Tag Archives: Technology

Igneous Rocks and Magma

1) Introduction

Igneous rocks are defined as those rocks which have crystallised
from a silicate melt (magma) either within the Earth or at the surface. If the magma cools at depth, slow cooling will occur and a coarse-grained igneous rock will result. If cooling is more rapid, a medium-grained rock is formed ( for example at shallow depths – the hypabyssal environment – sills, centres of dykes), and if the magma erupts at the surface, cooling is very quick so a fine-grained volcanic, rock is formed. With very rapid chilling, a volcanic glass can be formed (obsidian).

Magma contains dissolved gases that remain in solution under pressure. When the pressure is released this can lead to an eruption. This pressure release is called exsolution. Such a process can lead to a fragmental or frothy rock being erupted called a pyroclastic eruption. Magma erupting underwater (sea, lake) produces characteristic shapes known as pillow lavas. These have glassy chilled margins with interiors full of holes, where gases were exsolved but trapped within the rock. The holes are termed vesicles (the sites of former gas bubbles) and are also common in lava flows.

Magmas intruded into small fissures near the surface of the Earth form dykes if vertical and discordant to the bedding, and sills if near horizontal and concordant with the bedding. These dykes and sills may have chilled margins and coarser interiors, and often show cooling joints perpendicular to the cooling surfaces.

2) Classification of igneous rocks

Igneous rocks may be classified using grain-size.
This classification roughly corresponds to plutonic, hypabyssal and volcanic environments. The crystals of coarse-grained rocks can be seen easily with the naked eye; those of medium-grained rocks need a hand-lens; those of fine-grained rocks require a microscope to be resolved.

Some igneous rocks show evidence of having undergone two stages of cooling. The magma may pause en route to the final place of intrusion or extrusion, and cool slightly. Crystals will form and grow. Subsequently eruption or final intrusion takes place and the remainder of the magma will crystallise with a generally finer- grained texture. So we see large crystals (termed phenocrysts) in a finer-grained matrix (called the groundmass). This is known as porphyritic texture.

Igneous rocks can also be classified using mineralogy and chemistry. Textural terms (above) are also useful because the same magma (for example a magma of basaltic composition) can crystallise under different conditions to give very different looking rocks. The chemical composition of the rocks will be the same, and the mineralogy may or may not be similar depending on the physical history, but the rocks may look very different.

3) Chemical definitions

Chemical analysis of igneous rocks gives a classification according to their chemical compositions. A common classification is based on the amount of silica in the rock. Note that this is the chemical amount of silicon dioxide (SiO2), not the quantity of the mineral quartz.

4) Mineralogical definitions

Igneous rocks are composed of varying percentages of mafic (ferromagnesian) minerals such as olivine, pyroxene, amphibole, biotite mica, and felsic minerals such as plagioclase, alkali feldspar and quartz. Generally, mafic minerals tend to be dark in colour and felsic ones light in colour, although this is not always the case.

The percentage of mafic minerals in a rock is called the Colour Index (C.I.) A high colour index is associated with ultrabasic and basic rocks containing >50% mafic minerals. These rocks are sometimes referred to as melanocratic. Colour indices of 30 – 50% are referred to as mesocratic, and are associated with intermediate rocks, while a low C.I. of <30%, referred to as leucocratic, is associated with acid rocks. Do not be led astray by the black obsidian glass which is not a mafic mineral.


http://www.geologyin.com/2014/07/texture-of-igneous-rocks.html

We define igneous rocks using a combination of the percentages of quartz, alkali feldspars, plagioclase feldspars and ferromagnesian (mafic) minerals. Grain size also plays a part in naming igneous rocks.

Ultramafic rocks; These contain nearly 100% ferromagnesian minerals.

Dunite is a rock which is rich in the mineral olivine. Pyroxenite is a rock rich in the mineral pyroxene. Peridotite is a rock consisting mainly of olivine and pyroxene. All of these are intrusive rocks and therefore have a coarse or medium grain size. Extrusive rocks of this composition and mineralogy are called komatiites. These are rare today, but more abundant in the early history of the Earth when the mantle was hotter.

