Analysis by: Karl Dominguez
 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

Infection Channel: Propagates via flashdrives, Propagates via instant messaging applications

This description is based on a compiled analysis of several variants of WORM_DORKBOT. Note that specific data such as file names and registry values may vary for each variant.

This worm arrives via removable drives. It may be downloaded by other malware/grayware/spyware from remote sites. It may be dropped by other malware. It may be unknowingly downloaded by a user while visiting malicious websites.

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

It also has rootkit capabilities, which enables it to hide its processes and files from the user.

It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size: Varies
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 10 Mar 2011
Payload: Drops files, Connects to URLs/IPs

Arrival Details

This worm arrives via removable drives.

It may be downloaded by other malware/grayware/spyware from remote sites.

It may be dropped by other malware.

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

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} = "%User Profile%\Application Data\{malware file name}.exe"

Propagation

This worm creates the following folders in all removable drives:

  • {drive letter}:\RECYCLER

It drops the following copy(ies) of itself in all removable drives:

  • {drive letter}:\RECYCLER\{random characters}.exe

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]
;{garbage characters}
shellexecute=RECYCLER\{malware file name}.exe
;{garbage characters}
icon=shell32.dll,7
;{garbage characters}
shell\open\command=RECYCLER\{malware file name}.exe
;{garbage characters}
action=Open folder to view files
;{garbage characters}
shell\explore\command=RECYCLER\{malware file name}.exe
;{garbage characters}
useautoplay=1

It sends messages that contain links to sites hosting remote copies of itself using the following instant-messaging (IM) applications:

  • Windows Live Communicator
  • MSN Messenger
  • Pidgin
  • Xchat
  • mIRC

Backdoor Routine

This worm connects to the following URL(s) to send and receive commands from a remote malicious user:

  • {BLOCKED}ebsite.com
  • {BLOCKED}rebitch.com
  • {BLOCKED}ney.biz
  • {BLOCKED}ousez11.com
  • {BLOCKED}g.{BLOCKED}oan.com
  • {BLOCKED}g.{BLOCKED}opperz11.com
  • {BLOCKED}g.{BLOCKED}ousez11.com
  • {BLOCKED}g.{BLOCKED}allone.com
  • {BLOCKED}g.{BLOCKED}ketbaby.com
  • {BLOCKED}s.com
  • {BLOCKED}ussy.info
  • {BLOCKED}ctronix.com
  • {BLOCKED}enial.com
  • {BLOCKED}m.{BLOCKED}ch.ru
  • {BLOCKED}g.{BLOCKED}ousez11.com

Rootkit Capabilities

This worm also has rootkit capabilities, which enables it to hide its processes and files from the user.

Other Details

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

  • http://api.wipmania.com/

It deletes the initially executed copy of itself

NOTES:
This worm monitors the Internet activities of the infected system to steal user credentials if the user visits websites with the following strings:

