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disk sectors that it had infected, and instead display unmolested data. This redirection, known as “garden-pathing,” where the protagonist is led down a seemingly innocent trail to cover up malfeasance, |
is an early example of some of the more complex techniques employed by modern-day malware (seen often in packers). The first piece of malware to use encryption to scramble its |
contents was the Cascade virus, which first starting showing up in late 1986. The program consisted of a stub encryption/decryption routine (hereby referred to as a decryptor) followed by the |
actual body of the encrypted viral code — a technique that would eventually be adopted by nearly every encrypted malware. Cascade used a simple symmetrical XOR cipher keyed off of |
the size of the file. XOR was a perfect choice at the time because, while it can be a relatively weak cipher (its effectiveness at scrambling data is fully dependent |
on how random the key is that is uses), it was perfect back then for two reasons: - Antivirus at the time, exclusively based on simple pattern matching, had a |
hard time with encrypted viruses. Since the virus body was a random jumble of bytes (encrypted at infection time), the only fingerprint-able pattern was the XOR encryption/decryption routine that preceded |
the actual virus (called a decryptor). The problem here was that AV programs couldn’t distinguish between different strains of the same virus nor could they identify disparate viruses that shared |
the same cryptography routines. Furthermore, as the strings to detect malicious code shrank in size, the false positives would increase as innocent files matching a suspicious byte-string were flagged. - |
Since the XOR operation is symmetrical and reversible, it afforded virus writers the simplicity and brevity of only having a single function to do both encryption and decryption. When every |
byte counts, this is a huge win. As viral science progressed, so did the means to fight back. AV vendors started wising up and were able to match most decryptor |
patterns with a growing legion of decryptor signatures. In order to flourish, the malware authors developed new ways to further obscure their creations. From the Greek oligo meaning abnormally few |
or small. From the Greek morphe meaning shape or form. To combat the weakness in static decryptors, malware authors upped the ante with the creation of oligomorphic malware, which could |
change the decryptor. From one generation to the next, oligomorphic malware would mutate the decryptor used to encrypt and decrypt the malware body. The first example of oligomorphism in malware |
was the bloated file infector virus called Whale, which was first detected in late 1990. It carried with it a few dozen decryptors and would randomly chose one to encrypt |
itself as it spread to a new file. While more complex and numerous, signatures could still be created to detect malware of this type. Other oligomorphic viruses would generate decryptors |
dynamically, making it much harder for the AV vendors to write comprehensive signatures to catch all variations. Historically, it has proven to be infeasible to catch every strain of malware |
as it evolved. Oligomorphic code is indeed a simple version of a polymorphic engine and was portentous of things to come… From the Greek polys meaning many. From the Greek |
morphe meaning shape or form. While statically encrypting and oligomorphic malware were troublesome, they were reasonably containable in terms of how many generational variants the Good Guys had to deal |
with. In 1991, however, the game got more complex. Dr. Alan Solomon is credited with coining the term polymorphism, which is a method of radically changing how malware conceals itself, |
all the while remaining functionally equivalent. This took the malware arms race to the next level. As a polymorphic virus spread from file to file, it would drastically change how |
it encrypted itself. In a properly engineered polymorphic virus, there will be almost no consistency in decryptor bytes from generation to generation. As such, there is no pattern to match, |
no signature to create, and no easy way to find these virulent tricksters. To combat polymorphism, AV vendors had to invent new methods of warfare, including algorithmic-based detection and operating |
system execution emulators (see below). The first polymorphic malware was a virulent .COM infector strain of the Vienna virus written in 1990 by Mark Washburn called 1260 AKA V2PX (this |
would be the first in the Chameleon virus family). The virus was a research project of Washburn’s, who claimed he wrote the code to show the AV vendors that signatures |
alone would not be enough to stop the viral horde. I’m sure they really appreciated that. True to form, as V2PX evolved, its decryptor mutated endlessly. In order to accomplish |
this obfuscation, V2PX would randomly insert so called “junk” instructions into its decryptor. Instructions like clc, nop and unused register manipulations were all part of its sleight of hand subterfuge. |
