US-CERT is aware of public reports of malicious code circulating via spam email messages related to the IRS. The attacks arrive via an unsolicited email message and may contain a subject line of "Notice of Underreported  Income." These messages may contain a link or attachment. If users click on this link or open the attachment, they may be infected with malicious code, including the Zeus Trojan.

US-CERT encourages users and administrators to take the following measures to protect themselves:

• Review the How to Report and Identify Phishing, E-mail Scams and Bogus IRS Web Sites document on the IRS website.
• Do not follow unsolicited web links or attachments in email messages.
• Maintain up-to-date antivirus software.
• Refer to the Recognizing and Avoiding Email Scams (pdf) document for more information on avoiding email scams.
• Refer to the Avoiding Social Engineering and Phishing Attacks document for more information on social engineering attacks.
  

Read more at: US-CERT Current Activity