IP spoofing

IP spoofing

Various organizations are facing different types of cyber-attacks these days which have a serious negative impact on the proper functioning of those companies. And Spoofing is one of them. Spoofing is the act of disguising itself as someone known in the network. Spoofing can be applied to emails, phone calls, websites, and even IP addresses. IP spoofing creates IP packets and sends them in the network by modifying the source IP address in order to hide the identity of the sender or for impersonating another computer system or even both.

The primary way of communicating in the network is actually by sending and receiving the packets. The IP packet consists of header and payload (i.e. body). The header of the IP packet consists of the IP version, source IP address, and destination IP address while the payload consists of the actual information to be sent. The source IP address is the address of the sender and the destination IP address is the address of the receiver. In order to communicate, the sender sends the packet to the destination computer and receives the response after the receiver has received the packets. These packets are spoofed by forging the source IP address.

The attackers uses IP spoofing to overwhelm the computer services with packets of data ultimately shutting them down. There are mainly two ways to overload the traffic of the target computer using IP spoofing. The first one is to flood the selected target with the packet from multiple spoofed addresses by sending victim tons of data making them unable to handle. This is a direct method of IP spoofing. The second method is an indirect one. Here the packets are sent to many different recipients on the network using the spoofed IP address. The attacker disguises to be the target computer and send packets to other devices. Since the spoofed packets appear to be from the target’s computer, all the responses are sent to the target’s computer causing floods of packets on the target’s computer.

Illustration of the concept

The received spoofed packets appear to be from a legitimate source. In some of the networks, trust relationships are in place between machines and internal systems. In this type of network, IP addresses are used to verify machine identities to access the systems rather than user login. This type of authentication is known as IP address-based authentication. The IP spoofing method is used by attackers sometimes to bypass IP address-based authentication. There are several types of attacks that are launched through IP spoofing. Blind spoofing, Non-blind spoofing, DDoS attacks, man-in the middle attacks are some examples.

Illustration of the concept

Spoofed packets are difficult to be detected as the source IP address seems to be authorized. But there are various preventive measures that can reduce the possibility of IP spoofing. Key-based authentication should be used rather than IP address-based authentication. This will reduce the risk of spoofing. If possible, configuring routers and switches to reject packets originating from outside the local networks but claiming to originate from within will not allow the spoofed packets to enter the network.

IP spoofing is a cyber-attack that shuts down the target’s computer by flooding it with tons of spoofed packets. The attackers will have unauthorized access over the computers and networks, and in certain cases, IP spoofing may have negative impacts on the business and economy of some organizations where computers are responsible to provide services. However, IP spoofing is not always considered to be illegal. Sometimes VPN service is used or IP address is changed in order to browse the internet safely. But IP spoofing will be illegal if it is used to harm others or someone pretends to be someone else and commits cybercrime.

Article by:

Shreya Shrestha

CS-2nd year



Black holes are one of the most amazing and intriguing things that we can find in our entire universe. You might be curious to know its attributes. In short, black holes are the last state of a massive star, in which the core collapses within itself due to immense gravity to form a funnel in space-time, which never ends. 

This guy sounds awesome — let us get a picture of it! Well, not so fast. No particle or even electromagnetic radiation such as light can escape from it, which makes it impossible to observe.

Despite such traits, this bad boy leaves traces of a ring of light of hot plasma zipping around it, which reveals the black hole’s event horizon. Einstein’s equation predicts the shape and size of this ring, and acquiring its picture will help to verify that those equations holds the extremist of the conditions in the universe. Now, without further ado, let’s get the picture of the traceable sides of a black hole.
Again, hold your horses! Black holes are so far away from us that these rings will appear astronomically small from the earth. It’s like taking a picture of an orange on the surface of the moon. 

We have an equation:

smallest size = wavelength/telescope size

The equation says, “In order to see smaller objects we need to make our telescope bigger and bigger”. Again, even with the assistance of the most powerful telescope on earth, we cannot reach close to it. For reference, Figure: 1 is the highest resolution image ever taken of the moon, and it contains roughly 13000 pixels. However, you can nearly fit 1.5 million of those balls of vitamin C in a single pixel. So, how big of a telescope do we need to see an orange on the moon’s surface? The answer is 510.1 million km squared. You guessed it right! It’s the size of the earth! It is almost impossible to create such a thing unless you are a green guy with a UFO.

Figure 1: Highest Resolution photograph of Moon

What can we do? It turns out that we can use the magic of computers to create a computational telescope that is the size of the earth, just to take the picture. To do so, we will scatter some powerful telescopes around the globe and synchronize each of them with precise atomic clocks. These telescopes will work together to freeze lights at those instances to collect terabytes of data simultaneously (remember those atomic clocks). To make it more elegant, imagine the earth as a large spinning disco ball as in Figure 2. Now, imagine those telescopes are the individual mirrors like those disco balls, which collects light individually and then combines it to create a full picture. Though covering the whole planet with those mirrors is difficult, but, we can fill them in little spaces and use earth’s rotation to observe different parts of the image. Despite those clever tricks, there will still be gaps in the image; however, we can solve this problem by using advanced algorithms to fill those gaps.

