互联网解决方案提供商思科在其《年度安全报告》中称，由于黑客不断想出控制用户计算机的新途径，被控制的计算机每天会发送大量垃圾邮件，这些垃圾邮件数量达到近2000万封，占全部电子邮件总量的约90%。该报告指出，美国是最大的垃圾邮件“源头”，占到了垃圾邮件总量的17.2%；土耳其和俄罗斯分列第二、三位，所占比例分别为9.2%和8%。

Junk e-mail, or spam, accounts for nearly 200 billion messages daily, approximately 90 percent of email worldwide, according to the Cisco Annual Security Report.

Armies of hijacked¹ computers are flooding the world with spam as hackers² devise slicker ways to take over unwitting people's machines, according to a report released on Monday.

Virus-infected computers are woven into "botnets" used to attack more machines and to send sales pitches to e-mail addresses in low-cost quests to bilk readers out of cash.

"Every year we see threats evolve as criminals discover new ways to exploit people, networks and the Internet," said Cisco chief security researcher Patrick Peterson, who was involved in drafting the report.

Junk e-mail, or spam, accounts for nearly 200 billion messages daily, approximately 90 percent of email worldwide, according to the Cisco Annual Security Report.

The US is the biggest source of spam, accounting³ for 17.2 percent messages. Turkey and Russia ranked second and third, accounting for 9.2 percent and 8 percent spam respectively, according to Cisco.

This year, botnets were used to inject an array of legitimate⁴ websites with an IFrames malicious⁵ code that reroutes visitors to websites that download computer viruses into their machines.

"The botnet is, in many cases, ground-zero for online criminal threats," Peterson said. "Using malware to infect someone's computers is an incredibly common mechanism⁶ and harnessing them all together is a way they do their click fraud, spam emails, and data stealing."

Online criminals are turning botnets on web-based e-mail accounts. Hackers are "reputation hijacking⁷" by using botnets to figure out weak passwords protecting web-based e-mail accounts, according to Peterson.

Weak passwords consist of family names, birthdays, home addresses or other terms considered relatively⁸ easy to deduce.

Once access is gained to legitimate e-mail accounts, a plethora⁹ of spam messages are sent in the owners' names.

Vocabulary:

botnet: 僵尸网络，是许多台被恶意代码感染、控制的与互联网相连接的计算机。一般被计算机犯罪分子用来发送垃圾邮件、传播计算机病毒、发动拒绝服务攻击。

malicious code: 恶意代码

ground-zero: 攻击目标