Get awesome info about Cyber Attacks: Wireless Attacks

Wireless networks are everywhere, from the home to corporate data centres. They make our lives easier by avoiding bulky cables and related problems. But with these benefits comes a threat: wireless networks are prone to attacks. This article discusses techniques to protect FOSS networks, which systems administrators can implement to achieve adequate security.

Before we talk about wireless security and vulnerability attacks, we must understand the basic radio transmissions, and the IEEE 802.11 protocol, also commonly known as the WLAN protocol. This protocol links two or more devices over a short distance, using spread spectrum signals. Spread spectrum, at its core, is based on radio communication frequencies to establish point-to-point wireless communication between a transmitter and a receiver, while achieving resistance to signal jamming and signal fading. As shown in Figure 1, to establish a wireless network, you need a wireless access point (AP) and also a wireless adaptor for each node to be connected. The AP is also called a hot-spot; it hosts a radio transceiver similar to a walkie-talkie. It also contains hardware to convert digital data into radio signals and vice-versa.

The AP has a unique feature called a beacon transmission, whereby it keeps transmitting a digitized signal, typically, a few times every second. This signal contains the network identification data, the service set identifier (SSID) and some trivial error-correction information. Nodes such as laptops or other wireless devices detect this signal in order to show it in the list of available wireless networks. It also detects whether or not the AP is using any security, the level of the security protocol, etc.

The AP contains a TCP/IP stack, which responds to ARP requests when a node tries to connect to it. Since wireless networks can allow multiple nodes, it is essential to have an authentication layer prior to letting data transfer take place. It is the APs responsibility to ensure this security, as well as to monitor packet transmission and data integrity.

Wi-Fi security: Since wireless networks don’t have built-in security mechanisms, a secure layer on top of the wireless protocol stack is achieved by encryption and authentication techniques such as WEP (Wired Equivalent Privacy) or WPA (Wi-Fi Protected Access). This is especially important because, unlike a wired network, wireless signals can be easily intercepted using a signal-trapping device. Let’s discuss how these encryption techniques work, in detail.

To establish a secure channel, the client first sends an authentication request to the AP, and receives a challenge from it in text form. The client encrypts this text using the preconfigured key and sends it back. The AP decrypts it, and when it succeeds, replies to the client. If the keys don’t match, the request is dropped, and the client cannot connect to the AP. This method is called pre-shared authentication. In an improved version, the shared key is combined with the SSID of the wireless AP, to further toughen the encryption key logic. WEP encryption uses the RC4 algorithm on all packets that travel between the AP and the node. Unfortunately, these security mechanisms are either flawed by design, or are not adequate for IT infrastructures where data carried on wireless channels is sensitive.

With this basic understanding of Wi-Fi security, let us now discuss a few security attacks. In general, there are four categories of possible attacks.

Passive attacks: In this type, the attacker listens or eavesdrops on an open wireless channel by using a wireless modem rigged to work in a promiscuous mode. All traffic packets that contain important information, such as MAC addresses, packet sequences, etc, are stored. Passive attacks may not necessarily be malicious in nature, but help provide information for active attacks. Since passive attacks take place silently, they are almost impossible to detect and stop. Attackers using passive methods usually capture and store data, and use a packet-deciphering tool to decrypt it and steal information. This is especially true in case of the WEP protocol, due to its inherent lack of security. Passive attacks are also called wireless war-driving.

Active attacks: Once an attacker gets sufficient information by passive attacks, an active attack can be tried. Common examples are denial of service, IP spoofing, etc. In case of spoofing, the attacker gains access to an unauthorized wireless station, and performs packet crafting to impersonate a valid and authorized station. Wireless nodes are incapable of detecting this, and end up connecting to the attacker’s station and revealing information. By extending this technique, the attacker can now plant a denial of service attack on a particular node in order to disrupt its services. Typically, a SYN flood method is used, because it is sufficient to generate a packet storm on the given wireless connection bandwidth.

