Spam barrages take down filters, networks

Report shows increase in spam bombardment attacks.

MessageLabs' monthly report on the latest trends in spam has warned of an alarming rise in 'spam spikes', targeted attacks which use high volumes of spam directed at a single company in an attempt to overwhelm gateway spam filters.

The aim of the attack is to cause overloaded anti-spam software running on gateway servers or appliances to shut down and thus allow spam messages to penetrate to end users, but the spikes often cause total denial of service in a similar manner to a traditional DDoS attack. An example spike shows 10,000 spam mails hitting one organisation in an 11-hour period, accounting for over 75% of all mails received in that time.

Among other significant trends last month is a rise in spams with links to images hosted on external sites, rather than embedded in the mail itself. A summary of the findings is here, with the full report available to download from here.

07 June 2007

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