Sophos researchers are warning of e-mails that appear to come from the IRS, stating that a tax refund appeal has been denied.

"Here's a typical message: 'Dear Business owner, Hereby you are notified that your Income Tax Refund Appeal id#6636527 has been DECLINED. If you believe the IRS did not properly estimate your case due to a misunderstanding of the facts, be prepared to provide additional information. You can obtain the rejection details and re-submit your appeal by using the instructions in the attachment,'" writes Sophos' Graham Cluley.

"Of course, the attached HTML file is malicious and you should not open it," Cluley writes. "Sophos detects it as Mal/Iframe-AE."

Go to "Malware attack claims the IRS has rejected your tax appeal" to read the details.

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