Slashdot Mirror
AT&T Identifies Widespread Security Hole - In Locks
__roo writes "The New York Times has an article [free registration required] about a researcher at AT&T Labs Research who has discovered a little-known vulnerability in many locks that lets a person create a copy of the master key for an entire building by starting with any key from that building, and it requires little more than a file and a few key blanks."
so now Master is going to have to release patches and hotfixes?
"Hey steve, check out my new lock!"
"pffft, is it v.3.21.7?"
"no"
"that's like an invite for key kiddies and 1337 crackers"
For those that don't want to register, here's the full text:
Master Key Copying Revealed
By JOHN SCHWARTZ
A security researcher has revealed a little-known vulnerability in many locks that lets a person create a copy of the master key for an entire building by starting with any key from that building.
The researcher, Matt Blaze of AT&T Labs-Research, found the vulnerability by applying his area of expertise -- the security flaws that allow hackers to break into computer networks -- to the real-world locks and keys that have been used for more than a century in office buildings, college campuses and some residential complexes.
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The attack described by Mr. Blaze, which is known by some locksmiths, leaves no evidence of tampering. It can be used without resorting to removing the lock and taking it apart or other suspicious behavior that can give away ordinary lock pickers.
All that is needed, Mr. Blaze wrote, is access to a key and to the lock that it opens, as well as a small number of uncut key blanks and a tool to cut them to the proper shape. No special skills or tools are required; key-cutting machines costing hundreds of dollars apiece make the task easier, but the same results can be achieved with a simple metal file.
After testing the technique repeatedly against the hardware from major lock companies, Mr. Blaze wrote, "it required only a few minutes to carry out, even when using a file to cut the keys."
AT&T decided that the risk of abuse of the information was great, so it has taken the unusual step of posting an alert to law enforcement agencies nationwide. The alert describes the technique and the possible defenses against it, though the company warns that no simple solution exists.
The paper, which Mr. Blaze has submitted for publication in a computer security journal, has troubled security experts who have seen it. Marc Weber Tobias, a locks expert who works as a security consultant to law enforcement agencies, said he was rewriting his police guide to locks and lock-picking because of the paper. He said the technique could open doors worldwide for criminals and terrorists. "I view the problem as pretty serious," he said, adding that the technique was so simple, "an idiot could do it."
The technique is not news to locksmiths, said Lloyd Seliber, the head instructor of master-key classes for Schlage, a lock company that is part of Ingersoll-Rand. He said he even taught the technique, which he calls decoding, in his training program for locksmiths.
"This has been true for 150 years," Mr. Seliber said.
Variations on the decoding technique have also been mentioned in passing in locksmith trade journals, but usually as a way for locksmiths to replace a lost master key and not as a security risk.
When told that Mr. Seliber taught the technique to his students, Mr. Tobias said: "He may teach it, but it's new in the security industry. Security managers don't know about it."
In the paper, Mr. Blaze applies the principles of cryptanalysis, ordinarily used to break secret codes, to the analysis of mechanical lock designs. He describes a logical, deductive approach to learning the shape of a master key by building on clues provided by the key in hand -- an approach that cryptanalysts call an oracle attack. The technique narrows the number of tries that would be necessary to discover a master-key configuration to only dozens of attempts, not the thousands of blind tries that would otherwise be necessary.
The research paper might seem an odd choice of topics for a computer scientist, but Mr. Blaze noted that in his role as a security researcher for AT&T Labs, he examined issues that went to the heart of business security wherever they arose, whether in the digital world or the world of steel and brass.
Since publishing Mr. Blaze's technique could lead to an increase in thefts and other crimes, it presented an ethical quandary for him and for AT&T Labs -- the kind of quandary that must also be confronted whenever new security holes are discovered in computing.
"There's no way to warn the good guys without also alerting the bad guys," Mr. Blaze said. "If there were, then it would be much simpler -- we would just tell the good guys."
Publishing a paper about vulnerable locks, however, presented greater challenges than a paper on computer flaws.
The Internet makes getting the word out to those who manage computer networks easy, and fixing a computer vulnerability is often as simple as downloading a software patch. Getting word out to the larger, more amorphous world of security officers and locksmiths is a more daunting task, and for the most part, locks must be changed mechanically, one by one.
