Analysis by: John Kevin Sanchez

ALIASES:

Backdoor.Rokrat (Symantec), Troj.W32.Rockrat!c (AegisLab), Trojan.RockRat.a (Jiangmin)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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 executes then deletes itself afterward.

It connects to certain websites to send and receive information.

  TECHNICAL DETAILS

File Size: 626,688 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 02 Feb 2018

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:

  • {8 hex characters}.tmp -> screenshot of the affected system
  • {Random Number}.dat -> (deleted afterwards)

It adds the following processes:

  • wscript.exe

It executes then deletes itself afterward.

Other Details

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

  • https://{BLOCKED}i.{BLOCKED}d.com
  • https://{BLOCKED}i.{BLOCKED}x.com
  • https://{BLOCKED}i.{BLOCKED}xapi.com
  • https://{BLOCKED}i.{BLOCKED}x.net

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 13.952.04
FIRST VSAPI PATTERN DATE: 07 Feb 2018
VSAPI OPR PATTERN File: 13.953.00
VSAPI OPR PATTERN Date: 08 Feb 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

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.  
  • {8 hex characters}.tmp
  • {Random Number}.dat

Step 4

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_KORPODE.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 this Knowledge Base page for more information.


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