Basic rocks:

Basic rocks contain approximately 50% plagioclase (composition typically of labradorite >An50) and 50% mafic minerals (pyroxene). Olivine may also be present, in which case we can preface the name of the rock with the mineral name, for example, olivine basalt. Coarse-grained rocks of this composition are called gabbros; medium-grained ones are dolerite, and fine-grained ones are basalts.

Intermediate rocks:

The diorites are characterised by felsic minerals such as plagioclase (usually andesine), and ferromagnesian minerals (mafics) which may include hornblende and biotite (rarely pyroxene). The ratios are generally such that plagioclase is more abundant than mafics. Quartz and alkali feldspars also may be present. In coarse-grained form they are termed diorite or quartz diorite, and when fine-grained, andesite or dacite.

Acidic rocks:

Quartz and alkali feldspar are abundant (>50% of the total). Plagioclase is andesine or oligoclase. Alkali feldspar includes albite, microcline, orthoclase. Mafic minerals are less abundant and are commonly biotite or hornblende. Muscovite (white mica) also occurs in some granites. Coarse-grained rocks of this composition are called granodiorite or granites and fine-grained varieties are rhyodacite or rhyolite. Other types occur depending on the cooling history.

The relationship between SiO2 and the relative proportions of different minerals is illustrated by a diagrammatic model. If a sample has 50% silica, then using the model it could be ascertained that it should contain 5% olivine, 70% pyroxene and 25% plagioclase feldspar. If it is coarse-grained it would be a gabbro and if fine, a basalt.

5) Origin of basaltic magmas

Magmas are formed by the melting of pre-existing rocks. This occurs in the upper mantle, perhaps where water has lowered the melting temperature. The upper mantle is composed of peridotite.


http://www.geologyin.com/2014/07/texture-of-igneous-rocks.html

Peridotite is a complex solid, commonly consisting of 4 minerals (olivine, clinopyroxene, orthopyroxene and spinel or garnet). Each of these minerals melts at a different temperature and so peridotite does not completely melt at any single temperature.

As the temperature rises, some minerals melt and others remain solid. The melting process is aided by the presence of water or by the release of pressure. The parts that melt first (consisting of the minerals with the lowest melting points) rise to higher crustal levels to become rocks of different overall compositions.

Mantle peridotites have been subjected to melting experiments at appropriate pressures in the laboratory, and basaltic magmas are produced in such experiments. Therefore, low P and S wave velocities in the upper mantle are attributed to local basaltic melts. The process of melting a solid to form a melt of different composition is called partial melting.

Evolution of magmas:


http://www.geojeff.org/evolution-of-magmas.html

Once basaltic magmas have been formed by partial melting of the mantle, they rise upward towards the surface of the Earth. This is due to their buoyancy arising from the lower density of the partial melt than that of its parent. During the process of rising magmas cool and crystals begin to form. If these crystals are removed from the melt (for example they fall to the floor of the magma chamber) or are otherwise prevented from continuously reacting with the magma (formation of zoned crystals), then the magma will change in composition. This is the process of fractional crystallisation and it leads to the formation of families of related igneous rocks (sometimes called a suite or a rock series). Rocks such as basalts, andesites, dacites and rhyolites may all be erupted from a volcano beneath which a magma chamber is undergoing fractional crystallisation.This process can be repeated until acidic rocks (rhyolites) are formed. However, most granitic magmas are probably formed by another process: partial melting of crustal rocks.

Sources and References:https://giphy.com/gifs/12442m0WZFHvuE
http://www.geologyin.com/2015/01/the-relationship-between-igneous-rocks.html
http://www.geologyin.com/2014/07/texture-of-igneous-rocks.html
http://www.geojeff.org/evolution-of-magmas.html

Blog:
https://thegeekiestone.com/

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Earth Vs Venus – November 2017

A Lecture I attended a last year! Found the video by the Geological Society of London!

