Spam email dropped to its lowest level (113 billion) in more than three years during the second quarter of 2011, a sign that spammers are shifting gears in the way they attack unsuspecting electronic mailboxes, a new report shows. Nonetheless, spam still accounted for 75 percent of all email.
Spammers today favor compromised accounts (known as zombies in security parlance) for sending spam, gradually shifting distribution away from botnets, which are networks of compromised computers used for mass mailings of spam, Commtouch, a cloud-based Internet security firm, found in its quarterly report on Internet threat trends.
The shift in tactics is likely the result of several high-level botnet takedowns by law enforcement agencies, Commtouch said.
"Spammers are trying to out-maneuver IP-based spam blocking techniques as well as law enforcement that have both effectively targeted botnets," said Amir Lev, Commtouch's chief technology officer. "They are now using a combination of malware and phishing to compromise legitimate accounts and then using these accounts to send low-volume spam outbreaks."
To help pump of their spam volume, tricksters upped up their efforts to compromise individual computer accounts. Approximately 377,000 zombie computers were activated daily during the second quarter, a significant increase compared to the 258,000 zombies activated in the first three months of the year.
India keeps its title as the country with the most zombie computers—it houses 17 percent of all zombies worldwide.
The most popular spam topic during this period was pharmacy ads, Commtouch said, although these ads now represent only 24 percent of all spam, down from 28 percent in the first quarter.
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