MITM attacks: We did explore man in the middle (MITM) attacks in one of the previous articles and most of that applies to wireless networks as well. The only technical difference here is that the attacker gains information of an actively used SSID of an AP, instead of an on-the-wire session. As shown in Figure 2, a dummy AP with exactly the same name is created by the attacker, and the signal power is raised to such an extent that the nodes are fooled into believing that it is the AP they should connect to. This creates an MITM situation. These dummy APs, also called rogue points, are usually set up close to the nodes to be hacked.
Signal-jamming attacks: Unlike the above techniques, this method uses wireless radio transmission techniques to create an attack. In this type, the attacker uses a powerful antenna and a signal generator, and creates frequency patterns in the same range as wireless signals. The frequency patterns are modulated with powerful radio frequency ripples, to create a wireless signal storm. This results in the jamming of the APs as well as the nodes, thus disabling their connectivity. While such an attack was just a theory previously, with a growing number of wireless networks these attacks have now occurred more often than earlier.
Besides these, there are a few other types of attacks, some of which make use of one or more of the attacks mentioned above.

802.11 injection attacks: Modern attackers tend to go deep into the protocol stack in order to plant an attack. For wireless networks, an attacker can first perform a passive attack to understand the protocol frame structure, and then create 802.11 protocol datagram frames and insert those into the network. This is usually done either to create a false packet stream as a hindrance for a wireless network, or to sniff the network further in an active mode. The response 802.11 frames are then captured again, interpreted and modified to perform an MITM attack. Since this attack happens at Layer 2, it is very tough to detect.

Wireless packet injection: Here, passive attacks are used to capture traffic, which is then analysed. However, there can be situations in which there won’t be enough traffic to generate sufficient data, which can lead to time-consuming or futile hacking efforts. Hence, attackers use wireless packet injection techniques whereby, besides the 802.11 frames, IP datagrams are sent to the target AP. Though the AP will drop such packets as unauthorised, this gives the attacker the necessary amount of traffic, which is captured and fed into key-cracking utilities. Since the attacker controls the packet-generator utility, specific data patterns are intentionally created to map the APs behaviour in terms of response packets, which further helps in reducing the cracking time.

PSK guessing: As we learnt earlier, a pre-shared key is used between the wireless AP and node to encrypt communication. Typically, administrators setting up Wi-Fi networks tend to leave the vendor-provided default key in place. Smart attackers usually first try to detect the manufacturer of wireless APs, and if that information is not available, they try to guess it and attempt to break the key.

Key cracking: Usually a pre-shared key should be enough to establish security. However, in case of WEP-based Wi-Fi networks, attackers can use passive methods to sniff and capture a lot of data, and subject it to key-cracking algorithms. As we saw earlier, WEP is a simple RC4 XOR type of encryption, and it only takes some amount of time to break into it. It had been demonstrated by attackers that a packet capture of more than 40000 can be sufficient data to crack a WEP key in minutes. With the introduction of WPA security features in a wireless AP, it became tough to break the key. However other brute-force attacks, such as statistical key guessing, dictionary attacks, etc, can be used to crack it.

Wireless attack detection: Before we talk about protecting the infrastructure, it is imperative to understand a few detection techniques. Unlike wired networks, a wireless network signal can be compromised easily, which makes detection difficult but certainly not impossible.

AP monitoring: As we learnt, securing the SSID of an AP or wireless router is very important. In a large organisation, keeping track of SSIDs can be a challenge; hence, this information should be programmatically stored in a secure database. Other crucial details, such as the MAC ID, IP restrictions, the wireless channel used, the beacon settings, wireless signal strength and bandwidth type are stored for each corresponding SSID. A wireless monitoring device, or a mobile device running monitoring software, is used to detect all stations and APs periodically, and the results are compared with the baseline database created earlier. Such routine audits ensure the integrity of router settings and thus the overall wireless network security.

Wi-Fi node monitoring: Along with the APs, each node needs to be monitored too. The technique is a bit different, though. For the nodes, a MAC-based security on the APs can be configured, whereby a particular AP would support only a set of MAC addresses. This ensures that the wireless client node cannot roam around beyond the configured zone, and if such a need arises the request can be fulfilled via an authorisation and approval process. For large organisations, this can result in systems administration overhead, in which case the nodes can be allowed to connect to all APs; however, each connection and disconnection can be logged and parsed for anomalous behaviour.