Copied Video’s Description:
Why Earth developed into the crucible of life, and Venus into a hostile wasteland

The present-day differences in the expression and intensity of volcanism on the planets of the inner solar system serves a testament to the dynamic nature of planetary formation and evolution. For example, Earth and Venus are colloquially referred to as sister planets because of their similar size and composition. However, their contrasting volcanology, atmospheric mass and chemistry, climate, and geomorphology are striking.
In short, the Venusian atmosphere and surface contains five orders of magnitude less water than Earth and the average surface temperature on Venus is 460 °C. In addition, Venus is a relatively flat planet, where only 2% of the surface is shows any appreciable topography. Earth, by contrast, has a wet and cold surface with a bimodal topography (e.g. orogenic belts and ocean basins). Suffice to say, these are not identical siblings.
Here I will show how we can combine data from rock-deformation experiments with the chemistry of the Venusian and Terrestrial atmospheres to explain the flatness and relative volcanic quiescence of Venus. In short, I will outline why Earth developed into the crucible of life, and Venus into a hostile wasteland.
Speaker

Sami Mikhail (University of St Andrew’s)
Dr. Mikhail is a lecturer in Earth Sciences at the University of St Andrews (since May 2015), after spending two years as a Carnegie Postdoctoral Fellow at the Geophysical Laboratory (Washington DC, USA) and a couple of postdoctoral positions at the Universities of Bristol and Edinburgh (UK).
Prior to this Dr. Mikhail gained an BSc in Geology from Kingston University (2006), an MSc in Isotope Geochemistry from Royal Holloway and Bedford New College (2007) and a PhD on the origin of diamond-forming carbon at University College London (2011).
The motivation behind Dr. Mikhail’s research is to understand how the interior of a planet affects and controls the composition of its surface and to long-term habitability. Dr. Mikhail’s approach combines investigations of natural samples with high-pressure and -temperature experiments and theoretical models.
Dr. Mikhail has worked on diverse projects such as the source of Icelandic volcanism, diamond-formation in the deep Earth, and more recently, on linking mantle processes to atmospheric chemistry on Earth, Mars, and Venus.

Geological Society Youtube Channel:
https://www.youtube.com/channel/UCzhX_LOB1xUwIDmckTrPOqw

Lecture Details:
https://www.geolsoc.org.uk/EarthvsVenus17

My Personal Blog:
https://thegeekiestone.com/

The P Versus NP Problem Is One of Computer Science’s Biggest Unsolved Problems

 

In the world of theoretical computer science, P vs. NP is something of a mythical unicorn. It’s become notorious, since it remains an unsolved problem. It basically asks this: If it is easy to check that a solution to a problem is correct, is it also easy to solve that problem? Get back to us when you have an answer. (http://www.claymath.org/millennium-problems)

Why Is This So Hard?

In the P vs. NP problem (http://news.mit.edu/2009/explainer-pnp), the P stands for polynomial and the NP stands for nondeterministic polynomial time. Did we lose you? Let’s back up. In simpler terms, P stands for problems that are easy for computers to solve, and NP stands for problems that are not easy for computers to solve, but are easy for them to check. Here’s when an example might be helpful: “A farmer wants to take 100 watermelons of different masses to the market. She needs to pack the watermelons into boxes. Each box can only hold 20 kilograms without breaking. The farmer needs to know if 10 boxes will be enough for her to carry all 100 watermelons to market.” (https://simple.wikipedia.org/wiki/P_versus_NP)


Behnam Esfahbod / WIkipedia ()

This sample problem is not easy to solve; it requires you to go through every dang possible combination. Checking the final answer, however, is pretty easy. All P problems are also NP problems (if a computer can easily solve it, the computer can also easily check it). The question remains open: Are P problems and NP problems the same type of problem? Or, are there are some problems that are easily verified but not easily solved?

Who Wants To Be A Millionaire—From Math?

You may be wondering who really cares about this sort of thing. Well, if someone could show that P is equal to NP, it would make difficult real-world problems a piece of cake for computers to solve. Oh, and the person who solves this problem would also get $1 million from the Clay Mathematics Institute. The P vs. NP Problem is one of six unsolved Millennium Problems that hold a million-dollar prize for whoever cracks it.

Want to dive even further into the world's toughest math problems? Check out "The Millennium Problems: The Seven Greatest Unsolved Mathematical Puzzles Of Our Time" by Keith J. Devlin. We handpick reading recommendations we think you may like. If you choose to make a purchase, Curiosity will get a share of the sale.

Watch And Learn:
Why is P vs NP Important?

