ELF_MASANAC.A

July 06, 2017
 ALIASES:

a variant of Linux/Agent.AJ (ESET)

 PLATFORM:

Linux

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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:

618,642 bytes

File Type:

ELF

Memory Resident:

Yes

Initial Samples Received Date:

17 Dec 2014

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 drops the following copies of itself into the affected system and executes them:

  • /boot/{random filename}

It drops the following component file(s):

  • /etc/cron.hourly/cron.sh
  • /etc/init.d/rc{random}

Other Details

This Trojan connects to the following possibly malicious URL:

  • {BLOCKED}.{BLOCKED}.9.228

It does the following:

  • It sets the following environment variables:
    • HOME=/
    • PATH = /bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin:/usr/X11R6/bin
    • MYSQL_HISTFILE=/dev/null
    • HISTFILE=/dev/null
  • It executes the following command:
    sed -i '/\etc\/cron.hourly\/cron.sh/d' /etc/crontab && echo '*3 * * * * root /etc/cron.hourly/cron.sh >> /etc/crontab

  SOLUTION

Minimum Scan Engine:

9.700

FIRST VSAPI PATTERN FILE:

11.350.01

FIRST VSAPI PATTERN DATE:

17 Dec 2014

Scan your computer with your Trend Micro product and note files detected as ELF_MASANAC.A

NOTES:

Identify and terminate the malware process using the noted path in the previous step.

  1. Open the Terminal. Access Applications>Accessories>Terminal or press CTRL + ALT then T.
  2. Type the following in the terminal:
    ps –A
  3. Look for the detected files and take note of their PIDs. If the detected files are not found to be running, please proceed to the next step.
  4. In the same terminal, enter the following commands for each PIDs:
    kill {PID}

Delete the malware files using the noted path and file name.

  1. In the same Terminal, type the following commands:
    sudo rm -R "/boot/{random file name}"sudo rm -R"/etc/cron.hourly/cron.sh"sudo rm -R "/etc/init.d/rc{random}"

Note that the file in /etc/init.d should contain the following content:
chkconfig: 12345 9090

If the files are not present, you may proceed to the next step.

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


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