Traffic monitoring: Besides the above techniques, network administrators can periodically take samples of data from each AP, and check for denial of service and SYN flood attacks. Multiple connections and disconnections on a particular AP from one or more client nodes should also trigger a warning. As for Layer 2 attacks, a signal spectrum detection tool can be incorporated too, to detect signal-jamming situations. 
Protecting FOSS systems: Along with the monitoring techniques, additional security measures are essential. For small networks, changing the default password and SSID of the AP is a must. Modern routers are equipped with a feature to disable the broadcasting of SSID, which should be turned on to ensure that passive sniffing attacks are thwarted to some extent. Periodically changing SSIDs is highly recommended, though it can be a tough task for a large number of wireless APs. To protect a Linux server farm hosted in a data-centre, the wireless signal strength of APs should be adjusted in such a way that it should be adequate for client nodes to connect and transfer data seamlessly, but at the same time it should not cross physical building boundaries, whereby it can be detected by a drive-by attacker.

Using WPA2 security instead of WEP is recommended. Besides, the shared key of WPA security should be long and complex enough to stop directory brute-force attacks. For large corporations, the Layer-7 wireless security software should be installed on client nodes as well as APs, to further strengthen the encryption process. For FOSS systems, using an X.509 certificate on either end of the wireless communication can help achieve cheaper yet effective security. Most famous flavours, such as Debian and Ubuntu, support WPA2 security with trimmings such as AES, TKIP and LEAP. Configuring those, along with MAC address filtering, and enabling firewall features can protect a serious server farm, yet let it enjoy the benefits of wireless networks.

Wireless attacks are, unfortunately, easy to carry out and difficult to detect. Modern data centres allow the presence of wireless networks connected to the product server farms, thus requiring the implementation of security measures. While there is no single solution to protect wireless networks, an appropriate combination of the techniques mentioned above can achieve adequate security. Wireless monitoring audits are an important activity that needs to be done by network administrators at regular intervals.

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Interesting overview about Sleeping and Eye contact

