Analysis by: Christopher Daniel So
ALIASES:

Backdoor.Linux.Roopre.g (Kaspersky), ELF/Roopre-A (Sophos)

 PLATFORM:

Linux

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: Yes

  • 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 executes commands from a remote malicious user, effectively compromising the affected system. It connects to a website to send and receive information.

  TECHNICAL DETAILS

File Size: Varies
File Type: ELF
Memory Resident: Yes
Initial Samples Received Date: 08 Oct 2014
Payload: Compromises system security

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.

Installation

This backdoor drops the following files:

  • .cahed_sess

Backdoor Routine

This backdoor executes the following commands from a remote malicious user:

  • R - Refresh the session with C&C server
  • F - Download file drom C&C server
  • L - Set maximum number of threads and connection timeout, or load a shared library
  • S - Stop all threads executing the loaded shared library routines
  • G - Create threads to execute exported functions of loaded shared libraries

It connects to the following websites to send and receive information:

  • http://{BLOCKED}niels.net/mayhem.php

  SOLUTION

Minimum Scan Engine: 9.700
FIRST VSAPI PATTERN FILE: 11.198.02
FIRST VSAPI PATTERN DATE: 08 Oct 2014

Step 1

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

Step 2

Restart in normal mode and scan your computer with your Trend Micro product for files detected as ELF_ROOPRE.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.

NOTES:

To delete the file .cahed_sess, type the following commands in the terminal:

  • cd "{malware path}"
  • rm .cahed_sess


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