Analysis by: Bren Matthew Ebriega
ALIASES:

AIT:Trojan.Autoit.RRS (BITDEFENDER)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet, Dropped by other malware

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: 167,458 bytes
File Type: AU3
Memory Resident: Yes
Initial Samples Received Date: 14 Sep 2020
Payload: Executes files, Others

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.

Other Details

This Trojan requires the following additional components to properly run:

  • {Malware File Path}\{three characters}ai.exe → Normal file
  • {Malware File Path}\{three charactersl}1.{reverse of three characters} → encrypted DLL file detected as Trojan.Win32.MISPADO.THENC

It does the following:

  • Loads and decrypts an embedded dll that will be used to decrypt and load {Malware File Path}\{three characters}1.{reverse of three characters}.
  • The decrypted {Malware File Path}\{three characters}1.{reverse of three characters} is detected as TrojanSpy.Win32.MISPADU.THIADBO.

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 16.228.06
FIRST VSAPI PATTERN DATE: 15 Sep 2020
VSAPI OPR PATTERN File: 16.229.00
VSAPI OPR PATTERN Date: 16 Sep 2020

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

Scan your computer with your Trend Micro product to delete files detected as Trojan.AutoIt.MISPADO.THIADBO. 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:


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