In response to a newly announced vulnerability in Microsoft's Internet Explorer web browser, there is need for heightened security awareness when accessing the web.
Read about it on the Microsoft website: http://technet.microsoft.com/en-us/security/advisory/2757760
The vulnerability appears to affect Internet Explorer 6, 7, 8 and 9 on Windows XP, Vista and 7. Internet Explorer 10 is not reported to be affected. Microsoft is working on a fix for the vulnerability.
Actual exploits currently exist that may execute code on your system (with the privilege level of the current user) simply by browsing to a malicious website. It would be preferable to use an alternate browser (Chrome, Firefox, Safari, etc.) until a patch has been deployed and installed on your system.
Note that if you use Internet Explorer to access internal McGill systems, such as Banner, Minerva, etc. this will not pose a risk.
Furthermore, take extra caution while clicking on any unfamiliar links in your email. Always hover over links and try to ensure the links are navigating you to your intended destination.