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But Mr. Blaze said the issue of whether to release information about a serious vulnerability almost inevitably came down to a decision in favor of publication.
"The real problem is there's no way of knowing whether the bad guys know about an attack," he said, so publication "puts the good guys and the bad guys on equal footing."
In this case, the information appears to have made its way already to the computer underground. The AT&T alert to law enforcement officials said that a prepublication version of the paper distributed privately by Mr. Blaze for review last fall had been leaked onto the Internet, though it has not been widely circulated.
"At this point we believe that it is no longer possible to keep the vulnerability secret and that more good than harm would now be done by warning the wider community," the company wrote.
There is evidence that others have chanced upon other versions of the technique over the years. Though it does not appear in resources like "The M.I.T. Guide to Lockpicking," a popular text available on the Internet, Mr. Blaze said, "several of the people I've described this to over the past few months brightened up and said they had come on part of this to make a master key to their college dorm."
Mr. Blaze acknowledged that he was only the first to publish a detailed look at the security flaw and the technique for exploiting it.
"I don't think I'm the first person to discover this attack, but I do think I'm the first person to work out all the details and write it down," he said. "Burglars are interested in committing burglary, not in publishing results or warning people."
Mr. Tobias, the author of "Locks, Safes and Security: An International Police Reference," said that the technique was most likely to be used by an insider -- someone with ready access to a key and a lock. But it could also be used, he said, by an outsider who simply went into a building and borrowed the key to a restroom.
He said he had tested Mr. Blaze's technique the way that he tests many of the techniques described in his book: he gave instructions and materials to a 15-year-old in his South Dakota town to try out. The teenager successfully made a master key.
In the alert, AT&T warned, "Unfortunately, at this time there is no simple or completely effective countermeasure that prevents exploitation of this vulnerability, short of replacing a master-keyed system with a nonmastered one."
The letter added, "Residential facilities and safety-critical or high-value environments are strongly urged to consider whether the risks of master keying outweigh the convenience benefits in light of this new vulnerability."
Other defenses could make it harder to create master keys.
Mr. Blaze said that owners of master-key systems could move to the less popular master-ring system, which allows a master key to operate the tumblers in a way that is not related to the individual keys. But that system has problems of its own, security experts say.
Mr. Blaze suggested that creating a fake master key could also be made more difficult by using locks for which key blanks are difficult to get, though even those blanks can be bought in many hardware stores and through the Internet.
But few institutions want to spend the money for robust security, said Mr. Seliber of Schlage. His company recommends to architects and builders that they take steps like those recommended by Mr. Blaze, measures that make it more difficult to cut extra keys -- like using systems that are protected by patents because their key blanks are somewhat harder to buy, Mr. Seliber said. Even though such measures would add only 1 to 2 percent to the cost of each door, builders were often told to take a cheaper route. He said that they were told, " `We're not worried about ninjas rappelling in from the roof stuff -- take it easy.' "
That is not news to Mr. Blaze, who said it was also a familiar refrain in the world of computer security. "As any computer security person knows," he said, "in a battle between convenience and security, convenience has a way of winning."
How did you post that message then?
"You heard the man, Tubbs.. get undressed."
courtesy of Google News
In the cert advisory, The Microsoft Corporation are quoted "Those who upgrade to Windows XP Service Pack One should be unaffected by this exploit"
I see several problems with the article.
He said the technique could open doors worldwide for criminals and terrorists.
All in all, the article sounds more like fearmongering than a real concern.
Lock picking kits and expliots have been avalible for a very long time, out of the back of magazines (soldier of fortune, most notably) and there have even been text files about it. Why does it take a computer security expert to make us nerds consider "real life" attacks a possibility?
"You sir, have just crossed my happy line..."
There is an old proverb in *.ee
Locks are against wildlife. Humans will have no problems with them.
"...a little-known vulnerability in many locks..."
Yeah, until now.
Talisman
"Study your math, kids. Key to the universe." -The Archangel Gabriel
I find it interesting seeing that security by obfuscation is a prevalent concept throughout mankinds realm. I guess it is nurtured by the ostrich-sticking-head-in-sand effect of thinking something doesn't exist if we're not aware of it.
