Analysis by: Ryan Paolo Maglaque

 ALIASES:

MSIL/TeleDoor.A(Eset-NOD32);Backdoor.MSIL.TeleDoor.gen(Kaspersky);Backdoor.Telebot(Symantec)

 PLATFORM:

Windows

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

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

This Backdoor 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 commands from a remote malicious user, effectively compromising the affected system.

  TECHNICAL DETAILS

File Size: 5,161,984 bytes
File Type: DLL
Memory Resident: No
Initial Samples Received Date: 04 Jul 2017
Payload: Connects to URLs/IPs, Collects system information, Downloads files, Executes files

Arrival Details

This Backdoor 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 Backdoor adds the following mutexes to ensure that only one of its copies runs at any one time:

  • MeComDoWork

Backdoor Routine

This Backdoor executes the following commands from a remote malicious user:

  • Get a file from the infected machine
  • Get machine information(OS, admin rights, architecture)
  • Download files
  • Execute downloaded file
  • Execute shell commands

It connects to the following URL(s) to send and receive commands from a remote malicious user:

  • http://{BLOCKED}d.{BLOCKED}c.com.ua/last.ver?rnd={GUID}

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 13.512.06
FIRST VSAPI PATTERN DATE: 04 Jul 2017
VSAPI OPR PATTERN File: 13.513.00
VSAPI OPR PATTERN Date: 05 Jul 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

Scan your computer with your Trend Micro product to delete files detected as BKDR_TELEBOT.VBV. 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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