Analysis by: Anthony Joe Melgarejo
ALIASES:

Linux.Darlloz (Symantec), Linux/Darlloz.A worm (ESET)

 PLATFORM:

Linux

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel: Propagates via network shares

This worm exploits software vulnerabilities to propagate to other computers across a network.

  TECHNICAL DETAILS

File Size: 71,392 bytes
File Type: ELF
Memory Resident: No
Initial Samples Received Date: 28 Nov 2013
Payload: Terminates processes

Arrival Details

This worm may arrive via network shares.

Installation

This worm drops the following copies of itself into the affected system:

  • /tmp/x86

It creates the following folders:

  • /var/run/.zollard/

Other System Modifications

This worm deletes the following files:

  • /var/run/.lightscan
  • /var/run/lightscan
  • /var/run/mipsel
  • /var/run/mips
  • /var/run/sh
  • /var/run/arm
  • /var/run/ppc
  • /var/run/m
  • /var/run/mi
  • /var/run/s
  • /var/run/a
  • /var/run/p
  • /var/run/msx
  • /var/run/mx
  • /var/run/sx
  • /var/run/ax
  • /var/run/px
  • /var/run/32
  • /var/run/sel
  • /var/run/pid
  • /var/run/gcc
  • /var/run/dev
  • /var/run/psx
  • /var/run/mpl
  • /var/run/mps
  • /var/run/sph
  • /var/run/arml
  • /var/run/mips.l
  • /var/run/mipsell
  • /var/run/ppcl
  • /var/run/shl
  • /bin/pp
  • /bin/mi
  • /bin/mii
  • /var/tmp/dreams.install.sh
  • /var/tmp/ep2.ppc
  • /usr/bin/wget
  • /usr/bin/-wget

Propagation

This worm exploits the following software vulnerabilities to propagate to other computers across a network:

  • CVE-2013-1823

Process Termination

This worm terminates the following processes if found running in the affected system's memory:

  • telnetd

NOTES:

This malware generates random IP addresses and attempts to access them. If an accessible IP address is found, it attempts to access the following directories:

  • /cgi-bin/php
  • /cgi-bin/php5
  • /cgi-bin/php-cgi
  • /cgi-bin/php.cgi
  • /cgi-bin/php4

It uses the following list of user names and passwords to access the locations mentioned above in case they are password-protected:

  • root
  • 1234
  • 12345
  • dreambox
  • smcadmin

It loads the following modules (iptables):

  • /lib/modules/{kernel version}/kernel/net/ipv4/netfilter/ip_tables.ko
  • /lib/modules/{kernel version}/kernel/net/ipv4/netfilter/iptable_filter.ko

It drops TCP packets on port 23. As a result, telnet communications are blocked in the affected system.

It terminates and deletes the following processes and files:

  • /var/run/.lightpid
  • /var/run/.aidrapid
  • /var/run/lightpid

  SOLUTION

Minimum Scan Engine: 9.700
FIRST VSAPI PATTERN FILE: 10.440.07
FIRST VSAPI PATTERN DATE: 28 Nov 2013
VSAPI OPR PATTERN File: 10.441.00
VSAPI OPR PATTERN Date: 29 Nov 2013

Step 1

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

Step 2

Search and delete these folders

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • var/run/.zollard/

Step 3

Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.

  • /var/run/.lightpid
  • /var/run/.aidrapid
  • /var/run/lightpid
  • /var/run/.lightscan
  • /var/run/lightscan
  • /var/run/mipsel
  • /var/run/mips
  • /var/run/sh
  • /var/run/arm
  • /var/run/ppc
  • /var/run/m
  • /var/run/mi
  • /var/run/s
  • /var/run/a
  • /var/run/p
  • /var/run/msx
  • /var/run/mx
  • /var/run/sx
  • /var/run/ax
  • /var/run/px
  • /var/run/32
  • /var/run/sel
  • /var/run/pid
  • /var/run/gcc
  • /var/run/dev
  • /var/run/psx
  • /var/run/mpl
  • /var/run/mps
  • /var/run/sph
  • /var/run/arml
  • /var/run/mips.l
  • /var/run/mipsell
  • /var/run/ppcl
  • /var/run/shl
  • /bin/pp
  • /bin/mi
  • /bin/mii
  • /var/tmp/dreams.install.sh
  • /var/tmp/ep2.ppc
  • /usr/bin/wget
  • /usr/bin/-wget

Step 4

Download and apply these security patches Refrain from using these products until the appropriate patches have been installed. Trend Micro advises users to download critical patches upon release by vendors.

  • https://bugs.php.net/patch-display.php?bug_id=61910&patch=CVE-2012-1823.patch&revision=latest


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