It also makes me laugh how newspapers always skew stuff for sensationalism: now terrorists are one step closer to the US. They are pounding on the gates! WATCH OUT!!!. I think this security whole is mostly going to be used by 16 year old K-Mart workers.
Anyways, very nice article in the end, and hats off to AT&T for having 'brass hats'.
-S
--- What parts of "shall make no law", "shall not be infringed", and "shall not be violated" don't you understand?
Any system that has a "master key" to allow access - be it a physical lock on a door, a backdoor to a program, a key-escrow system, whatever, allows this kind of attack - get the master key, game over.
I had do design an encryption system to manage software options in a piece of gear I designed. I thought about having a "back-door" to enable options on any unit, the better to test software. I quickly abandoned that idea - let the master key get out, and it's game over. Sure, it may make my life slightly more difficult as a developer, but it also means that no one, not even me, can cheat the system.
When I had to write the system up for export permission, I described it in detail - algorithm, file formats, I even had to include the source code for the relevant sections. I suppose you could get that information with a FOIA request. Knock yourself out - if you don't have the private key of the keypair, you won't be able to create the options file.
Say it with me, kids - "master keys and back doors are BAD - JUST SAY NO!"
www.eFax.com are spammers
This is hilarious.
I mean, anyone can break a window and jump right in!!
We can call that a "backdoor", and the plywood to cover them "patches".
The funny thing is, the lock system was not designed to have a single master key. Instead, there was supposed to be a different master key for each building. The campus wide master key was an "emergent property" of the similarities between the various building master keys. Only students possessed this master key :-)
I still have the key, but it's not so useful any more, as they've changed many of the locks.
Doug Moen
I have written a truly remarkable program which this sig is too small to contain.
Xerox PARC have issued an advisory stating that any combination lock can be "cracked" by a malicious terrorist with a finger. Due to the digital [sigh...] nature of this crime, it is now illegal to own a finger under the terms of the DMCA and patriotic Americans are being asked to remove all their fingers in a show of solidarity. U.S. President, George W. Bush, is said to be having some difficulty removing his finger from his arse. £:-)
BTW did the original story remind anyone else of the safe-cracking chapter in "Surely you're joking, Mr. Feynman"?
Does anybody remember the MIT Guide to Lockpicking (PostScript file??) that was readily available on the internet in the past? We downloaded it back in '94 and friend used it to make some lock picks by filing down some nails. Let me tell you, some fun was had on campus with the practical jokes that followed ;)
How different is this from making an ordinary copy of a key
It is different because the method can be used to create a Master Key to an entire building (like every single door in a block of flats for instance) from a key that only opens one single door in the same building.
If you make a copy of the single key, you only get to open the single door.
The obvious problem that allows a lock to be an oracle is that the pins are independent of one another, so a "mixed" key that is partly master key and partly a normal key for that lock will open it. There presumably could exist a technical solution that needs only changes to the locks, and doesn't involve whacked-out Medeco[tm] patented key blanks with slanted cuts (although medeco may very well own related patents that would cover some aspects of the improved lock design). However, that solution would be mechanically somewhat difficult (there's a reason master keys are designed the way they are). Maybe there's a good business opportunity for "medium security" locks, but unless this attack becomes very widespread installations with a high theft risk may just start using electronic locks more. Not that many of those are that great except by significant degrees of obscurity -- I'm wondering how many independent parameters there actually are to this resonant-circuit proximity badge I got issued for access to a machine room...
I think that the manufacturer of the locks should sue AT&T under the DMCA for exposing weaknesses in an access control device. Furthermore, AT&T are terrorists for releasing this sensitive security information to the Net before other sites using the same locks are able to correct the vulnerability. I demand that the perpetrators that discovered the weakness with these locks be sentenced to life in prison. We can't have these hackers running free, finding security holes and disrupting national security!
Why bother.
Am I the only one that wants bluetooth everywhere, including on my door locks, so that I can unlock my door either auto (when my cell phone + my key get close) or by entering a password (user preference)?
Among all the other cool data sync things I think bluetooth enables, the death of keys is the other cool thing I really want bluetooth for.
