So far this year, Symantec says it had not observed malware levels above 3% of all spam, even on days when malware spam spiked.
However, the firm says its July 'State of Spam and Phishing' report shows that malware spam made up almost 12% of all spam on June 13, and topped 5% on June 3 and 15.
According to Symantec, the overall phishing numbers increased approximately 25% this month. The increase was attributed to nearly all sectors of phishing.
Phishing websites created by automated tool-kits doubled with an increase of 123% from May, whilst unique URLs increased by 12% from the previous month.
Interestingly, the report notes that phishing websites with IP domains – e.g. domains like http://255.255.255.255 – were the only sector to have decreased by about 2% from May.
Delving into the report shows that web hosting services comprised 11% of all phishing, an increase of 26% from the previous month.
The number of non-English phishing sites, meanwhile, increased by 15%, whilst among the non-English phishing sites, French and Italian addresses continued to be higher in June.
Phishing in French increased by 25% - mainly in the e-commerce sector.
In its conclusions, the report recommends that users should not open unknown email attachments, as then could infect your computer.
Users are also being advised not to reply to spam, as, whilst the sender's email address is usually forged, replying may only result in more spam.
Internet users should never fill out forms in messages that ask for personal or financial information or passwords.
A reputable company, says Symantec, is unlikely to ask for your personal details via email.
"When in doubt, contact the company in question via an independent, trusted mechanism, such as a verified telephone number, or a known Internet address that you type into a new browser window", says the report.