1. Humans spend a third of their life sleeping (25 years or more).
2. Humans can survive longer without food than they can without sleep.
3. During the first two years of a baby’s life, new parents will miss six months of sleep on average.
4. In 1894, Russian scientist Marie Mikhaïlovna de Manacééne conducted one of the earliest experiments on extreme sleep deprivation. She found that when she deprived puppies of sleep, they all died within four or five days, despite every effort to keep them alive. The younger the puppy, the more quickly it died.
5. Giraffes sleep only 1.9 hours a day in five- to 10-minute sessions. Koalas, however, are the longest-sleeping mammals, sleeping up to 22 hours a day.
6. The word “sleep” derives from the Proto-European base sleep, “to be weak,” and is related to “slack.” “To sleep around” was first recorded in 1928.
7. Sleep is a universal characteristic of complex living organisms and has been observed in insects, mollusks, fish, amphibians, birds, and mammals.
8. Only one half of a dolphin’s brain goes to sleep at a time. Dolphins are capable of what is known as uni-hemispheric sleep, in which one hemisphere of the brain goes into a deep sleep while the other hemisphere remains awake. This allows dolphins to sleep under water without drowning. Dolphins spend approximately one third of their lives asleep.
9. Slow-wave sleep appeared about 180 million years ago. REM sleep is believed to have appeared 50 million years later. Humans most likely developed a monophasic sleep/wake pattern in the Neolithic period (10,000 B.C.).
10. In Greek mythology, Hypnos (Somnus in Roman mythology) was the god of sleep. Thanatos, or death, was his twin. Poppies and other sleep-inducing plants grew at the entrance of Hypnos’ cave.
11. Heart disease, diabetes, and obesity all have been linked to chronic sleep loss.
12. There are at least 84 identified sleep/wake disorders.
13. During the night, we move back and forth between quiet sleep and deeper, active sleep. We go through four or five 90- to 110-minute rounds of this basic quiet/active sleep cycle each night.
14. The invention of the light bulb affected human sleep patterns .The average amount of time people sleep has dropped from nine hours in the pre-light bulb era to seven-and-a-half hours today.
15. Ken Parks, who murdered his mother-in-law by bludgeoning her with a tire iron and attempted to murder his father-in-law by strangulation, offered sleepwalking as a defense during his trial. He was acquitted.
16. Each year, sleep-related errors and accidents cost U.S. businesses an estimated $56 billion, cause nearly 25,000 deaths, and result in 2.5 million disabling injuries.
17. Over 70 million Americans suffer from a sleep disorder. Of those, over 60% have a chronic disorder.
18. When applied patiently and systematically, sleep deprivation is said to be the single most effective form of coercion and torture.
19. A nineteenth-century Chinese merchant was sentenced to death for murdering his wife. Sleep deprivation was deliberately chosen as the method of execution on the grounds that it would cause the maximum amount of suffering and would serve as the greatest deterrent to other potential murderers. He eventually died on the nineteenth day, having suffered terribly.
20. People whose normal nightly sleep duration is either unusually short (less than four hours) or unusually long (more than nine or 10 hours) have a higher-than-average risk of dying prematurely.
21. A person’s core body temperature drops to facilitate the onset of sleep. This means that artificial heat sources, such as electric blankets, can negatively affect a person’s quality of sleep.
22. The phenomenon of sudden, unexplained death of adults during sleep is called SUDS. In the Philippines it is known as bangungut, which literally means “to rise and moan during sleep.”
23. Sleepwalking is also called somnambulism, from the Greek somnus (sleep) + amb (to walk). Most sleepwalkers remember little, if anything, about the experience. While sleepwalking, a person can sometimes use the bathroom, eat, or even talk. Scientists postulate that adult sleepwalking has a genetic component.
24. Studies show that less sleep (six hours or less) can lead to higher inflammatory proteins in the blood.
25. Western industrialized societies have such high numbers of sleep deprivation that what is abnormal sleepiness is now considered normal. Sleep deprivation is often considered normal.
26. Over two million children suffer from sleep disorders.
27. During sleep, the brain “consolidates” memories and skills, meaning that the brain strengthens, reorganizes, and restructures memories during sleep.
28. The National Highway Traffic Safety Administration reported that being tired accounts for the highest number of fatal single-car run-off-the-road crashes—even more than alcohol.
29. People who are in a coma or under anesthesia may seem to be asleep but the complex, active brainwave patterns seen in normal sleep are absent.
30. Rats normally live from two to three years. However, those deprived of REM sleep survive only about five weeks, and rats deprived of all states of sleep live only about three weeks.
31. The “exploding head syndrome” is a disorder in which when someone wakes up, they feel the sensation of an explosion going off in the head. This disorder typically occurs in the elderly. The syndrome causes anxiety, rapid heart rate, and sweating.
32. REM atonia, or sleep paralysis, occurs in the typical sleeper every night to prevent people from acting out their dreams. Only a few muscles have the ability to move during REM sleep, such as the eye muscles, the auditory muscles, and the diaphragm for respiration.
33. We usually spend more than two hours each night dreaming. We dream at least four to six times a night.
34. Experts say that if someone feels drowsy during the day, even during boring activities, they have not had enough sleep. Additionally, if a person falls to sleep in less than five minutes after lying down, they are suffering from severe sleep deprivation.
35. Children don’t react the same way to sleep deprivation as adults: while adults get sleepy,children become hyperactive. In fact, a lack of sleep can result in ADHD-like symptoms in kids. Children need an average of nine to 10 hours of sleep each night.
36. Sleep-deprived children often become hyperactive.
37. Patients with erectile dysfunction (ED) are twice as likely to suffer from sleep apnea.
38. The Greek writer and philosopher Alcmaeon (fifth century B.C.) proposed what is probably the first theory on the causes of sleep. He postulated that sleep occurred when the blood vessels of the brain filled with blood. The blood induced pressure on the brain, which created sleepiness. When the blood left the brain, a person would wake up.
39. Aristotle (384-322 B.C.) proposed that sleep occurred as long as digestion took place. The fumes from the food were absorbed into the blood stream, which were then taken to the brain, where they induced sleepiness.
40. Shakespeare made many references to sleep in his writings, and his clear descriptions of insomnia suggest that he suffered from the disorder.
41. A malingerer is someone who pretends to have a sleep disorder in order to get medication or other attention.
42. Fifty percent of women with children agree that sleep is the best way to recharge. This is nine percentage points higher than women without children.
43. Sixty-five percent of Americans lose sleep because of stress.
44. The Sandman is a mythological personification of sleep. The term developed from the “sand” that is commonly found in the corner of the eyes