These low-level assembler mnemonics would change the size and appearance of the code, but not its overall function. The end result was an effective decryptor mutation in every generation of |
the virus that eschewed any sort of pattern matching. The Mutation Engine The first ever polymorphic toolkit, The Mutation Engine (MtE), was released in 1992 by the infamous Dark Avenger |
(it would not be the only one however: DAME, TPE, and many others were released). MtE enabled neophyte virus programmers to link their code to an MtE-generated polymorphic object and |
extend a normal non-obfuscated virus into a highly polymorphic one. At the time, this was a real problem for the white hats. Back then, most AV vendors could not accurately |
detect MtE-laden malware with 100% confidence. As this technique took off, literally hundreds of similar toolkits would be introduced. A polymorphic viral frenzy commenced. Emulation to the Rescue To combat |
the threat of polymorphic malware, AV vendors started including emulation code in their scanners to sandbox untrusted programs. The altruistic hope here is that the scanner would be able to |
execute the suspect program in a walled-off environment where, if it were malicious software, it could do no harm to the file system. During execution, the scanner would check the |
program’s memory image against its signature database in addition to fledging heuristic analyses, which included flagging suspicious behavior such as attempts to modify other executables or writes to the hard |
disk boot sector. The problem with emulation wasn’t just that its algorithmics were prone to false positives (this has improved greatly as it’s matured), it was also vulnerable to armoring |
(AKA anti-anti-virus), where the malware would take measures to prevent the emulator from unraveling its mysteries. Many techniques were employed, and a few notables are listed below: - “Endless” Looping: |
To remain thrift, early scanners would only execute the first few instructions of each program when looking for suspicious behavior; to combat this, virus authors would add huge do-nothing loops |
in the beginning of their code to tie up scanners until they had to move on to the next file. - FPU Usage: Also a time/space trade-off, second-order effect was |
that floating point operations were deemed too expensive at the time and emulators did not support them and would exit. - Fringe Features: Any undocumented or non-standard processor features were |
usually unsupported, such as manual interrupt invoking or register manipulation. As personal computers grew in power, scanners grew in complexity. Eventually, the AV vendors were able to deal with most |
of the pitfalls of emulation and were knocking out most polymorphic viruses, some before signatures were even developed. This forced the virus authors to press the arms race to an |
Large impacts are fascinating. There’s the thriller-movie aspect of them, of course, spiced with enough reality to make them legitimately scary. But the physics of them is equally enthralling, and complex enough that it will be a rich field for |
scientists to study for years to come. The good news for both these aspects is our Moon. Seriously! There are enough craters there for anyone to be happy studying them, and since the Moon is a giant lifeless chunk of |
rock, impacts there seem less urgently threatening. I want to show you two craters on the Moon that are very different, and therefore very interesting. First up, Copernicus. Or more accurately, a small part of this 90+ km (55 mile) |
wide impact feature: its central peaks. [Click to enselenate.] This image was taken by NASA’s wonderful Lunar Reconnassance Orbiter. Copernicus is a big crater, and easy to spot even with binoculars since it sits in a vast lava plain; the |
surrounding material is darkish grey, while the crater is far brighter. It’s also surrounded by a gorgeous system of rays: linear streaks caused by the collapsed plumes of material after the asteroid or comet smacked into the Moon to form |
the crater itself. Copernicus has a series of mountains in its center, the tallest over a kilometer high. These weren’t created in tectonic events like on Earth, though! Giant impacts that cause big craters have weird physics. The pressure upon |
impact can be so high that the rock in the surface flows like a liquid. It splashes outward, then flows back in, surging upwards in the middle of the impact point. This video showing water dropping into various surfaces might |
help: [Click to enlunenate.] It’s very different from Copernicus. The floor is flat, and noticeably lacking in a central peak! Why not? Most likely it’s just size. The impactor wasn’t big enough to create the same conditions as in Copernicus |
(or again Tycho), so the crater shape and structure is different. In fact, you can see places where the crater wall has collapsed inward a bit, like in the upper right (a really nice shot of this part of the |
crater just went up on the LRO site too). The slumped material forms a flat bench halfway down the wall. That sort of feature is common on Earth too, where sometimes mountains or canyon walls subside a bit and form |