  • *&Password=*
  • *&txtPassword=*
  • *.alertpay.*/*login.aspx
  • *.moneybookers.*/*login.pl
  • *1and1.com/xml/config*
  • *4shared.com/login*
  • *:2083/login*
  • *:2086/login*
  • *alertpay.com/login*
  • *aol.*/*login.psp*
  • *bcointernacional*login*
  • *bigstring.*/*index.php*
  • *depositfiles.*/*/login*
  • *dotster.com/*login*
  • *dyndns*/account*
  • *enom.com/login*
  • *facebook.*/login.php*
  • *fastmail.*/mail/*
  • *fileserv.com/login*
  • *fileserve.*/login*
  • *filesonic.com/*login*
  • *FLN-Password=*
  • *freakshare.com/login*
  • *gmx.*/*FormLogin*
  • *godaddy.com/login*
  • *google.*/*ServiceLoginAuth*
  • *hackforums.*/member.php
  • *hotfile.com/login*
  • *letitbit.net*
  • *login.live.*/*post.srf*
  • *login.yahoo.*/*login*
  • *login_password=*
  • *loginUserPassword=*
  • *mediafire.com/*login*
  • *megaupload.*/*login
  • *megaupload.*/*login*
  • *members*.iknowthatgirl*/members*
  • *members.brazzers.com*
  • *moniker.com/*Login*
  • *namecheap.com/*login*
  • *netflix.com/*ogin*
  • *netload.in/index*
  • *no-ip*/login*
  • *officebanking.cl/*login.asp*
  • *oron.com/login*
  • *pass=*
  • *passwd=*
  • *password=*
  • *password]=*
  • *paypal.*/webscr?cmd=_login-submit*
  • *runescape*/*weblogin*
  • *screenname.aol.*/login.psp*
  • *secure.logmein.*/*logincheck*
  • *sendspace.com/login*
  • *service=youtube*
  • *signin.ebay*SignIn
  • *sms4file.com/*/signin-do*
  • *speedyshare.com/login*
  • *steampowered*/login*
  • *TextfieldPassword=*
  • *thepiratebay.org/login*
  • *torrentleech.org/*login*
  • *twitter.com/sessions
  • *uploaded.to/*login*
  • *uploading.com/*login*
  • *vip-file.com/*/signin-do*
  • *webnames.ru/*user_login*
  • *what.cd/login*
  • *youporn.*/login*
  • Email
  • EmailName
  • FLN-Password
  • FLN-UserName
  • login
  • login_email
  • login_password
  • loginId
  • loginUserName
  • loginUserPassword
  • Passwd
  • Password
  • quick_password
  • quick_username
  • screenname
  • session[password]
  • session[username_or_email]
  • TextfieldEmail
  • TextfieldPassword
  • txtEmail
  • txtPassword
  • username
It attempts to steal user credentials used in the following websites:
  • AlertPay
  • AOL
  • BigString
  • DynDNS
  • Facebook
  • Fastmail
  • FileServe
  • Gmail
  • GMX
  • Hackforums
  • LogMeIn
  • Megaupload
  • Moneybookers
  • No-IP
  • NoIP
  • OfficeBanking
  • PayPal
  • Runescape
  • Steam
  • Twitter
  • Windows Live
  • Yahoo
  • Yahoo!
  • YouTube
It has the following backdoor capabilities:
  • Block DNS
  • Create processes
  • Download other files
  • Insert iframe tags into HTML files
  • Join an IRC channel
  • Log in to FTP sites
  • Perfrom Slowloris, UDP, and SYN flooding
  • Run Reverse Socks4 proxy server
  • Send MSN Messenger messages
  • Steal login credentials
  • Update Itself
  • Visit a Web Site
It may also prevent the user from using the following applications:
  • cmd.exe
  • ipconfig.exe
  • regedit.exe
  • regsvr32.exe
  • rundll32.exe
  • verclsid.exe
It blocks users from accessing websites with the following strings:
  • avast.
  • avg.
  • avira.
  • bitdefender.
  • bullguard.
  • clamav.
  • comodo.
  • emsisoft.
  • eset.
  • fortinet.
  • f-secure.
  • 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.
It hooks the following API to hide itself and to aid its routines.
  • CopyFileA
  • CopyFileW
  • CreateFileA
  • CreateFileW
  • DeleteFileA
  • DeleteFileW
  • DnsQuery_A
  • DnsQuery_W
  • GetAddrInfoW
  • HttpSendRequestA
  • HttpSendRequestW
  • InternetWriteFile
  • LdrEnumerateLoadedModules
  • LdrGetDllHandle
  • LdrGetProcedureAddress
  • LdrLoadDll
  • MoveFileA
  • MoveFileW
  • NtEnumerateValueKey
  • NtQueryDirectoryFile
  • NtQueryInformationProcess
  • NtQueryInformationThread
  • NtQuerySystemInformation
  • NtQueryVirtualMemory
  • PR_Write
  • RegCreateKeyExA
  • RegCreateKeyExW
  • RtlAnsiStringToUnicodeString
  • URLDownloadToFileA
  • URLDownloadToFileW

It drops shortcut files pointing to the copy of itself in removable drives. These dropped .LNK files use the names of the folders located on the said drives for their file names. It then sets the attributes of the original folders to Hidden to trick the user into clicking the .LNK files.

This description is based on a compiled analysis of several variants of WORM_DORKBOT. Note that specific data such as file names and registry values may vary for each variant.