WORM_DORKBOT.SS

 Analysis by: Sabrina Lei Sioting

 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 instant messaging applications, Propagates via removable drives, Via removable drives

This worm monitors the Internet activities of the infected system to steal user credentials if the user visits websites with certain strings. It attempts to steal user credentials used in the certain websites. It monitors certain browsers. It has backdoor capabilities. It modifies the following system files. It hooks the following API to hide itself and to aid its routines.

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 worm arrives via removable drives. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

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

It prevents users from visiting antivirus-related websites that contain specific strings. It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size:

286,720 bytes

Memory Resident:

Yes

Initial Samples Received Date:

20 Jun 2012

Payload:

Steals information, Compromises system security

Arrival Details

This worm arrives via removable drives.

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

  • %User Profile%\Application Data\{random characters}.exe

(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)

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
  • mIRC

Backdoor Routine

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

  • {BLOCKED}tf404.com
  • {BLOCKED}.com
  • {BLOCKED}6.com
  • {BLOCKED}6.com
  • {BLOCKED}5.com

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.

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=*
  • *.moneybookers.*/*login.pl
  • *1and1.com/xml/config*
  • *4shared.com/login*
  • *:2082/login*
  • *:2083/login*
  • *:2086/login*
  • *:2222/CMD_LOGIN*
  • *alertpay.com/login*
  • *aol.*/*login.psp*
  • *bcointernacional*login*
  • *bebo.*/c/home/ajax_post_lifestream_comment
  • *bebo.*/c/profile/comment_post.json
  • *bebo.*/mail/MailCompose.jsp*
  • *bigstring.*/*index.php*
  • *clave=*
  • *depositfiles.*/*/login*
  • *dotster.com/*login*
  • *dyndns*/account*
  • *enom.com/login*
  • *facebook.*/ajax/*MessageComposerEndpoint.php*
  • *facebook.*/ajax/chat/send.php*
  • *facebook.*/login.php*
  • *fastmail.*/mail/*
  • *fileserv.com/login*
  • *filesonic.com/*login*
  • *FLN-Password=*
  • *freakshare.com/login*
  • *friendster.*/rpc.php
  • *friendster.*/sendmessage.php*
  • *gmx.*/*FormLogin*
  • *godaddy.com/login*
  • *google.*/*ServiceLoginAuth*
  • *hackforums.*/member.php
  • *hotfile.com/login*
  • *letitbit.net*
  • *login.live.*/*post.srf*
  • *login.Pass=*
  • *login.yahoo.*/*login*
  • *login_pass=*
  • *login_password=*
  • *LoginPassword=*
  • *loginUserPassword=*
  • *mediafire.com/*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*
  • *pas=*
  • *pass=*
  • *Passwd=*
  • *Password=*
  • *password]=*
  • *paypal.*/webscr?cmd=_login-submit*
  • *pw=*
  • *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.*/*direct_messages/new*
  • *twitter.*/*status*/update*
  • *twitter.com/sessions
  • *txtpass=*
  • *txtPassword=*
  • *uploaded.to/*login*
  • *uploading.com/*login*
  • *vip-file.com/*/signin-do*
  • *vkontakte.ru/api.php
  • *vkontakte.ru/mail.php
  • *vkontakte.ru/wall.php
  • *webnames.ru/*user_login*
  • *what.cd/login*
  • *whcms*dologin*
  • *youporn.*/login*
  • bebo Comment
  • bebo Lifestream
  • bebo Message
  • clave
  • comment
  • Email
  • EmailName
  • Facebook IM
  • Facebook Message
  • FLN-Password
  • FLN-UserName
  • Friendster Comment
  • Friendster Message
  • Friendster Shoutout
  • login
  • login.Pass
  • login.User
  • login[password]
  • login[username]
  • login_email
  • login_pass
  • login_password
  • loginid
  • loginname
  • LoginPassword
  • LoginUserName
  • loginUserPassword
  • Message
  • msg_text
  • numeroTarjeta
  • Passwd
  • Password
  • quick_password
  • quick_username
  • screenname
  • session[password]
  • session[username_or_email]
  • shoutout
  • status
  • TextfieldEmail
  • TextfieldPassword
  • token
  • Twitter Message
  • Twitter Tweet
  • txtEmail
  • txtpass
  • txtPassword
  • txtuser
  • userid
  • username
  • vkontakte Chat
  • vkontakte Message
  • vkontakte Wall

