WORM_DORKBOT.P

 Analysis by: Erika Bianca Mendoza
 Modified by: Michael Cabel

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

This worm arrives by connecting affected removable drives to a system. It may be unknowingly downloaded by a user while visiting malicious websites.

It is injected into all running processes to remain memory resident.

It drops copies of itself in all removable drives. It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

It connects to Internet Relay Chat (IRC) servers.

It performs denial of service (DoS) attacks on affected systems using specific flooding method(s).

It prevents users from visiting antivirus-related websites that contain specific strings.

  TECHNICAL DETAILS

File Size:

114,688 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

17 Aug 2011

Payload:

Performs denial of service attacks, Connects to URLs/IPs

Arrival Details

This worm arrives by connecting affected removable drives to a system.

It may be unknowingly downloaded by a user while visiting malicious websites.

Installation

This worm drops the following component file(s):

  • {removable drive}\recycler.lnk

It creates the following folders:

  • {removable drive}\RECYCLER

It is injected into all running processes to remain memory resident.

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • 1LSJuVlZPsaJ3FWT

Autostart Technique

This worm adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{Malware File Name} = {Malware Path and File Name}

Propagation

This worm drops copies of itself in all removable drives.

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

The said .INF file contains the following strings:

[autorun]
;{Random String}
shellexecute={Malware Path and File Name}
;{Random String}
action=Open folder to view files
;{Random String}
useautoplay=1
;{Random String}
icon=shell32.dll,7
;{Random String}
shell\explore\command={Malware Path and File Name}
;{Random String}
shell\open\command={Malware Path and File Name}

It sends copies of itself to target recipients using the following instant-messaging (IM) applications:

  • MSN
  • Pidgin
  • Windows Live Messenger

Backdoor Routine

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

  • {BLOCKED}enial.com
  • {BLOCKED}ebsite.com
  • {BLOCKED}ctronix.com
  • {BLOCKED}s.com

Denial of Service (DoS) Attack

This worm performs denial of service (DoS) attacks on affected systems using the following flooding method(s):

  • Slowloris Flood
  • UDP Flood
  • SYN Flood

Other Details

This worm connects to the following URL(s) to get the affected system's IP address:

  • http://api.wipmania.com

It prevents users from visiting antivirus-related websites that contain the following strings:

  • avast.
  • avira.
  • bitdefender.
  • bullguard.
  • clamav.
  • comodo.
  • emsisoft.
  • eset.
  • f-secure.
  • fortinet.
  • garyshood.
  • gdatasoftware.
  • heck.tc
  • iseclab.
  • jotti.
  • kaspersky.
  • lavasoft.
  • malwarebytes.
  • mcafee.
  • norman.
  • norton.
  • novirusthanks.
  • onecare.live.
  • onlinemalwarescanner.
  • pandasecurity.
  • precisesecurity.
  • sophos.
  • sunbeltsoftware.
  • symantec
  • threatexpert.
  • trendmicro.
  • virscan.
  • virus.
  • virusbuster.nprotect.
  • viruschief.
  • virustotal.
  • webroot.
  • avast.
  • avira.
  • bitdefender.
  • bullguard.
  • clamav.
  • comodo.
  • emsisoft.
  • eset.
  • f-secure.
  • fortinet.
  • garyshood.
  • gdatasoftware.
  • heck.tc
  • iseclab.
  • jotti.
  • kaspersky.
  • lavasoft.
  • malwarebytes.
  • mcafee.
  • norman.
  • norton.
  • novirusthanks.
  • onecare.live.
  • onlinemalwarescanner.
  • pandasecurity.
  • precisesecurity.
  • sophos.
  • sunbeltsoftware.
  • symantec
  • threatexpert.
  • trendmicro.
  • virscan.
  • virus.
  • virusbuster.nprotect.
  • viruschief.
  • virustotal.
  • webroot.

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

8.360.13

FIRST VSAPI PATTERN DATE:

17 Aug 2011

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Scan your computer with your Trend Micro product and note files detected as WORM_DORKBOT.P

Step 3

Restart in Safe Mode

[ Learn More ]

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\Software\Microsoft\Windows\CurrentVersion\Run
    • {Malware File Name} = {Malware Path and File Name}

Step 5

Search and delete this folder

[ 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. {Removable Drive}\RECYCLER

Step 6

Search and delete AUTORUN.INF files created by WORM_DORKBOT.P that contain these strings

[ Learn More ]
[autorun]
;{Random String}
shellexecute={Malware Path and File Name}
;{Random String}
action=Open folder to view files
;{Random String}
useautoplay=1
;{Random String}
icon=shell32.dll,7
;{Random String}
shell\explore\command={Malware Path and File Name}
;{Random String}
shell\open\command={Malware Path and File Name}

Step 7

Search and delete these files

[ Learn More ]
There may be some component files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
{Removable Drive}\recycler.lnk

Step 8

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


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