The ultimate network admin tool needs HELP!
Cryptographer Matt Blaze (of AT&T),previously known for cracking the backdoor of the vaunted 'clipper chip' has submitted a publication to the IEEE journal "Security and Privacy" which demonstates that given an ordinary building key (like your office key or one borrowed for the rest room) you can get 'root' access to the entire building (i.e. a master key) with no more that about 30 guesses and $2.00 at the hardware store, and typically much less than that.
The crack works on virtually all locks and was inpsired by parallels to cryptographic analysis, reducing the search from exponential to linear, and exploiting 'key" generation weaknesses. Virtually all master-key locks are vulnerable.
There is also a story on the front page of the nytimes covering police verification of the threat including giving the instructions to a 15 year old.
Some drink at the fountain of knowledge. Others just gargle.
A Schlage employee, on condition of anonymity, said that they were consulting with their legal team on the feasibility of invoking the DMCA against Matt Blaze and AT&T. "Schlage locks are frequently used as a technological measure to protect copyrighted materials. By trafficking in information which allows the compromise of these locks, Mr. Blaze and AT&T are clearly violating the Digital Millenium Copyright Act."
Stop-Prism.org: Opt Out of Surveillance
The technique is very simple. Mr Blaze has only succeeded in reinventing the wheel. I discovered this on my own almost 40 years ago in high school.
All you need is a file, some key blanks, calipers or modified micrometers, a soldering iron, some solder, and a working key to any lock in the system.
Use the calipers to determine all possible legitimate key cut depths. A typical lock will have 5 or 6 tumbler columns. Each column will usually have 10 or fewer possible key cut depths. The range of legitimate depths can be determined by examining several keys from the same system with the calipers.
Make a few copies of the working key to modify. You don't want to mess up the original. Work with one tumbler column at a time. The idea is to change the key cut depth and find another cut depth that opens the lock. I used an old Weller soldering gun and some solder to build up the key cut to it's highest value (minimum cut depth). Start filing and test each possible cut depth for another value that works. Frequently more than one can be found. This is common in sub-mastered systems. Record the working values and repeat the process for each tumbler column.
The master cuts will usually not share the same cut depth as the working key. When you've determined all of the master cut values, file yourself a master key using the new found working values.
Ok, there are a lot of replies here that seem to be saying that physical security, especially regarding locks, is not that important. You would be surprised.
Let's look at places that have master keyed systems:
So, it shouldn't be taken lightly that many master key systems are vulnerable to attack.
You can talk about your electronic lock systems all day, but most (at least in the UK) have a normal lock as part of them, with the electronic system for convenience and being able to tell who is where and when. If they don't have a normal lock in them, then they quite often have fire crash bars on the other side.
I haven't had a chance to read the paper yet, as the crypto.com site is slashdotted, as is the mirror I found. However, a lot of master key systems have vulnerabilities. For example:
Some keys have ridges down the sides. Sub master keys only differ from master keys in that they have these ridges, preventing them from being used in other parts of the building. File off the the ridges, and off you go.
Get two or more keys from a mastered building. Notice similarities and differences. It is often very easy to deduce the master key from this, because often the mastering works by pins having several splits in them.
These are extremely simple ways of finding masters. There is of course the fact that keys are often badly controlled, and unlike passwords, are not easy to change from a central location.
Security through obscurity is often a method used with locks. And it works reasonably well. I would say that lock picking is a far rarer skill than being able to use a computer well.
Some of the more recent lock systems (Assa, Schlage etc.) are very hard to copy, sometimes involving three separate mechanisms in the lock which all need to work. This is if you can obtain blanks. Some even involve small magnets. They are hard, if not impossible to pick as well.
More worrying, however, is the lack of physical strength in most doors. If you aren't afraid of leaving traces, opening most doors by force is remarkably easy. Yale locks (front door latches) often only take one kick to open. Even mortice locks are often badly installed and not that strong. Even if the lock holds up, the door, most of the time, won't hold up to a crowbar, or in desperate situations, an electric saw of any kind.
So, although I am sure that the technique presented in the paper has been around for years, it's going public big time now. We're going to have to welcome the script kiddies who practise on the real world soon.
