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How Hackers Take Down Web Sites [Video]


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Courtesy of Scientific American

Many of the Web sites we visit every day are under cyber attack by malicious hackers looking to disrupt business transactions, discourage people from using a particular online service or exact payback for some real or perceived slight. One of the most common ways to bring down a site is to flood its computer servers with so much traffic, they slow to a crawl or shut down because they simply can’t handle the volume. This is known as a denial-of-service (DOS) attack.

The weapon of choice in these cyber salvos is the botnet, a virtual armada of computers consigned to deluge Internet servers with requests for data to the extent that those servers cannot function. Botnets are used to perpetrate distributed DOS (DDOS) attacks against a target, and often the owners of those computers don’t even know that their systems are up to no good. This is because cyber criminals first break into those computers using a virus, worm or some other malware, turning someone’s PC or server into a “zombie” that can be controlled remotely.

Scientific American’s Instant Egghead video below offers additional info on how these attacks work.

In one high-profile example, the hacker group Anonymous launched a DDOS against Paypal, MasterCard, Visa and others in December 2010—dubbed Operation Payback—after the payment services stopped processing donations to the WikiLeaks site. Operation Payback participants used a piece of software called the Low Orbit Ion Cannon (LOIC) to recruit computers for their attacks. LOIC actually included a feature that allowed computer users to voluntarily join Anonymous botnets. U.S. authorities charged 14 people for their roles in the attacks.

One of the newer approaches to launching DDOS attacks is to recruit mobile devices via DDOS apps to participate in these attacks, according to a recent report from cyber security firm Prolexic Technologies. In such cases, mobile device owners actually agree to participate in the attack by downloading the app and giving control of their phone or tablet to the attacker. This may not have been a real threat a few years ago, but the proliferation of increasingly powerful mobile devices has made them a valuable contributor to any botnet, the report says.

Attackers often protect their own identities by creating forged Internet protocol (IP) sender addresses for the servers they commandeer to commit DDOS attacks. Any investigation into the source of the assault leads to a spoofed address rather than the actual perpetrator. An increasingly popular approach is for an attacker to send forged requests for information to a computer or group of computers, which in turn send their flood of responses to that forged address. This is known as a distributed reflected DOS attack because the actual culprit is using an unwitting middleman to perform an attack. Taking this one step further, sometimes attackers deliberately create queries that elicit much larger responses, thus amplifying the attack without much additional effort.

Site owners can combat DOS attacks in a number of ways—adding more servers for redundancy and backup or setting up firewalls that attempt to filter traffic coming from questionable sources, for example. Unfortunately attackers continue to find ways around such defenses, creating an escalating virtual arms race involving Web sites, cyber criminals and law enforcement.

About the Author: Larry is the associate editor of technology for Scientific American, covering a variety of tech-related topics, including biotech, computers, military tech, nanotech and robots. Follow on Twitter @lggreenemeier.

The views expressed are those of the author and are not necessarily those of Scientific American.





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  1. 1. sarsabziran 10:36 pm 02/11/2014

