Skip to main content

Net-Worm:W32/Koobface.ES

Classification

Category:

Malware

Type:

Net-worm

Aliases:

  • Net-Worm:W32/Koobface.ES
  • Net-Worm.Win32.Koobface.es
  • Worm:Win32/Koobface.I (Microsoft)
  • W32/Koobface.worm (McAfee)
  • W32.Koobface.A (Symantec)

Summary

Koobface.ES replicates by sending messages to the friends listed in an infected user's account with a social networking website. The malicious message includes a link to a webpage/website where unsuspecting visitors can be infected in turn. Major social networking websites are targeted by this worm, including Facebook, MySpace, Friendster and Livejournal.

Removal

Technical Details

Activity

On its first execution, the worm installs itself by copying itself to the Windows directory. During the execution, a message box is displayed, which appears as:

Next, the worm looks for and connects to a remote active domain server and starts looking for cookies related to major social networking websites (see the list below). If any relevant cookies are found, the worm will hijack the user's account on the social networking site, in order to go through the respective site and search for the user's friends/contacts.Once information related to the user's friends has been compiled, the worm sends this information to a server, where the data is used to create a message. The message is then sent to the user's friends.The generated message contains a link to a webpage where a copy of the worm can be downloaded. For example, the webpage may be a Fake YouTube page, which comes complete with fake comments. The user name and picture is pulled from the social networking site. Clicking anywhere on the page will download a copy of the worm. Most social networking websites will use Completely Automated Public Turing Test To Tell Computers and Humans Apart (CAPTCHA) to ensure that actual people, rather than computer programs, are creating user accounts. To circumvent the CAPTCHA security, the worm sends the CAPTCHA image back to its servers to be resolved. The answer is then sent back.

Installation

During installation, the worm creates a copy of itself in the Windows directory, using the file name freddy35.exe. It also drops a batch file, whose purpose is to delete the worm's own files after its first execution.The worm also makes a number of registry changes. One of the changes made displays MIME (type xhtml+xml without prompt).The worm needs to communicate with a server to function. A few possible server domains the worm can connect to are:

  • 1dns210109 .com
  • temp210108 .com
  • wm21012009 .com
  • open21012009 .com
  • er21012009 .com

The server is where the following functions are carried out:

  • Search for cookies to social networking sites
  • Resolves CAPTCHA images
  • Generates messages
  • Send further commands to the worm

During its communication with the server, the worm searches for cookies of these sites:

  • Facebook
  • Hi5
  • Friendster
  • Myyearbook
  • Myspace
  • Bebo
  • Tagged
  • Netlog
  • Fubar
  • Livejournal

The server can send the following commands:

  • START
  • RESET
  • SIMPLEMODE
  • DOMAIN_B
  • DOMAIN_C
  • DOMAIN_M
  • EXIT
  • FBSHAREURL
  • FBTARGETPERPOST
  • INVITE
  • LINK_B
  • LINK_C
  • LINK_M
  • TEXT_B
  • TEXT_C
  • TEXT_M
  • TITLE_B
  • TITLE_M
  • UPDATE
  • RAZLOG
  • RCAPTCHA
  • SHARELINK
  • BASEDOMAIN
  • STARTONCE
  • WAIT
  • POST

File System Changes

Creates these files:

  • %windir%\freddy35.exe

Registry Modifications

Creates these keys:

  • HKLM\Software\Microsoft\Windows\CurrentVersion\Run Sysftray2 = %windir%\freddy35.exe
  • HKEY_CLASSES_ROOT\MIME\Database\Content Type\application/xhtml+xml CLSID "{25336920-03F9-11cf-8FD0-00AA00686F13}" Extension ".xml" Encoding hex:08,00,00,00,
  • HKEY_LOCAL_MACHINE\SOFTWARE\Classes\MIME\Database\Content Type\application/xhtml+xml CLSID "{25336920-03F9-11cf-8FD0-00AA00686F13}" Extension ".xml" Encoding hex:08,00,00,00,

Protect your devices from malware with F‑Secure Total

Protecting your devices from malicious software is essential for maintaining online security. F‑Secure Total makes this easy, helping you to secure your devices in a brilliantly simple way.

  • Award‑winning antivirus and malware protection

  • Online browsing, banking, and shopping protection

  • 24/7 online identity and data breach monitoring

  • Unlimited VPN service to safe­guard your privacy

  • Password manager with private data protection

Choose how many devices you want to protect to get started.

  • Free customer support

  • Cancel anytime

  • The trial does not obligate you to buy the product

After 30 days your subscription will renew automatically for one year at €69.99.

More Support

Community

Ask questions in our Community.

User guides

Check the user guide for instructions.

Contact Support

Chat with with or call an agent.

Submit a Sample

Submit a file or URL for analysis.