those benches. There are lots of other interesting things going on in this crater, and the LRO site has more on those. When I use my own telescope to look at the Moon, I love sweeping over the many craters, |
admiring their natural beauty as well as comparing and contrasting them. You might think the Moon is homogeneous, with craters all looking the same, but clearly the moon is deserving of a deeper investigation than that. Oh, one more thing. |
I said earlier that looking at craters on the Moon makes the threat of impact seem less urgent. After having written all this, I may change my mind a bit. What happens on the Moon doesn’t really stay on the |
Moon: the Earth is bigger, has more gravity, and makes for a nice juicy target. Studying craters on the Moon is important. Besides just helping us understanding the physics and geology of these colossal events, it helps us understand how |
better to prevent them here on Earth; the more we know about impacts, the better! And these craters are, after all, a reminder that big rocks are out there, and they do sometimes find a big blue planet in their |
Archaean bacterium Credit: Corbis In talking to ARPAe chief Arun Majumdar last week, I asked him about the future of transportation fuels. Even with more hybrids and electric vehicles on the road, the U.S. Energy Information Administration says the American driver will rely on liquid fuels for the next 20 years. Corn-based ethanol needs big subsidies and is of dubious |
environmental benefit. So to break the stranglehold of foreign oil, scientists and engineers are developing something called electro-fuels. The alternative fuel comes from running a charge of electricity through a solution containing strange microorganisms that feed on harmful ammonia or hydrogen sulfides. The charge induces to the organisms to convert carbon dioxide into the same kind of fuels we use |
to run our cars. SCIENCE CHANNEL VIDEO: Future Transportation. Trains are getting faster. Cars are becoming more energy efficient. Planes are becoming more dependent on machines to fly. At this rate, future transportation suddenly seems closer than ever. These bugs make the conversion without petroleum, biomass or sunlight –- all in an enclosed cell. The DOE is funding 15 labs |
across the country to find the best electro-fuel solution, and of course at a reasonable cost. Vice President Biden recently gave a nod to Boulder, Colo.-based OPX Biotechnologies, which claims it will produce its first renewable chemical product, BioAcrylic, at lower cost than petro-acrylic with a 75 percent reduction in greenhouse gas emissions. The company's second product is diesel fuel |
bio-processed from carbon dioxide and hydrogen, according to its website. A team at North Carolina State University is combining enzymes from one microbe that grows at 75 degrees Celsius (167 F) with a second one that feeds off hydrogen. This genetic marriage produces precursors to biofuels like ethanol and butanol. Majumdar told me only biofuels capture 1 percent of the |
energy from sunlight, while these new electro-fuels are approaching 100 percent efficiency. The DOE has been under the gun with a Congressional and Federal investigation into the failure of solar tech Solyndra, as well as planned budget cuts to the very research program that Majumdar is so ecstatic about. It would be too bad if promising research -- even high-risk |
Iconic tenor Enrico Caruso was born on February 25, 1873 in Naples, Italy. Over a career spanning 25 years, he performed at the world’s great opera houses, including nearly 900 appearances at New York’s Metropolitan Opera alone. In this age |
of the mp3 we take recorded music for granted, but Caruso was one of the first classical performers to make recordings, 176 examples of which can be heard on the National Jukebox. Caruso died in 1921 at the young age |
of 48 . Celebrate his birthday with Albert Piantadosi’s tribute, “Goodbye Mister Caruso.” Browse the many photos of Caruso in the Prints and Photographs Online Catalog. Finally, serenade your sweetie with a lip-sync to Caruso’s passionate rendition of Friedrich von |
Psoriasis Chronic Inflammatory Skin Disease is a skin disease very frequent, of unknown cause and common people in the same family. Not is a contagious disease, and may be so |
mild that the patient does not know who has the disease. In other cases it may be very severe and affect large parts of the body - in these cases |
is need calm and patient so that treatment is successful. Psoriasis is an ancient disease very common. It affects almost 3% of the population, both men and women. Usually appears |
in the second decade of life. When children under 15 years are affected because it is probably some of the relatives had the disease The disease is characterized by the |
appearance of patches or plaques red body with intense scaling. The main areas manifesting the disease are: knees, elbows, scalp and back. Psoriasis inflames the skin, which is very red |
and looks ranked as scales. It is a chronic inflammatory skin disease that manifests itself in most times, erythematous lesions pink or red covered with scales whitish. In some cases, |