It attempts to steal user credentials used in the following websites:

  • 1and1
  • 4shared
  • Alertpay
  • Banco International
  • Bebo
  • BigString
  • Brazzers
  • Depositfiles
  • Dotster
  • DynDNS
  • Facebook
  • Fastmail
  • Fileserve
  • Filesonic
  • Freakshare
  • Friendster
  • Gmail
  • Godaddy
  • Hackforums
  • Hotfile
  • IKnowThatGirl
  • Letitbit
  • LogMeIn
  • Mediafire
  • Megaupload
  • Moneybookers
  • Moniker
  • Namecheap
  • Netflix
  • Netload
  • OfficeBanking
  • PayPal
  • Runescape
  • Sendspace
  • Sms4file
  • Speedyshare
  • Steam
  • Thepiratebay
  • Torrentleech
  • Twitter
  • Uploaded
  • Uploading
  • Vip-file
  • Vkontakte
  • Webnames
  • Whatcd
  • Yahoo
  • YouPorn
  • YouTube

It monitors the following browsers:

  • Flock
  • Google Chrome
  • Internet Explorer
  • Mozilla Firefox
  • Opera

It has the following backdoor capabilities:

  • Join an IRC channel
  • Update Itself
  • Download other files
  • Perfrom Slowloris, UDP, and SYN flooding
  • Run Reverse Socks4 proxy server
  • Send MSN Messenger messages
  • Insert iframe tags into HTML files
  • Visit a Web Site
  • Block DNS
  • Steal login credentials
  • Log in to FTP sites
  • Create processes
  • Modify the following system files:

    ipconfig.exe
    verclsid.exe
    regedit.exe
    rundll32.exe
    cmd.exe
    regsvr32.exe
Other Details

It hooks the following APIs to hide itself and to aid its routines:

  • CopyFileA
  • CopyFileW
  • CreateFileA
  • DeleteFileA
  • DeleteFileW
  • DnsFree
  • DnsQuery_A
  • DnsQuery_W
  • GetAddrInfoW
  • HttpSendRequestA
  • HttpSendRequestW
  • InternetWriteFile
  • MoveFileA
  • MoveFileW
  • NtEnumerateValueKey
  • NtQueryDirectoryFile
  • PR_Write
  • RegCreateKeyExA
  • RegCreateKeyExW
  • 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.

  SOLUTION

Minimum Scan Engine:

9.200

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.SS

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

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.
  • {drive letter}:\RECYCLER

Step 6

  1. Open a command prompt.
    • For Windows 2000, Windows XP, and Windows Server 2003 users, click Start>Run. In the Open input box, type CMD then press Enter.
  2. In the CMD console, type the following:

    ATTRIB [+R | -R] [+A | -A ] [+S | -S] [+H | -H] [+I | -I] [drive:][path][file name] [/S [/D] [/L]]

    Where:
    + Sets an attribute.
    - Clears an attribute
    R Read-only file attribute
    A Archive file attribute
    S System file attribute
    H Hidden file attribute
    I Not content indexed file attribute
    [drive:][path][filename]
    Specifies a file or files for attrib to process
    /S Processes matching files in the current folder and all subfolders.
    /D Processes folders
    /L Work on the attributes of the Symbolic Link versus the target of the Symbolic Link
    Example:
    To unhide all files and folders (including subfolders) in drive D:
    ATTRIB –H D:\* /S /D
  3. Repeat Step 2 for folders and files in other drives or directories.

Step 7

Search and delete this file

[ 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.
  • {drive letter}:\{folder name}.lnk

Step 8

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

[ Learn More ]


[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

Step 9

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


Did this description help? Tell us how we did.