The number of junk email messages clogging inboxes could be set to soar with spammers harnessing a new technique to churn out advertising missives.
Steve Linford, head of the UK anti-spam organisation Spamhaus, says spammers are now using a clever trick to get around current spam-blocking defences. Instead of sending spam using illegitimate mail servers, he says they are now routing messages through valid servers via hijacked home computers.
Much spam already comes from personal computers. These are typically infected by a computer virus or worm and converted into miniature email servers without a user鈥檚 knowledge. Spammers can route messages through these machines at will.
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Anti-spam 鈥渂lacklists鈥� have proven increasingly effective at blocking unwanted email from these computers. But the latest version of software used to remotely send spam from hijacked computers could undermine the effectiveness of spam blacklisting as it affects the whole mail server.
After taking over a computer, these programs send a network query to its internet service provider (ISP) to find the address of the host鈥檚 mail server. It uses this address to forward junk emails. 鈥淭his is going to increase spam even more,鈥� Linford told 快猫短视频.
Blocking systems
The trick means that spam cannot be blocked without restricting all email sent from an affected ISP. 鈥淚t鈥檚 cunning because to blacklist ISPs would be a nightmare,鈥� says Mark Sunner, chief technology officer at UK email filtering company MessageLabs.
Linford says ISPs can take several steps to counter the problem. Firstly, they can restrict the amount of email any single user can send. They can also use separate servers to send and collect email, which should make it more difficult for spammers to identify the one used to send emails.
Finally, Linford says ISPs can use a secure email sending technology called 鈥淪MTP AUTH鈥�. This requires each message to be accompanied by a username and password before it can be sent.
But Sunner believes this would prove costly and time-consuming for the companies involved. 鈥淚SPs are going to have to take a look at the structure of their mail systems but that could be a lot of work,鈥� he told 快猫短视频.
He adds that spammers will inevitably find a way around new countermeasures, given time. 鈥淚t鈥檚 very much a moving target,鈥� he says. 鈥淲hat we鈥檙e seeing is an arms race between spammers and anti-spammers.鈥�
