In the past day or so there has been a virus released on Yahoo Groups that spread via a Javascript exploit in Yahoo's server code. This expoit allows the virus to infect a computer simply by a person opening a post. The virus has been spreading itself in Yahoo Groups posts titled "New Graphic Site". DO NOT open these posts, as they have virus javascript embedded in them. For more information, check out Symantec's article on the virus:

http://securityresponse.symantec.com/avcen...yamanner@m.html

QUOTE
JS.Yamanner@m is a worm that is written in JavaScript. It exploits a vulnerability in the Yahoo email service to send a copy of itself to the user's Yahoo email contacts.

Notes:

    * The worm cannot run on the newest version of Yahoo Mail Beta.
    * Rapid Release Definitions with sequence number of 55078 or greater are required to detect this threat.

Also Known As:  JS/Yamanner@MM [McAfee], JS_YAMANER.A [Trend Micro]

Type:  Worm
Infection Length:  6,377 bytes.

Systems Affected:  Windows 2000, Windows 95, Windows 98, Windows Me, Windows NT, Windows Server 2003, Windows XP

June 12, 2006

threat assessment

Wild

    * Number of infections: 0 - 49
    * Number of sites: 0 - 2
    * Geographical distribution: Low
    * Threat containment: Easy
    * Removal: Easy

Damage

    * Payload Trigger: n/a
    * Payload: n/a
          o Large scale e-mailing: Sends a copy of itself to the user's Yahoo email contacts.
          o Deletes files: n/a
          o Modifies files: n/a
          o Degrades performance: n/a
          o Causes system instability: n/a
          o Releases confidential info: n/a
          o Compromises security settings: n/a

Distribution

    * Subject of email: New Graphic Site
    * Name of attachment: n/a
    * Size of attachment: n/a
    * Time stamp of attachment: n/a
    * Ports: n/a
    * Shared drives: n/a
    * Target of infection: n/a

technical details

JS.Yamanner@m performs the following actions:

  1. Arrives on the compromised computer as an HTML email containing Javascript. The email may have the following characteristics:

      From: Varies
      Subject: New Graphic Site
      Message body: Note: forwarded message attached.

  2. Once the email is opened the worm exploits a vulnerability in the Yahoo email service to run a script.

  3. Sends a copy of itself to certain email addresses gathered from the Yahoo email folders.

  4. Targets email addresses from the @yahoo.com and @yahoogroups.com domains.

  5. Contacts the following URL:

      [http://]www.av3.net/index.htm

  6. Sends a list of email addresses gathered to the above URL.