Business email is increasingly being overtaken by spam, with just one legitimate email out of every 28 which are hitting corporate inboxes, according to Sophos.
According to Sophos' latest report, last month the amount of spam as a percentage of all email was actually higher than any point in 2008, at 96.5 per cent compared to 92.3 per cent in the first three months of this year.
The report also saw that spammers were increasingly using social networking websites such as Facebook and LinkedIn to push fake spam links.
Sophos senior technology consultant Graham Cluley said that this was because spammers were being increasingly thwarted by anti-spam defences at the corporate email gateway.
He said: "To get around this, we are seeing spammers exploiting networks like Facebook to plant spam messages on other peoples' profiles. These don't just get read by the owner of the profile, but anyone else visiting his or her page."
The growing trend for spammers to use social networks was also seen with spear phishing', which is when messages are personalised and appear to come from a trusted source.
For example, an IT staff member at the same company might ask for personal information or log-in details. Spear-phishers manage to get those details by either using special software or lists of employees which can be found on many social networking sites.
Even though spam has become a regular occurrence, users were warned not to let their guard down. Cluley said: "It should be remembered that some spam is not just a nuisance, but malicious in its intent - trying to get you to click on an attached Trojan horse or lead you to a dangerous website."
