Analysis by: Joachim Suico

ALIASES:

Trojan.Generic.13150825 (Bitdefender); Trojan horse Downloader.MSIL.AMBK (AVG); Trojan.Gen (Norton)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • 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: 38,400 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 02 Jun 2015
Payload: Downloads files

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.

Autostart Technique

This Trojan drops the following shortcut pointing to its copy in the User Startup folder to enable its automatic execution at every system startup:

  • Update.lnk

Dropping Routine

This Trojan drops the following files:

  • {malware path}\acc_done.txt
  • {malware path}\coin_done.txt
  • {malware path}\last_click.txt

Download Routine

This Trojan connects to the following URL(s) to download its configuration file:

  • www.pastebin.com

It saves the files it downloads using the following names:

  • {malware path}\coinurl.txt

Other Details

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

  • www.google.com

NOTES:

It monitors the list of processes and checks for the presence of the following string:

  • chrome

If the string is found, it connects to websites listed in the configuration file.

It renames the original malware file to {malware path}\df-coinurl.exe.

It monitors the list of processes for the following string to ensure that only a single instance of it is running:

  • df-coinurl

  SOLUTION

Minimum Scan Engine: 9.750
FIRST VSAPI PATTERN FILE: 11.654.04
FIRST VSAPI PATTERN DATE: 13 Apr 2015
VSAPI OPR PATTERN File: 11.655.00
VSAPI OPR PATTERN Date: 14 Apr 2015

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

Restart in Safe Mode

[ Learn More ]

Step 4

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.
  • {malware path}\acc_done.txt
  • {malware path}\coin_done.txt
  • {malware path}\last_click.txt
  • {malware path}\coinurl.txt
  • %User Startup%\Update.lnk

Step 5

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


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