Spammers Misuse Auto-responder Messages in New Spamming Trick

According to McAfee, an IT security company, spammers are now applying a trick that helps them to elude many anti-spam filters - abusing the "out of the office" and to manipulate the auto-respond utility of authentic Web-based e-mail services. There were many instances that used the trick and the company noticed them in the third week of February 2008.

The security firm explained how with the help of new technique spammers first register with a genuine Webmail account by turning on the auto-respond function and then enter the spam content "Out of the Office" which replaced the automatic message.

He then overwhelms the account by sending e-mails that have spoofed "from" addresses and seem to have arrived from the intended recipients. The default responses are subsequently transmitted to the fake addresses.

According to McAfee, while the technique sounds twisted for distributing spam, it allows the fraudsters to elude spam filters. Meanwhile, the auto-response from a legitimate Webmail service seem real to the spam filtering software.

The security vendor said that one advantage of using the system is that all the spam will arrive from authentic Webmail accounts that are protected with DomainKey Library and Implementing Tools, with Sender ID and DomainKey in place. This means the messages manage to deceive many of the conventional anti-spam shields.

However, experts point out that while auto-responding systems are very good tool, they could be rather inappropriate in certain instances since it answers all Web e-mails. McAfee notes that the auto-responding spam doesn't appear like a standard default reply. The subject line of the message always starts with 'Re:' because it is an addition from the Web-based e-mail service; however, the spammer controls the remaining content of the e-mail.

According to anti-spam engineer Jeremy Gilliat at McAfee, the company in the past weeks has seen a large amount of junk e-mails, apparently from legitimate Webmail services, as reported by vnunet on February 26, 2008.

Meanwhile, McAfee said that spammers are expected to use more of automation techniques in setting up accounts and crafting the responder message, meaning they will have vast numbers of Webmail accounts for their spamming operations, as reported by Techworld on February 26, 2008.

Related article: Spammers Continue their Campaigns Successfully

» SPAMfighter News - 3/4/2008