In this video,He explain perhaps the most famous problem in all of Computer Science. Does P = NP? He define the terms and give examples of each. We also programmatically go through the traveling salesman problem. He experiment with a little bit of mixed reality in this video as well.


Sources and References:https://curiosity.com/topics/the-p-versus-np-problem-is-one-of-computer-sciences-biggest-unsolved-problems-curiosity/
https://madatgravity96.wordpress.com/
http://www.claymath.org/millennium-problems

Blog:
https://thegeekiestone.com/

Solving the Assessment Puzzle — Open Matters

By Sarah Hansen, OCW Educator Project Manager Assessing students’ learning is one of the most important things we do as educators. It’s also one of the most complicated. There’s a lot to consider: When will assessment happen? (Along the way? At the end of the course?) How will we collect useful information about student learning? […]

via Solving the Assessment Puzzle — Open Matters

The Structure of the Earth

Physical Properties of the Earth

The Earth is an oblate spheroid, being slightly flattened at the
poles:

Equatorial radius = 6378 km Polar radius = 6357 km

These measurements are calculated on the assumption that the Earth’s surface is smooth, but this is only an approximation since it disregards mountains and ocean depths. However, the difference between the height of Mount Everest and the depth of the Marianas trench is only about 20 km. Most land is concentrated in seven continents each fringed by shallow seas (flooded continent). Separating these are a number of major oceans including the Pacific, Atlantic and the Indian oceans.

It was Cavendish in 1798 who first calculated the mass of the Earth as 5.977 x 1024kg, and since its volume is known (from 4/3 ∏ r^3 where r is the radius of the Earth), then it can be calculated that the average density is 5.516 g/cm3. However, most rocks exposed at the surface have densities of less than 3g/cc, for example:

sandstone: 1.9 - 2.4 g/cm3
limestone: 1.9 - 2.7 g/cm3
granite: 2.6 - 2.7 g/cm3
basalt: 2.8 - 3.0 g/cm3 

Therefore, a material of greater density must exist at deeper levels within the Earth. The Earth has a series of layers or “shells”, but only the outer few km of the Earth can be directly observed; the upper crust, and the deepest boreholes which reach to only about 12.5 kms. Earthquakes provide the key to the structure at depth.

Earthquakes

Stresses which develop in the Earth may become great enough to break the rocks, and cause slip along the resulting in fractures (faults). Although the slip distance in a given earthquake may be small (cm to metres), the rock masses involved are large and so the energy released is great. The resulting shock waves, or earthquakes, may cause great damage; greatest near the centre or focus, and less further away. The epicentre is the point on the surface of the Earth vertically above the focus.

Detection of seismic waves.
Earthquake energy is transmitted by several types of waves. Two types will be described:

P waves (primary or compressional) are transmitted by vibrations oscillating in the direction of propagation (push/pull).

S waves (secondary or shear), which vibrate at right angles to the direction of propagation. S waves cannot be transmitted through liquids because liquids have no elastic strength.

Recording Earthquakes

The arrival of earthquake waves is recorded by a seismograph. A mass is loosely coupled to the Earth by a spring. A chart is firmly coupled to the Earth. A pen linking them traces the difference in motion between the mass and the Earth’s surface. The arrival of waves from a distant earthquake is recorded as a seismogram on the rotating drum.

Consider what happens to P and S waves as they travel through the Earth.

The most important property of seismic waves is their speed of propagation. The velocity is governed by the physical properties (density, compressibility, rigidity) of the medium through which the wave is travelling.

Earlier in this lecture, it was deduced that the density of the Earth increases with depth. The wave propagation velocity must, therefore, change with depth, and this causes the wave to refract.

Refraction

If a wave travelling through a medium with a fixed density encounters a new medium with a different density, the wave will change its direction. This “bending” of the wave is called refraction.

Data from seismometers located around the world can record waves from any given earthquake. The differences between recordings at different seismometers reveal properties of the sub-surface and hence the internal structure of the Earth.

For example, it has been discovered that the mantle is solid rock, but the outer core is a liquid. This was discovered, because for any given earthquake:-

  1. Both P and S waves are recorded by seismometers at distances of up to 103o from the epicentre.
  2. At distances greater than 103o, no S waves are recorded. This means that S waves that would have reappeared at > 103o have not propagated. The material at depths travelled by such waves must be liquid and be unable to transmit S waves.

