SAN FRANCISCO: Some hackers are exploiting Microsoft’s offer of free upgrades to its new Windows 10 operating system. Security researchers are warning about a wave of bogus spam e-mails with malicious attachments, labelled as if they’re legitimate copies of the new programme. The attachments contain a ‘ransomware’ programme that, when opened, locks all the data on a computer and demands payment to release them. Researchers at Cisco Systems say the e-mails are designed to look like an official upgrade notice from Microsoft Corp, but several words have random, out-of-place letters and punctuation. Another important clue: Microsoft says its update mechanism provides computer owners with a notice on their screens — not via e-mail — when a direct internet download is available. Experts warn against clicking on files that come with unsolicited e-mails.

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