Analysis by: Byron Jon Gelera
ALIASES:

PowerShell/TrojanDownloader.Agent.AEA (NOD32)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • 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.

  TECHNICAL DETAILS

File Size: 19,490 bytes
File Type: XML
Memory Resident: No
Initial Samples Received Date: 16 Feb 2018
Payload: Connects to URLs/IPs

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

The scheduled task executes the malware every:

  • Every day
  • Every 8 hours

Other System Modifications

This Trojan adds the following registry entries:

HKEY_CURRENT_USER\Console\%SystemRoot%_System32_WindowsPowerShell_v1.0_powershell.exe
WindowPosition = "201329664"

HKEY_CURRENT_USER\Console\%SystemRoot%_System32_svchost.exe
WindowPosition = "201329664"

HKEY_CURRENT_USER\Console\taskeng.exe
WindowPosition = "201329664"

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.

Other Details

This Trojan does the following:

  • Serves as a scheduled task capable of executing the following powershell commands at system startup or every 8 hours:
    • "%System%\WindowsPowerShell\v1.0\powershell.exe" -windowstyle hidden -noninteractive -ExecutionPolicy bypass -EncodedCommand {Base64 encoded powershell command}

    The base64 encoded powershell command is used to connect to the following URL to download a string data:
    • http://{BLOCKED}n.info/u/?q=YoT0Acc6d-ebAHbBkoc64usY-DORZVrMluMQsV2JwZlSOSCZmIUq7wzBmC1eaFjdAHziwUMi_SkZ591jUXDnNl9uDd8D4hBN3ko11-Wihyj4IAhAU9TuCHgykeKZgUUHeqyae231_30_XW7wvpyXQLWXYMhBsnsAAxRfU2y3-_-ES3QpqVK9uwIKYF14y0DpbBiWmmGr-xjjBDUue8zy4pwpWQ06J-69dzBmgQuc5L1lAKnabPiBQH44XCS5xdJB6VoJBW9ex5AJB8ymyNI9cumd_kNQx9DQQ1FltBnFxVv09tt6pO9qu_2H2akAUshIuEPbXMc8-VFgKFLtkWhbYVs29wHL_rVrVeUm_CsB3aoVG1kJBidB8FVF0nqQhvPtEXQ69Kdx67hJRwuae6a98CXALz0osHCn0OsDNHoeXgypw_TEg7Hj7mK5_fMr8IxgFDjUO_9ZMjA2yapDPEX1StWt&c=-1TPm8RMw2wtquh8O98IEm2dLGv90KKxlXkogG0WCwNWSW3ck3JR-VyWgnJAZmwPOn4lugGieG6Yj806mmeE_wQzgVlfCka08FxF6x3jkqvvgTq8DnT1Y-nRUOYMR4yVxiRAo_whr24ARJbh359z9E6WFW69i3J3HsARFM75DT6tS70cxdLNKgprijv8G2XRfcxneaG-oplQ5vR-is8Pua_bL3GRLfzCzBirCRdOr5e43hoOI0ZK0ykOgd-1KRkzG7sDLRHvL0ljz7iBiSFN5zxHGMerOi5dX9M6qQrlooY5hQuqZMf2ciUzH-cOINf3a0OavTvFtvUzHwknWzf9ujpCOR1nDSsxM1WEXXIWYxxKWCGlsN1xYDBjPuDcQuATokgjqCWs9QqmQpQn8DuDCPsyhFGZB--iWLDvBrCEiDkbAukzxyQmS6O7L-9QOgkQ_GrzKsHTfwiK8JdsNMh85iuLAEArdEbJQdJ3MoMZfoRZZCRCFhwNzbBAUt_tl74lQa0g16AwKyHDd2kh6BGLJmd23IezKSlAhi-TKukhwFuL77oDmj9RHSYuvmFWHrK0CDruBNJrsgfCcjIkdD7dHnIiHC59tXBRKqmtyQpHFMlgkNghb6cZOIBKBqdRNCjrPgUNeyl_Gn_Fc09zk71w9JhJf3PS2moPbVX&r=6288371604237158118

    The downloaded string will then be decoded and executed directly into memory.
    However, as of this writing, the said sites are inaccessible.
  • It will not proceed with its download routine if any of the following conditions is met:
    • Powershell version is less than 2
    • Operating System is Windows XP or Windows 2000 And service pack version is less than 2
    • If executed by Non-Admin

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 13.976.04
FIRST VSAPI PATTERN DATE: 19 Feb 2018
VSAPI OPR PATTERN File: 13.977.00
VSAPI OPR PATTERN Date: 20 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

Identify and terminate files detected as TROJ_POWECOD.AZ

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 4

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

 
  • In HKEY_CURRENT_USER\Console\%SystemRoot%_System32_WindowsPowerShell_v1.0_powershell.exe
    • WindowPosition = "201329664"
  • In HKEY_CURRENT_USER\Console\%SystemRoot%_System32_svchost.exe
    • WindowPosition = "201329664"
  • In HKEY_CURRENT_USER\Console\taskeng.exe
    • WindowPosition = "201329664"

Step 5

Scan your computer with your Trend Micro product to delete files detected as TROJ_POWECOD.AZ. 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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