Also, it has been discovered that the outer core must have a lower P wave velocity than the mantle. This is because at distances of 103o to 142o, no strong P waves are recorded. The liquid outer core has a lower P wave velocity, causing the P waves to be refracted to a steeper angle, so they cannot re-emerge between 103o to 142o. They actually re-emerge at angles > 186o. There is one small caveat to this observation. The inner core appears to be solid because some weak P wave arrivals occur between 103o to 142o. This is thought to be due to a slight increase in P wave velocity as waves enter the inner core, causing them to be refracted to a shallower angle, to re-emerge between 103o to 142o. If the inner core is solid, S waves could propa- gate there. The graph shows some calculations of what expected S wave velocities would be, but the inner core structure is still a source of controversy.

The MOHO

In the early 20th century a Yugoslavian seismologist by the name of Mohorovicic was studying seismograms from shallow focus earthquakes (< 40 km) that were nearby <800km. He noticed that there were 2 distinct sets of P waves and S waves involved. He interpreted these waves as a direct set and a refracted set. In the refracted set, waves travel down and are refracted at a boundary by a medium of higher velocity.

This boundary separates the crust with VP of 6-7km/sec from the upper mantle where VP starts at 8km/sec. It is called the Mohorovicic discontinuity but is commonly known as the MOHO.

Today, seismologists use artificial explosions to determine the structure beneath the surface and it is from these data that the depth of the MOHO can be calculated and thus the thickness of the crust. The MOHO is at 5-15 km under ocean crust and 35 km beneath normal thickness continental crust. The MOHO can be as much as 70 km deep beneath mountain belts where converging plates have caused an orogeny or mountain building event.

The Structure of the Earth

Recent advances in seismology now allow tomographic images of the interior of the Earth to be produced from P and S wave velocity data. Just as tomographic images of the interior of human bodies are produced by density contrasts in human tissue and bone subject to wave propagation, density contrasts in the Earth can be mapped by combining wave velocity data from large numbers of earthquakes.

The basic idea is that where the solid mantle is relatively hot, the P and S wave velocities should be anomalously low because the heat will result in a density decrease. One should be able to image hot, ascending plumes of mantle asthenosphere by looking for areas of anomalously low seismic velocity. Conversely, where the solid mantle is relatively cool, the P and S wave velocities should be anomalously fast because the lack of heat will result in a relatively high density.

One should be able to image cool, descending slabs of mantle lithosphere by looking for areas of anomalously high seismic velocity. Such images allow us to study subduction zones and constrain how deep the slabs penetrate. It appears that some slabs do not penetrate beneath 670 km whereas others continue down to the core-mantle boundary. This is an area of controversy in geology.

League of Legends Live: A Concert Experience at 2017 Worlds Countdown

League of Legends Live: A Concert Experience at 2017 Worlds Countdown

https://clips.twitch.tv/embed?clip=AverageStormyOilBlargNaut&autoplay=false&tt_medium=clips_embed

 

Astronomy Picture of the Day – Eclipsosaurus Rex

See Explanation.  Clicking on the picture will download
 the highest resolution version available.

Eclipsosaurus Rex 
Image Credit & CopyrightFred Espenak (MrEclipse.com)Explanation: We live in an era where total solar eclipses are possible because at times the apparent size of the Moon can just cover the disk of the Sun. But the Moon is slowly moving away from planet Earth. Its distance is measured to increase about 1.5 inches (3.8 centimeters) per year due to tidal friction. So there will come a time, about 600 million years from now, when the Moon is far enough away that the lunar disk will be too small to ever completely cover the Sun. Then, at best only annular eclipses, a ring of fire surrounding the silhouetted disk of the too small Moon, will be seen from the surface of our fair planet. Of course the Moon was slightly closer and loomed a little larger 100 million years ago. So during the age of the dinosaurs there were more frequent total eclipses of the Sun. In front of the Tate Geological Museum at Casper College in Wyoming, this dinosaur statue posed with a modern total eclipse, though. An automated camera was placed under him to shoot his portrait during the Great American Eclipse of August 21.

