Mortgage-refinancing spam has jumped to 10 per cent of all junk email in the past week, according to new estimates.
The email security firm warned that further rate changes expected today are likely to spur even more finance-related spam.
Commtouch added that this huge increase in mortgage spam also poses a potential problem with obstructed legitimate emails, known as false positives.
Email correspondence between banks and customers may be delayed or blocked by over-zealous anti-spam technologies which have difficulty differentiating between valid mortgage-related email and finance-related spam.
"Now that market conditions have created fervour among homeowners wishing to refinance their mortgages, cyber-criminals are taking advantage by sending more mortgage-themed spam," said Amir Lev, chief technology officer at Commtouch.
"Loan officers and their customers need to be particularly cautious since some content-based email filtering tools used by banks and consumers may block legitimate email messages and disrupt the communication chain."
Finance-related spam accounted for only two per cent of all spam during the fourth quarter of 2007, according to Commtouch.
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