    http://www.scientificamerican.com/article/why-is-the-earths-core-so/

    Dear Editor,

    Recently, I have been collecting some information to complete an article on the mechanisms of drought in the Iranian Plateau. Due to the peculiar geologic character of the land in that part of the world, I had to search for mechanisms by which the plate tectonics move, which led me to the question of internal heat and “WHAT KEEPS THE CORE OF OUR PLANET SO HOT!? Searching for the plausible answers to the above question, has been disappointing at best if not outright misleading. With this backdrop, I try to raise questions about the current and prevailing mindset and perhaps provide some explanation to the question: WHAT IS THE SOURCE/MECHANISM (S) OF EARTH’S INTERNAL HEAT?
    In searching for an answer, I found that Earth’s core is hot because of three mechanisms: (1) heat from when the planet formed and accreted, which has not yet been lost; (2) frictional heating, caused by denser core material sinking to the center of the planet; and (3) heat from the decay of radioactive elements.
    While some 4.6 billion years have passed since its accretion, the third planet has kept a core temperature of above 6,000˚ C. Although the crust, the mantle and the atmosphere ostensibly provide, an insulating blanket – albeit very inefficient- around the planet, it is implausible that our planet could have saved a significant portion of its initial accretion thermal energy. The warming and cooling of Earth’s surface temperature in presence (day time) and absence (night time) of the Sun’s energy is indisputable evidence for lack of any significant insulating mechanism. The almost immediate cooling of exuded lava on the surface is further evidence that Earth lacks any such insulating mechanisms, and that it would have cooled down precipitously, unless the planet has had an internal heat generating process. In fact, based on the mathematical calculations of Kelvin the initial heat of accretion/ collision should have dissipated in no longer than 20-40 million years, but most likely much earlier, since planet’s inception.
    With regard to radioactive decay playing a significant role in generation of Earth’s internal heat, it is hard to accept it for the following reasons: 1) radioactive elements make up a small fraction of earth’s total mass. If radioactive hydrogen is taken as an example, it is clearly implausible that deuterium or tritium in such low concentrations in the ocean waters has any significant role in raising the water temperature; 2) many of the common radioactive elements have a short half-life and they should have decayed long ago to be effective sources of heat inside Earth today; and 3) even 40-K with a half-life of 1.2 x 109 years would have been reduced to less than 15% of the original amount in 4.6 billion years! And of course, the Earth’s core temperature should have been inevitably and proportionately reduced, but evidence does not show such trends. We know that Earth’s core is as hot as the Sun’s surface, or its initial temperature! The third mechanism proposed, i.e. frictional heating is also implausible. The somewhat cooled-down molten materials ear the surface that have the same density as the core are as heavy as the molten materials in outer core and peripheral magma, thus making the inward motion very slow. This slow sinking is hard to generate such tremendous amounts of heat to elevate the core temperature to 6000˚ C! In fact the vertical movement may be an effect rather than cause.
    Therefore, it can be concluded that none of the three proposed mechanisms above is individually or in combination, responsible for a significant portion of thermo-generation inside planet Earth.

    Here are some thoughts that crossed my mind. I would like to pose them to the scientific community for verification.

    1. The Earth’s core heat may come in part (not a significant portion) from radioactive decay however, radioactive elements ought to be continually produced in a fusion-like process which may be possible under the intense internal heat of the planet’s core, i.e. by creating a plasma-like amalgamate of subatomic particles down there. Regardless of the mechanisms of production, a continual production of these radioactive elements would be necessary to fuel and maintain the fission-based heat-generating processes inside the Earth.

    2. The Earth’s inner core is under intense pressure from outer layers, to the extent that it turns from liquid to solid. This change of state is a thermo-genic process. The same way that when water solidifies/crystalizes into ice some energy is released, when molten heavy metals (iron and nickel) turn solid regardless of the precipitating conditions, they must release some energy and in this case a tremendous amount. Furthermore, one has realize that the water-ice model may be misleading as water behaves differently in these thermo-genic processes. For example, solid water melts under pressure, whereas other substances solidify. Nevertheless, the fact that Ice melts under pressure, is indicative that under pressure all substances release energy.

    3. The pressure from outer layers of Earth applied to the inner layers also generates heat, the same way a piece of ice melts under pressure or a nail head becoming hot under the pounding force of a mallet. Therefore, a second source of Earth’s internal heat seems to be from the gravitational force applied to the entire Earth’s mass with an exponentially increasing pattern towards the center. This mechanism, therefore can contribute by a significant share to the Earth’s overall internal heat.

    4. A third mechanism, a frictional one, can also be surmised that may contribute a great deal to the internal heat of the planet, but not of the same type that is currently proposed. This frictional mechanisms, pertains to the differential rotation of the solid inner core against the molten outer core and that of molten outer core against the outer mantle and the crust. The driving force behind this force is the rotational movement of Earth around its own axis at a relatively high speed (1660 Km/ hour) at the surface which is reduced centripetally to a slower pace. As such, the solid inner core particularly grinds against the molten outer core to generate a magnetic field, an electrical field and or energy and a tremendous amount of heat due to friction.
    I really appreciate if these questions and opinions are posed to the scientific community for verification.

    Respectfully,

    Asad Abrahamian, DVM, Ph.D.
    (اسد ابراهامیان)

    Link to this
  2. 2. babuuu 7:55 pm 02/12/2014

    umm this is an article about hacking websites. what the fuck is this doing here asad?? idiot lol

    Link to this
  3. 3. mountaineers21 10:29 pm 02/12/2014

    This blog was very informational,It is quite alarming to see how easy it is for people to hack into computer systems. This blog was an eye opener to keep all and any personal information that you do mot want others to see off of the internet. Hackers can become skilled and do get into computer systems easily , retaining personal information. I believe that there are various ways to crack down on these hackers. Maybe if there were harsher punishments for hacking into computer systems people it would eliminate some of the fraudulent activity. Also, I believe that in the future there may be stronger protection and ways that this activity can be stopped.

    Link to this

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