 

From: https://apod.nasa.gov/apod/ap171007.html

Astronomy Picture of the Day – Global Aurora at Mars

See Explanation.  Clicking on the picture will download
 the highest resolution version available.Global Aurora at Mars 
Image Credit: MAVENLASP, University of ColoradoNASAExplanation: A strong solar event last month triggered intense global aurora at Mars. Before (left) and during (right) the solar storm, these projections show the sudden increase in ultraviolet emission from martian aurora, more than 25 times brighter than auroral emission previously detected by the orbiting MAVEN spacecraft. With a sunlit crescent toward the right, data from MAVEN’s ultraviolet imaging spectrograph is projected in purple hues on the right side of Mars globes simulated to match the observation dates and times. On Mars, solar storms can result in planet-wide aurora because, unlike Earth, the Red Planet isn’t protected by a strong global magnetic field that can funnel energetic charged particles toward the poles. For all those on the planet’s surface during the solar storm, dangerous radiation levels were double any previously measured by the Curiosity rover. MAVEN is studying whether Mars lost its atmosphere due to its lack of a global magnetic field.

 

Source: https://apod.nasa.gov/apod/ap171006.html

WannaCry a Birthday Gift??

I woke up on the 12th of May, it was my birthday, and I looked on the news feed and saw a burst of articles regarding the WannaCry Ransomware that has swept across the globe.

number20of20symantec20detections20for20wannacry20may201120to2015
In the last few days, a new type of malware called Wannacrypt has done worldwide damage.  It combines the characteristics of ransomware and a worm and has hit a lot of machines around the world from different enterprises or government organizations:

https://www.theregister.co.uk/2017/05/13/wannacrypt_ransomware_worm/

While everyone’s attention related to this attack has been on the vulnerabilities in Microsoft Windows XP, please pay attention to the following:

  • The attack works on all versions of Windows if they haven’t been patched since the March patch release!
  • The malware can only exploit those vulnerabilities it first has to get on the network.  There are reports it is being spread via email phishing or malicious web sites, but these reports remain uncertain.

 

Please take the following actions immediately:

  • Make sure all systems on your network are fully patched, particularly servers.
  • As a precaution, please ask all colleagues at your location to be very careful about opening email attachments and minimise browsing the web while this attack is on-going.

 

The vulnerabilities are fixed by the below security patches from Microsoft which was released in Mar of 2017, please ensure you have patched your systems:

https://technet.microsoft.com/en-us/library/security/ms17-010.aspx

Details of the malware can be found below.  The worm scans port TCP/445 which is the windows SMB services for file sharing:

https://securelist.com/blog/incidents/78351/wannacry-ransomware-used-in-widespread-attacks-all-over-the-world/

Preliminary study shows that our environment is not infected based on all hashes and domain found:

 

URL:

www.iuqerfsodp9ifjaposdfjhgosurijfaewrwergwea.com

MD5 hash:

4fef5e34143e646dbf9907c4374276f5
5bef35496fcbdbe841c82f4d1ab8b7c2
775a0631fb8229b2aa3d7621427085ad
7bf2b57f2a205768755c07f238fb32cc
7f7ccaa16fb15eb1c7399d422f8363e8
8495400f199ac77853c53b5a3f278f3e
84c82835a5d21bbcf75a61706d8ab549
86721e64ffbd69aa6944b9672bcabb6d
8dd63adb68ef053e044a5a2f46e0d2cd
b0ad5902366f860f85b892867e5b1e87
d6114ba5f10ad67a4131ab72531f02da
db349b97c37d22f5ea1d1841e3c89eb4
e372d07207b4da75b3434584cd9f3450
f529f4556a5126bba499c26d67892240

 

Per Symantec, here is a full list of the filetypes that are targeted and encrypted by WannaCry:

