An e-mail scam has hit tens of thousands of users at dozens of colleges over the past few weeks, leaving network administrators scrambling to respond before campus computer accounts are taken over by spammers. Students, professors, and staff members at the affected colleges received e-mail messages that purported to come from the colleges' help desks, asking users to reply with their log-in and password, and in some cases other personal information including birth date. But the messages actually come from hackers who use the information to send spam messages from the accounts. Administrators worry that the compromised accounts could be used to do further damage to the university networks. At least 86 colleges and universities have been hit by the scam messages, says Douglas Pearson, technical director of the Research and Education Networking Information Sharing and Analysis Center at Indiana University at Bloomington. He took an informal survey of college-security administrators last week via an e-mail list. The type of attack is known as phishing. In the past, most phishing e-mail messages pretended to come from banks, from eBay, or from the online-payment service PayPal. Some college officials say that this year is the first time they have seen phishing schemes that pretend to be sent from college IT departments.