“Each and Every living organism has been to Sleep. In human life he took_____ days for Sleeping (Approximately).”

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Neno laser using single automic sheet

Scientists have built a new nanometer-sized laser using a semiconductor that's only three atoms thick. It could help open the door to next-generation computing that uses light, rather than electrons, to transfer information.

 

University of Washington scientists have built a new nanometer-sized laser -- using the thinnest semiconductor available today -- that is energy efficient, easy to build and compatible with existing electronics.

Note: The ultra-thin semiconductor, which is about 100,000 times thinner than a human hair, stretches across the top of the photonic cavity.

Lasers play essential roles in countless technologies, from medical therapies to metal cutters to electronic gadgets. But to meet modern needs in computation, communications, imaging and sensing, scientists are striving to create ever-smaller laser systems that also consume less energy. The UW nanolaser, developed in collaboration with Stanford University, uses a tungsten-based semiconductor only three atoms thick as the "gain material" that emits light. The technology is described in a paper published in the March 16 on-line edition of Nature.

"This is a recently discovered, new type of semiconductor which is very thin and emits light efficiently," said Sanfeng Wu, lead author and a UW doctoral candidate in physics. "Researchers are making transistors, light-emitting diodes, and solar cells based on this material because of its properties. And now, Nanolaser."

Nanolaser -- which are so small they can't be seen with the eye -- have the potential to be used in a wide range of applications from next-generation computing to implantable microchips that monitor health problems. But nanolaser’s so far haven't strayed far from the research lab. Other nanolaser designs use gain materials that are either much thicker or that are embedded in the structure of the cavity that captures light. That makes them difficult to build and to integrate with modern electrical circuits and computing technologies.

The UW version, instead, uses a flat sheet that can be placed directly on top of a commonly used optical cavity, a tiny cave that confines and intensifies light. The ultrathin nature of the semiconductor made from a single layer of a tungsten-based molecule yields efficient coordination between the two key components of the laser. The UW nanolaser requires only 27 nanowatts to kick start its beam, which means it is very energy efficient. Other advantages of the UW team's nanolaser are that it can be easily fabricated, and it can potentially work with silicon components common in modern electronics. Using a separate atomic sheet as the gain material offers versatility and the opportunity to more easily manipulate its properties.

"You can think of it as the difference between a cell phone where the SIM card is embedded into the phone versus one that's removable," said co-author Arka Majumdar, UW assistant professor of electrical engineering and of physics."When you're working with other materials, your gain medium is embedded and you can't change it. In our nanolaser, you can take the monolayer out or put it back, and it's much easier to change around," he said.

The researchers hope this and other recent innovations will enable them to produce an electrically-driven nanolaser that could open the door to using light, rather than electrons, to transfer information between computer chips and boards. The current process can cause systems to overheat and wastes power, so companies such as Face book, Oracle, HP, Google and Intel with massive data centers are keenly interested in more energy-efficient solutions. Using photons rather than electrons to transfer that information would consume less energy and could enable next-generation computing that breaks current bandwidth and power limitations. The recently proven UW nanolaser technology is one step toward making optical computing and short distance optical communication a reality.

"We all want to make devices run faster with less energy consumption, so we need new technologies," said co-author Xiaodong Xu, UW associate professor of materials science and engineering and of physics. "The real innovation in this new approach of ours, compared to the old nanolaser, is that we're able to have scalability and more controls."

Still, there's more work to be done in the near future, Xu said. Next steps include investigating photon statistics to establish the coherent properties of the laser's light.

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