An internet security company has warned that next Monday could be the worst day of the year for computer attacks.
The spread of viruses and malicious software is expected to peak on Nov 24, along with attempts by hackers to seize control of computers, according to PC Tools.
The company has analysed information on more than 500,000 computers worldwide, and looked at data from the same period last year, which appears to suggest the Monday before Thanksgiving in the US is a prime time for security attacks.
PC Tools believes this could be because of the increased online activity at this time of the year, as people starting shopping online for Christmas gifts, and for details of bargains they might be able to pick up on Black Friday, the day after Thanksgiving, when many US stores hold huge sales.
Online shoppers are a tempting target for hackers and fraudsters, many of whom will try and trick consumers into clicking links in emails and websites that will download software onto their computers that allows malicious attackers to take remote control of the system.
Hackers will then be able to log keystrokes in order to access banking login details and passwords for online shopping sites.
Security experts have warned web users to be especially vigilant in the run-up to Christmas.
People who plan to do their gift shopping on the internet should ensure their anti-virus software and firewall security is up to date, that they don't open emails and files from unfamiliar people, and that they ensure they only enter credit or debit card information on secure web pages.
This is denoted by the appearance of a padlock symbol somewhere around the border of the webpage or in the address bar, and the "http://" prefix for the website changing to "https://" to show it is a secure link.