  • .123
  • .3dm
  • .3ds
  • .3g2
  • .3gp
  • .602
  • .7z
  • .ARC
  • .PAQ
  • .accdb
  • .aes
  • .ai
  • .asc
  • .asf
  • .asm
  • .asp
  • .avi
  • .backup
  • .bak
  • .bat
  • .bmp
  • .brd
  • .bz2
  • .cgm
  • .class
  • .cmd
  • .cpp
  • .crt
  • .cs
  • .csr
  • .csv
  • .db
  • .dbf
  • .dch
  • .der
  • .dif
  • .dip
  • .djvu
  • .doc
  • .docb
  • .docm
  • .docx
  • .dot
  • .dotm
  • .dotx
  • .dwg
  • .edb
  • .eml
  • .fla
  • .flv
  • .frm
  • .gif
  • .gpg
  • .gz
  • .hwp
  • .ibd
  • .iso
  • .jar
  • .java
  • .jpeg
  • .jpg
  • .js
  • .jsp
  • .key
  • .lay
  • .lay6
  • .ldf
  • .m3u
  • .m4u
  • .max
  • .mdb
  • .mdf
  • .mid
  • .mkv
  • .mml
  • .mov
  • .mp3
  • .mp4
  • .mpeg
  • .mpg
  • .msg
  • .myd
  • .myi
  • .nef
  • .odb
  • .odg
  • .odp
  • .ods
  • .odt
  • .onetoc2
  • .ost
  • .otg
  • .otp
  • .ots
  • .ott
  • .p12
  • .pas
  • .pdf
  • .pem
  • .pfx
  • .php
  • .pl
  • .png
  • .pot
  • .potm
  • .potx
  • .ppam
  • .pps
  • .ppsm
  • .ppsx
  • .ppt
  • .pptm
  • .pptx
  • .ps1
  • .psd
  • .pst
  • .rar
  • .raw
  • .rb
  • .rtf
  • .sch
  • .sh
  • .sldm
  • .sldx
  • .slk
  • .sln
  • .snt
  • .sql
  • .sqlite3
  • .sqlitedb
  • .stc
  • .std
  • .sti
  • .stw
  • .suo
  • .svg
  • .swf
  • .sxc
  • .sxd
  • .sxi
  • .sxm
  • .sxw
  • .tar
  • .tbk
  • .tgz
  • .tif
  • .tiff
  • .txt
  • .uop
  • .uot
  • .vb
  • .vbs
  • .vcd
  • .vdi
  • .vmdk
  • .vmx
  • .vob
  • .vsd
  • .vsdx
  • .wav
  • .wb2
  • .wk1
  • .wks
  • .wma
  • .wmv
  • .xlc
  • .xlm
  • .xls
  • .xlsb
  • .xlsm
  • .xlsx
  • .xlt
  • .xltm
  • .xltx
  • .xlw
  • .zip

As you can see, the ransomware covers nearly any important file type a user might have on his or her computer. It also installs a text file on the user’s desktop with the following ransom note:

2cry

How to prepare for PWK/OSCP, a noob-friendly guide

Few months ago, I didn’t know what Bash was, only heard of SSH tunneling, no practical knowledge. I also didn’t like paying for the PWK lab time without using it, so I went through a number of resources till I felt ready for starting the course.

Warning: Don’t expect to be spoon-fed if you’re doing OSCP, you’ll need to spend a lot of time researching, neither the admins or the other students will give you answers easily.

1. PWK Syllabus
1.1 *nix and Bash
1.2 Basic tools
1.3 Passive Recon
1.4 Active Recon
1.5 Buffer Overflow
1.6 Using public exploits
1.7 File Transfer
1.8 Privilege Escalation
1.9 Client-Side Attacks
1.10 Web Application Attacks
1.11 Password Attacks
1.12 Port Redirection/Tunneling
1.13 Metasploit Framework
1.14 Antivirus Bypassing
2. Wargames
2.1 Over The Wire: Bandit
2.2 Over The Wire: Natas
2.3 Root-me.org
3. Vulnerable VMs

1. PWK Syllabus:

Simply the most important reference in the list, it shows the course modules in a detailed way. Entire preparation I did was based on it. Can be found here.

1.1 *nix and Bash:

You don’t need to use Kali Linux right away, a good alternative is Ubuntu till you get comfortable with Linux.

1. Bash for Beginners: Best Bash reference IMO.
2. Bandit on Over The Wire: Great start for people who aren’t used to using a terminal, aren’t familiar with Bash or other *nix in general. Each challenge gives you hints on which commands you can use, you need to research them.
3.  Explainshell: Does NOT replace man pages, but breaks down commands easily for new comers.

1.2 Basic tools:

You will use these tools a lot. Make sure you understand what they do and how you can utilize them.

