Spammers have launched a new attack that could jeopardise the security of SMEs, new figures show.The latest report by MessageLabs reveals an increase in spam spikes, which occur when individual domains are targeted in a particularly aggressive spam attack. Analysts detected a spike last month, in which more than 10,000 spam messages were attempted and accounted for more than 75 per cent of the total emails received by the domain during the entire period.
According to MessageLabs, this form of attack is particularly dangerous to small- and medium-sized businesses. The surge causes an overload of email servers and evades appliance-based anti-spam technology that relies heavily on signatures created over a long period of time.
“This month the bad guys continued with their aggressive attacks by developing new methods to fly under the radar and cause the most damage,” said Mark Sunner, chief security analyst at MessageLabs. “With the increase in spam spikes it is crucial for businesses to take a multi-layered security approach among email, Web and IM to protect their employees and their systems completely from these malicious attacks.”
The report also found that spammers are switching tactics to dodge traditional anti-spam systems. Instead of embedding images in the body of the email, the attackers are now hosting images on sites that don’t require registration and feature links to those websites or an HTML image in the message. Experts believe the group using this method is the same unit responsible for the recent abuse of Imageshack and until registration requirements are enforced these scams will continue.