Skip to main content

Net-Worm:W32/Koobface.CY

Classification

Category:

Malware

Type:

Net-worm

Aliases:

  • Net-Worm:W32/Koobface.CY
  • TR/Dldr.Agent.atbf.1 (Avira)
  • W32/Koobfa-Gen (Sophos)
  • Worm:Win32/Koobface.gen!A (Microsoft)
  • W32/Koobface.worm (McAfee)
  • W32.Koobface.B (Symantec)

Summary

This malware is installed via a fake YouTube webpage (where it is posing as a Flash player update) displayed by Net-Worm:W32/Koobface.CZ.The purpose of this malware is to post comments with HTML links in various online networking locations in order to spread itself.

Removal

Technical Details

The following sites are referenced in the body of Koobface.CY:

  • bebo.com
  • blackplanet.com
  • facebook.com
  • friendster.com
  • myspace.com
  • myyearbook.com

The routines in Koobface.CY directly target Facebook and the other sites are not used by this variant.

Execution

Upon execution, the malware will create these files:

  • %windir%\bolivar28.exe- Copy of the malware
  • %windir%\fmark2.dat- Malware's data file
  • c:\1.reg- Contains a routine to add entries to the registry
  • c:\64234543.bat- Cleanup routine

It will also display this fake error message:

The malware will then add this entry to the registry so that it will be able to insert an HTML page into another HTML page; this ability can be used to insert comments in user pages inside networking sites.

  • HKEY_CLASSES_ROOT\Mime\Database\Content Type\application/xhtml+xml"CLSID"="{25336920-03F9-11cf-8FD0-00AA00686F13}""Extension"=".xml""Encoding"=hex:08,00,00,00

Propagation

Once installed, Koobface.CY will send an HTTP POST message to this location in order to retrieve the information that it will use as comments:

  • https://y171108.com/[...]/first.php

The site also contains the malware download location. The information and download location are combined to form the messages the worm will post to all of the infected user's contacts on the social interaction site.In addition, Koobface.CY contains a routine to connect to these locations:

  • https://y171108.com/[...]/logs.php
  • https://y171108.com/[...]/gen.php

The gen.php location also contains information that can be posted as comments on different websites.

Packer

Koobface.CY is packed with UPX.

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.