Analysis by: Christian Noel Olalia

ALIASES:

Trojan.Gen.2 (NORTON); Trojan.Generic.21786331 (BITDEFENDER); RDN/Ransom (NAI)

 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, Downloaded from the Internet

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.

However, due to errors in its code, it fails to perform its intended routine.

It encrypts files found in specific folders.

  TECHNICAL DETAILS

File Size: 91,648 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 29 May 2017
Payload: Drops files

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.

Other Details

This Ransomware encrypts files with the following extensions:

  • .txt
  • .pdf
  • .jpg
  • .jpeg

It drops the following file(s)/component(s):

  • %Desktop%\crypted_file.txt
  • %Desktop%\test\tuanlinh.rar

(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.)

However, due to errors in its code, it fails to perform its intended routine.

It does the following:

  • It executes the following WinRAR command:
    • WinRAR -mt2 a -inul -IBCK -ace -p=1234 -m1 -logf=""C:\Users\Tuan Linh\Desktop\crypted_file.txt"" ""C:\Users\Tuan Linh\Desktop\test\tuanlinh.rar"" ""C:\Users\*\*.txt""

Ransomware Routine

This Ransomware encrypts files found in the following folders:

  • %User Profile%

(Note: %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.)

NOTES:

However, as of this writing, this ransomware is still under development.

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 13.436.05
FIRST VSAPI PATTERN DATE: 29 May 2017
VSAPI OPR PATTERN File: 13.437.00
VSAPI OPR PATTERN Date: 30 May 2017

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%\crypted_file.txt
  • %Desktop%\test\tuanlinh.rar

Step 4

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

Step 5

Restore encrypted files from backup.


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