes

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:

  • %Desktop%\ransomed.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.)

Other Details

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

  • http://www.myexternalip.com/raw

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

  • {BLOCKED}.{BLOCKED}.83.197
  • http://{BLOCKED}ejnmvdf2.onion.to

It renames encrypted files using the following names:

  • {original filename}.Alcatraz

It does the following:

  • It deletes shadow copies by executing the following command:
    • vssadmin.exe Delete Shadows /Quiet /All
  • It displays the Ransom note using the following commands:
    • C:\Windows\system32\cmd.exe /c start %Desktop%\ransomed.html
  • It avoids encrypting files in the AppData folder.
  • It only encrypts files in the %User Profile%.

(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.. %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)

It is capable of encrypting files in the affected system.

NOTES:

This ransomware uses the following ransom note:

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 12.870.05
FIRST VSAPI PATTERN DATE: 31 Oct 2016
VSAPI OPR PATTERN File: 12.871.00
VSAPI OPR PATTERN Date: 01 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

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%\ransomed.html

Step 4

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