RANSOM_DEMOCRY.SM

June 04, 2016
 Analysis by: Francis Xavier Antazo
 ALIASES:

Ransom:Win32/SieteCrypto.A (Microsoft); a variant of Win32/Filecoder.NGQ (ESET); Trojan-Ransom.Win32.Democry.a (Kaspersky);

 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

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.

  TECHNICAL DETAILS

File Size:

1,197,190 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

12 May 2016

Payload:

Encrypts files, 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 component file(s):

  • %Desktop%\read_this_file.txt - ransom note
  • %User Temp%\tmp.bmp

(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 Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp 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.)

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

  • FOR DECRYPT FILES
    SEND ONE FILE IN EMAIL
    {BLOCKED}aiver@aol.com

Other Details

This Trojan renames encrypted files using the following names:

  • (original file name and extension)._{date}-{time}_{BLOCKED}aiver@aol.com$.777

It does the following:

  • It avoids encrypting on the following file paths:
    • %Windows%
    • %Program Files%
    • %User Temp%
  • It avoids encrypting files with the following file extensions:
    • .exe
    • .777
    • .dll
    • .msi
  • It only works on the following date:
    May 01 - 15

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp 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.)

NOTES:

This malware displays the following message box when it is executed on the system:

It displays the following message box if it successfully encrypts the system:

It sets the file %User Temp%\tmp.bmp as wallpaper:

  SOLUTION

Minimum Scan Engine:

9.800

VSAPI OPR PATTERN File:

12.545.00

VSAPI OPR PATTERN Date:

23 May 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 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.  
  • %Desktop%\read_this_file.txt - ransom note
  • %User Temp%\tmp.bmp

Step 4

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