Netcat: Most important tool in the entire course. Understand what it does, what options you have, difference between a reverse shell and a bind shell. Experiment a lot with it.
Ncat: Netcat’s mature brother, supports SSL. Part of Nmap.
Wireshark: Network analysis tool, play with it while browsing the internet, connecting to FTP, read/write PCAP files.
TCPdump: Not all machines have that cute GUI, you could be stuck with a terminal.

1.3 Passive Recon:

Read about the following tools/techniques, experiment as much as possible.

1. Google dorks
2. Whois
3. Netcraft
4. Recon-ng: Make sure you check the Usage guide to know how it works.

1.4 Active Recon:

  • Understand what DNS is, how it works, how to perform forward and reverse lookup, what zone transfers are and how to perform them. Great resource here.
  • Nmap: One of the most used tools during the course (if not the most). I’d recommend to start by reading the man pages, understand different scanning techniques and other capabilities it has (scripts, OS detection, Service detection, …)
  • Services enumeration: SMTP, SNMP, SMB, and a lot others. Don’t just enumerate them, understand what they’re used for and how they work.
  • Great list for enumeration and tools.

1.5 Buffer Overflow:

Most fun part in my opinion. There are countless resources on how to get started, I’d recommend Corelan’s series. You probably need the first part only for PWK.

1.6 Using public exploits:

Occasionally, you’ll need to use a public exploit, maybe even modify the shellcode or other parts. Just go to Exploit-db and pick one of the older more reliable exploits (FTP ones for example). The vulnerable version is usually present with the exploit code.

1.7 File Transfer:

Not every machine has netcat installed, you’ll need to find a way around it to upload exploits or other tools you need. Great post on this is here.

1.8 Privilege Escalation:

A never ending topic, there are a lot of techniques, ranging from having an admin password to kernel exploits. Great way to practice this is by using Vulnhub VMs for practice. Check my OSCP-like VMs list here.

Windows:Elevating privileges by exploiting weak folder permissions
Windows: Privilege Escalation Fundamentals
Windows: Windows-Exploit-Suggester
Windows: Privilege Escalation Commands
Linux: Basic Linux Privilege Escalation
Linux: linuxprivchecker.py
Linux: LinEnum
Practical Windows Privilege Escalation
MySQL Root to System Root with UDF

1.9 Client Side Attacks:

Try out the techniques provided in Metasploit Unleashed or an IE client side exploit.

1.10 Web Application Attacks

Another lengthy subject, understand what XSS is, SQL injection, LFI, RFI, directory traversal, how to use a proxy like Burp Suite. Solve as much as you can from Natas on Over The Wire. It has great examples on Code Injection, Session hijacking and other web vulnerabilities.

Key is research till you feel comfortable.

1.11 Password Attacks:

Understand the basics of password attacks, difference between online and offline attacks. How to use Hydra, JTR, Medusa, what rainbow tables are, the list goes on. Excellent post on this topic here.

1.12 Port redirection/tunneling:

Not all machines are directly accessible, some are dual homed, connected to an internal network. You’ll use such techniques a lot in non-public networks. This post did a great job explaining it.

1.13 Metasploit Framework:

Decided to skip this part, but if you still want to study it, check out Metasploit Unleashed course.

 

1.14 Antivirus Bypassing:

Skipped this part too.

2. Wargames

Use them as a prep for vulnerable machines.

2.1 Over The Wire: Bandit

Great start for people who aren’t familiar with Linux or Bash.

2.2 Over The Wire: Natas

Focused on web application, many challenges aren’t required for OSCP, but it helps for sure.

2.3 Root-me.org

Has great challenges on privilege escalation, SQL injection, Javascript obfuscation, password cracking and analyzing PCAP files

3. Vulnerable Machines

Boot-to-root VMs are excellent for pentesting, you import a VM, run it and start enumerating from your attacking machine. Most of them result in getting root access. Check the post on which machines are the closest to OSCP, there is also the https://lab.pentestit.ru/ .

Blog posts regarding my journey through Pentestit.ru.:

Pentestit Lab v10 – Introduction & Setup
Pentestit Lab v10 – The Mail Token
Pentestit Lab v10 – The Site Token