Figure 2: Disco Ball Analogy

Did we take its picture yet?

Well technically speaking, the answer to this question is a big yes and even a big no! We can only see some samples, but there is an infinite number of possible images that are consistent with our results. Now, this is where computer science shines! We can create algorithms that can find the most reasonable image fitting our results. Those algorithms can be considered as a forensic artist who creates the face of the criminals using descriptions. The algorithm ranks the possible images and chooses the most likely image. But here’s the bummer — we have never seen black holes before. What should we assume about the structures of the black holes? We could take a little help from Einstein’s equations, but we still want the picture of what is really happening! If we relied upon Einstein too much then we will get a biased result. In other words, we would like the option open for a giant alien Vacuum cleaner to exist inside a black hole. One way to solve this problem is to impose the features of different kinds of images and see if we get the same results each time. It’s like giving the same description to different sketch artists around the globe, and if all of them produce similar faces then we can be more confident that there are no biasness. Finally, (the drum roll please!) we can complete this puzzle by putting together all of those pieces and obtaining the picture of the bad boy of the universe.

If you are planning to make a run for the Nobel Prize using this ingenious technique, then you are a bit late. On 10th April 2019, a group of dedicated astronomers, physicists, mathematicians, and engineers of Event Horizon Telescope revealed the first-ever picture of a black hole (Messier-87). Similarly, Katherine L. Bouman, a graduate-level computer science student at MIT, was credited for the development of such a powerful algorithm. Without her immense contribution, achieving this milestone would not be possible.

Figure 3: Katherine L. Bouman

Bibliography: Event Horizon Telescope, TED

Images: NASA, Event Horizon Telescope, Google images

Article by
Anurag Timilsina

Computer Engineering 1st year

KU as Hogwarts and Computing as Wizardry

KU as Hogwarts and Computing as Wizardry

If coders were wizards, their coding skills would be their wands and their codes would be the spells they cast. The magic here would be their creations!

Being the student of DoCSE here at KU, hovering around this ‘if’, we could say that we chose KU to be our Hogwarts to learn the magic of the computing world. If KU was my Hogwarts, I would find Platform 9 3/4s at Ratna Park as my King’s Cross Station

Where would you find your Platform 9 3/4s?

I have often wondered if a huge black dog that shows up at KU was an Animagus, Sirius Black and the pigeons that show up all the time at the top of our block if you have noticed, were our version of owls. But, thank god, I have not encountered any Peter Pettigrew as any of my friend’s pet or any Moaning Myrtle in the bathroom.

For many of us in the first semester, COMP 101(C Programming Language) would definitely be the Defense Against The Dark Arts, the most interesting one and in the second semester, PHYS 102 (the one with gradients, curl and divergence) would definitely be the Potions, the toughest one. Metaphorically, for me and my classmates, Manoj Sir, who taught us C, would be Professor Lupin and Ganesh Sir, who taught us Physics would be Professor Snape

What about you people?

You know, what would be more interesting with this ‘if’? Our block 9 could be the Hogwarts Castle and could have The Chamber of Secrets. And who knows, one of us could speak Parseltongue with the snakes we keep seeing while chilling at the fountain near our block. The KU canteen could be the Great Hall, where we dined together. The administration block could be the Shrieking Shack of KU. That way, Harry Potter would get to know his godfather in the KU corner. Moreover, IT Meet could be our Quidditch Cup and IT Park our battlefield
Competing teams, you better work hard if you want to grab a Snitch!

Sadly, having an Invisibility Cloak or a Marauder’s Map is quite impossible in our world. And what’s worse is that the dementors would try to suck happiness from our soul at the times of pressure due to assignments and exams. 
So, wizards, be prepared with your Patronus Charm!

Being a potterhead, I can go on and on about this imaginary wizard world at KU, and those of you who could relate, may want to add some of your imaginations too, here. However, this needs an end; an end that we can learn something valuable from. So, in order to wrap this article up in the most serious and inspirational way possible, I want to emphasize on two major things. First, there is no Sorting Hat in our world. We must recognize our strengths on our own. Second, as I said earlier, our skills are our wands, but, unlike in Harry Potter’s world, neither some Ollivander will be making any wands for us, nor those wands would choose any metaphorical wizard of a real world. Instead, we must choose and build our own wands, our own set of skills.

Finally, as a believer of magic in this real world, only one thing remains to be said, ‘Explore the magic in you, and be the wizard you have always wanted to become!’