We simulated simple message-dropping attacks in which attackers drop all messages, as well as coordinated, distributed message-dropping attacks in which attackers vary their behavior to avoid detection.
But those were all "distributed denial of service" attacks in which attackers flood the sites with traffic until they fall offline.
Other cyberweapons include distributed denial-of-service, or DDoS, attacks, in which attackers, using malware, hijack a large number of computers to create so-called botnets, groups of "zombie" computers that then attack other targeted computers, preventing their proper function.
At the International Symposium on Computer Architecture in June in San Diego, Zhenghong Wang, one of Lee's graduate students, presented a paper describing a hardware approach to preventing so-called "software side-channel attacks" during which attackers exploit the cache memories that are shared between computer programs to leak secret cryptographic keys.
The software's Internet-connection features, he contends, makes server computers more susceptible to a Web intrusion known as a distributed denial of service attack, in which attackers remotely commandeer hundreds of personal computers connected to the Internet and use them to release a disabling deluge of data against a Web site.
The new features, he says, makes server computers more susceptible to a type of Web intrusion known as a distributed denial of service attack, in which attackers remotely commandeer hundreds of personal computers connected to the Internet and use them to release a disabling deluge of data against a specific Web site.
"This is consistent with a DDoS attack on their routers," he said, referring to a distributed denial of service attack, in which attackers flood a network with traffic until it collapses under the load.If the attack was American in origin — something the United States would probably never acknowledge — it would be a rare attack on another nation's Internet connections.
That might have exposed Lenovo users to so-called "coffee shop attacks", in which attackers hijack a connection to a public wi-fi network.
In addition, two of three of those suicide attacks are considered "complex," in which attackers use a suicide bomb as well as other weapons.
The company suffered a massive attack against their systems in which attackers made off with as many as 100 million debit and credit cards in 2008.
In some cases, cryptography has been leveraged by attackers, most notably in ransomware attacks against healthcare providers during which attackers encrypt critical data and demand a ransom in return.
