A zombie is a computer that has been compromised by attackers, typically for the purpose of sending spam e-mail and viruses to literally millions of recipients. Once installed on the victim’s computer, the Trojan allows a remote hacker to take control of the machine and use it for any of a number of nefarious purposes.
In fact, today’s hackers (the “zombie masters”) have become so sophisticated that they have begun creating coordinated networks of zombie computers that can launch a full-scale attack at a moment’s notice. This traffic can include: Spam, Phishing scams, Viruses, Distributed Denial of Service attacks, Redirects to websites containing malicious code.
Zombies can be created in several ways, including via peer-to-peer networks and maliciously encoded websites. However, the most popular method for distributing the Trojans that create zombies is via an e-mail attachment masquerading as an innocent file, such as a digital photo or contest entry form.
The first generation of zombies was made up mostly of corporate-based machines such as Web, e-mail, or DNS servers. Because these machines were on high-speed networks, they provided an ideal platform from which damaging attacks could be launched. Because these machines were on high-speed networks, they provided an ideal platform from which damaging attacks could be launched.
However, corporate systems have become increasingly secure and more tightly monitored, making them less attractive to hackers. Now, the hackers have turned to the next set of victims, vulnerable home computer users. These computers are easy targets, as home users often lack the Internet savvy necessary to adequately protect their machines with firewalls and up-to-date anti-virus protection; many will also willingly open email attachments from unknown senders, enticed by the promise of easy money or cheap prescriptions.
In addition, the widespread availability of always-on, high-speed home connections using cable and DSL has made the home user an obvious target for zombie masters. In fact, this alone is the single largest contributing factor to recent escalations in spam, phishing attacks and Distributed Denial of Service (DDoS) attacks.
When the attacks involve distribution of viruses via spam techniques, the stakes are raised even higher. The costs of a DDoS attack can be crippling to today’s enterprise, resulting in lost sales during downtime and recovery, and more importantly, loss of trust from partners and customers should the attack become public information.
Taking into consideration that each zombie involved in a recent DDoS attack launched 64 connection attempts per second against the targeted corporation, it’s easy to see how even the most robust systems can wilt under the massive load inflicted upon them.
Some basic tenets of security should be followed at all times, whether you want to protect your enterprise network from spam, viruses and DDoS attacks spewed forth by zombie networks, or protect your home computer from joining the ranks of the undead. The best-of-breed appliances available offer both inbound and outbound protection via an objective, dynamic reputation system, connection management technology and robust anti-virus capabilities.
The best-of-breed appliances available offer both inbound and outbound protection via an objective, dynamic reputation system, connection management technology and robust anti-virus capabilities.
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