No. Installing master wafers costs money, so it's only done when you actually want to have a master key.
It's done by installing master wafers into the lock. A normal cylinder lock has pairs of pins, touching each other with a spring pushing them into the hole where you put the key. When you put the key in, the pins all line up, and the cylinder can turn, opening the lock. The length of each pin varies, in the same pattern that you see on the key. By putting in master waters you instead have 3 pins, meaning that each set has two possible positions, and therefore two different keys work in the same lock. By making the second key the same in every lock, you have a master key. The master key for each building or complex would be different, so there is no universal master key.
Adding master wafers increases the cost of the lock, so it's only done when the lock is going to be used in a master key situation.
Here's the method in a nutshell.
1) get a normal key that opens a lock.
2)count the notches, if its a 5 pin tumbler, then buy 6 more blank keys. ($2.00)
3) cut 5 keys to be identical to the original except at one of the pin position, let it be full height. SO that you now have 5 keys each with a full height blank at a different pin postion.
3.b) reducing the complexity. it's not physically possible to have a full height position adjacent to a deeply cut position. No problem, just cut it as high a possible, the master key suffers the same limits too, and this reduces the complexity of the pattern.
4) insert the first key. does it turn? No then file off 0.010" of metal and try again. within 7 tries, usually only one or 2 it will turn. congatulation you now know the pin 1 master height.(duh: ignore the turning at the original height.)
5) insert key2, rinse, lather repeat.
the beauty of this crack twofold. first, you are discovering the master heights of each pin independently, so the combinatorics is just linear in the number of resolvable pin heights not the product of pin-positions times pin heights. Second, you are also simultaneously factoring the ordinary key out of the master key combination, thus only discovering the master key not some useless key that is part paster and part ordinary key (that would only owrk on that particular lock).
6) Exception: if you cannot find the a pin height that opens one of the tumblers (ignoring the obvious one for the original key) then the original key height is the one for the master too.
Some drink at the fountain of knowledge. Others just gargle.
Everybody knows that. It's the way master-keys systems works, you take of pieces until you have the most generic key, the most generic keys needs inherently to be the smallest and thus the least safe.
Not that it can't be news and research for security people, but I can't see how this can "make it easier for buglers and terrorists", anyone in the business or anyone thinking about it for a few minutes knows thats how it works and have always worked, and how it has to work if you really wants a master key system.
Longer keylength...
When I replaced the locks on my house, the lock company advertised a series of locks with a restricted keyway, which meant according to the locksmith that their company was the only one in the region where you could get key blanks, cyliners or other hardware associated with this series of locks.
I ran into this phenomenon in college; I tried to make a copy of my girlfriend's dorm room key at several hardware stores. I actually milled off and polished the head of the key where the "DO NOT COPY" and "UNIVERISTY AABBCC" info was on it so it looked like an ordinary key.
The last place I went to the guy looked at me and laughed and said, "Nice job, but its a university key -- the blanks and hardware are sold directly by to the University key shop. Even if I wanted to, I couldn't make a copy of it, I have no blanks that will work."
Anyway, the technique described here requires a bunch of blank keys, which if you can't get or are extremely hard to get makes you wonder if this technique would work in places that employ limited keyway hardware.
No need to "Free Kevin" anymore... he's got the master key!
"No, Officer, I didn't steal the key to the prison, I didn't take any hostages, all I had to do to get out was use this file here that Randall sent me in a Perl 6.0 Birthday Cake..."
this is absolutely hilarious because of the fact that this so plainy illustrates the hypocrisy inherent in the DMCA.
if this guy were publishing a similar article about virtual locks in operating systems, he would be in JAIL already, awaiting trial and facing billions of dollars of charges against him.
gotta love it
A year spent in artificial intelligence is enough to make one believe in God.
The so-called "little known" faults with locks have been around since the little things have been invented. There are books on how to circumvent locks.
For centuries, locksmithing has been a sort of "black art" and the inner workings of them kept under tight control. But that only goes so far, as we all know from the Crypto industry.
Locks are, in fact, absurdly easy to open if you know what you're doing. If you've got one key to a lock that is master keyed, you can easily figure out what the master key looks like. Without that initial key, it's only slightly more problematic.
