Trojan.Win32.NYMAIM.GFRX

April 05, 2019
 Analysis by: Noel Anthony Llimos
 ALIASES:

Trojan:Win32/Nymaim.YA (MICROSOFT)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

This Trojan connects to a website to send and receive information.

  TECHNICAL DETAILS

File Size:

670,720 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

22 Mar 2019

Installation

This Trojan drops the following files:

  • %User Temp%\{random folder name}\{random filename}.{random extension} - encrypted
  • %All Users Profile%\{random folder name}\{random filename}.{random extension} - encrypted

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, and 8.. %All Users Profile% is the common user's profile folder, which is usually C:\Documents and Settings\All Users on Windows 2000, XP, and Server 2003, or C:\ProgramData on Windows Vista, 7, and 8. )

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
{random}
{random name} = "{data}"

Backdoor Routine

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

  • http://d{BLOCKED}se.com/z{BLOCKED}i/index.php

Other Details

This Trojan connects to the following URL(s) to check for an Internet connection:

  • zepter.com
  • carfax.com

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

14.888.06

FIRST VSAPI PATTERN DATE:

22 Mar 2019

VSAPI OPR PATTERN File:

14.889.00

VSAPI OPR PATTERN Date:

23 Mar 2019

Step 1

Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 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

Restart in Safe Mode

[ Learn More ]

Step 4

Delete this registry key

[ 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\{random}
    • {random name} = "{data}"

Step 5

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.  
  • %User Temp%\{random folder name}\{random filename}.{random extension} - encrypted
  • %All Users Profile%\{random folder name}\{random filename}.{random extension} - encrypted

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Trojan.Win32.NYMAIM.GFRX. 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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