the lesions may be located only in elbows, knees or scalp. Already in others, the lesions spread through the whole skin. Often there is involvement of the nails. Although little |
frequent, there are cases where the joints may also be affected causing psoriatic arthritis. Psoriasis causes great impact on quality of life of patients who often feel rejected or discriminated |
against in their social and working The reasons that cause psoriasis are not yet fully understood. The scientific researches show that there is someone in the family with the same |
problem in 30% of cases. Some factors may increase or trigger disease, such as emotional stress, trauma or skin irritation, infection in throat, low humidity or certain medicines. Psoriasis vulgarize |
or plaque: Plaque psoriasis, vulgar or nummular is the most common. The disease may differ regarding the intensity and evolution. The areas most affected are the elbows, knees, scalp, lumbosacral |
area and umbilicus. Psoriasis in nails: Psoriasis can involve the fingernails, corresponding to a stigma of the disease, because it interferes in social and work activities. One of the hallmarks |
of the disease is the detachment of the nail. To minimize the need to avoid patient trauma. It is therefore important to keep the nail short, dry and clean to |
reduce the odds of stimuli that can enhance A small portion of the patient population may exhibit this kind of manifestation of the disease, which can produce inflammation in joints |
and cartilage, developing pain, difficulty in movements and changes in the way of the joints. Besides the main types of psoriasis, also highlight: * Psoriasis guttata * Erythrodermic psoriasis * |
Pustular Psoriasis * Inverse psoriasis * Palmoplantar Psoriasis Psoriasis is a disease that can be controlled and is not contagious. Stress and anxiety are factors that trigger or aggravate psoriasis, |
Sarah-Jane Stratford on the layered, complex history of Richard III. On September 12, 2012, a skeleton was found buried beneath a Leicester car park, where a church once stood. The |
historical record shows that the bones might be those of the long-lost Richard III, the last Plantagenet king of England and one of history’s most spine-chilling villains. Plenty of people |
are quick to avow that the hump-backed, cold-blooded Richard III lied, connived, and murdered his way to the throne. He had no compunction about murdering his brother, seducing the widow |
of a man he’d just killed solely to marry her for political gain and “not keep her long,” and, just for good measure, imprisoning and ordering the deaths of his |
two young nephews—the rightful heirs to the throne. There’s just one problem with this story. It is not history; it’s Shakespeare. The play Richard III was written in approximately 1591, |
more than 100 years since the king’s death at the Battle of Bosworth in 1485. Shakespeare was greatly influenced by the salacious history written by Sir Thomas More in the |
shaping of his vision of Richard, and the resultant work is one of the most spellbinding dramas in Western theater. The play’s power, however, stretches far beyond its entertainment value, |
and its provocations upon the nature of tyranny and corruption. The fiction the play weaves is so compelling, it has long since eclipsed the reality of history. We believe the |
thrilling lies and have no interest in the more complex, mundane truth. Furthermore, as a culture, we relish a strong villain. We also aren’t keen on gray areas. One reason |
the layered, complex history of Richard’s life was so readily buried is because the alternative created a more gripping narrative. The alternate history was written for purely political reasons. It |
is little more than naked propaganda, burying the truth along with Richard for political expediency. Henry Tudor had won the battle and the crown, but there were plenty who didn’t |
think he had a legitimate claim to rule. Those who might side with the Plantagenets quickly found there was a disincentive to deny the story being spun about Richard—keeping their |
counsel guaranteed they kept their property . . . and heads. As the story became accepted and enjoyed for its Gothic horror, it retained its veneer of truth not just |
because Thomas More is sainted and Richard III is classed as a history, but because it’s more comfortable to dwell in the certainty of what we know. The determination to |
maintain an opinion, despite evidence that contradicts it, has a psychological categorization: “reaction belief perseverance.” It’s the same phenomenon that keeps some people convinced Barack Obama is a Muslim socialist |
born in Kenya. The political impetus that turned Richard III into a Machiavellian monster continues to define much of our modern body politic. In fact, with the growing entrenchment of |
political polarization, we are less disposed toward nuanced Enlightenment thinking and action, and more stereotypically medieval. We have no patience for nuance—we want action, we want drama, and we want |
clearly defined heroes and villains. It almost doesn’t matter what side of the political spectrum we belong to, or our level of education. When it comes to matters of public |
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