Analysis by: Anthony Joe Melgarejo
 Modified by: Neljorn Nathaniel Aguas
ALIASES:

Backdoor:Perl/Shellbot.S (MICROSOFT)

 PLATFORM:

Windows, Linux

 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: Downloaded from the Internet, Dropped by other malware

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 connects to Internet Relay Chat (IRC) servers. It joins an Internet Relay Chat (IRC) channel. It executes commands from a remote malicious user, effectively compromising the affected system.

  TECHNICAL DETAILS

File Size: 29601 bytes
File Type: Other
Memory Resident: No
Initial Samples Received Date: 16 Sep 2010
Payload: Connects to URLs/IPs, Executes commands

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.

Backdoor Routine

This Backdoor connects to any of the following Internet Relay Chat (IRC) servers:

  • {BLOCKED}.{BLOCKED}.{BLOCKED}.23:443

It joins any of the following Internet Relay Chat (IRC) channels:

  • #seul

It executes the following commands from a remote malicious user:

  • Launch DDoS attacks
  • Perform port scanning
  • Execute reverse shells
  • Download files
  • Send emails
  • Retrieve system information
  • Exploit kernel vulnerabilities
  • Manage bot:
    • Toggle attack statistics
    • Change the bot's IRC nickname
    • Terminate the bot
    • Join/leave IRC channels

Other Details

This Backdoor connects to the following possibly malicious URL:

  • http://{BLOCKED}y.ru/xpl

It does the following:

  • It masquerades itself as a legitimate process under any of the following process names at random:
    • /usr/lib/systemd/systemd-logind
    • /sbin/init
    • /usr/sbin/ipmaddr
    • /usr/sbin/saslauthd
    • /sbin/syslogd
    • /sbin/tcpslice

  SOLUTION

Minimum Scan Engine: 9.700
FIRST VSAPI PATTERN FILE: 11.186.06
FIRST VSAPI PATTERN DATE: 02 Oct 2014
VSAPI OPR PATTERN File: 11.187.00
VSAPI OPR PATTERN Date: 03 Oct 2014

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

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