And don't think safes are any safer. Except for those that are specifically designed to thwart attack, most safes are designed to protect documents from fire and environmental hazards. They are not designed to keep intruders out. For those types of safes, anybody with a heavy hammer and a metal punch can open it. You'd be surprised how many people are stupid enough to put cash and valuables in them. In high schools, the combination padlocks on school lockers can easily be opened with a screw driver.
As the old saying goes, locks are meant to prevent honest people from being tempted. The crooks don't care.
I studied locks in depth when I was in high school and put that knowledge to good use when I needed quick cash as a starving student in university.
Needless to say, I'm posting this anonymously.
How about having a double-sided lock, where the regular keys move tumblers on the top, but the master key moves tumblers on the bottom - and rigging it so either set of tumblers can release the lock?
Then the unique keys need not have any relation to the master key at all, thus returning the security level of these devices back to where most people thought it already was.
-Baron YamConsidering I recently bought a house in one of those "cookie-cutter neighborhoods", here's my experience:
The locks come with a "contractor key" and a "Owner key". Until the Owner key is used in the locks, the contractor key will open it. Once the Owner key is used, it breaks one (or more?) of the pins the contractor key uses to open it, rendering the "master" unusable.
Of course, I have added more locks since then, so it's not as big a deal if this didn't work...
I am dyslexia of borg - your ass will be laminated.
Well as en evil overlord you should know that it's always preferable to get the key to the restroom, make a master key, and then copy the plans of the good guys without them ever knowing
You break down the door and steal the plans: they change the plans and install stronger door. That's a vicious circle
You make a master key and steal their plan, they know nothing, plan stays the same, locks stays the same. You screw their plan over without letting on you know it, then next week when they have a new plan you go get that too.
pff evil overlords these days, no respect for finesse. You should be EvlUndrLrd instead
And no Occams razor doesn't apply, "Out of two possible explanations the simplest one is most likely to be true". You seem to be thinking along the lines of "Out of two methods of breaking and entering, the simplest one has to be better" which may not be true depending on the situation
Compare the time it takes to make a master key and enter 100 rooms to the time to break down 100 doors
- We are the slashdot. Resistance is futile. Prepare to be moderated -
This is not an unknown technique. I did this 30 years ago in college. And I only made adaptations to the technique described in a book on locksmithing which was checked out of the college library. I just didn't have any blanks to work with so I made do with one lost key I found. The campus used a type of blank not sold to the public.
A grand master keying system is based on 5 to 8, but usually 6, tumblers, with typically 10 levels or codes for each tumbler. A simple master system will have at least 2 tumbers with double cuts (but the doubles cannot be cut too close). A more complex system with a level of submastering will have 4 tumblers double cut. A grand master system with potentially two or more levels of submastering will have all the tumblers double cut.
Presuming it is a grand master system (and very large numbers of change keys generally are made this way even if no grand master key is produced), then you can presume that each position on the key is different between your key and the grand master. And not only is it different, but you can also rule out the level which is one above or below what your key has (the tumbler piece would be prone to pivot and jam, instead of slide, if cut too close). And even two levels apart is often avoided because a tumbler piece of those length can jam, although they insert a ball if the tumbler width is the same as 2 levels in that position (or 3 in some systems).
So for a typical 6 tumbler 10 level system, you can rule out 3 levels (or 2 if your key is at the highest or lowest) at each position, and the levels 2 above and below are less likely (try them last).
From your key, you can figure out about where all the levels are. Any additional keys (and I had one, and since this is a non-destructive step, I could also look at a friends' keys) can help. Now with the one spare key I had (extras help a little), you begin the step to find the master levels.
When a key position is ground just a little bit too high, usually about 1/4 of a level interval, it can still engage the tumbler cuts, but it will be rough when doing so. The same thing happens when it's low, but that's not helpful, so make the cut a little high. Even if the other positions are wrong this can be done, but if they are right it's easier. Putting a bit of solder on the position to raise it really helps because now you can see an indentation formed due to the pressure. Attempting to turn the key in the lock will try to work in those positions just a bit off, but will leave a mark on the key, especially if the metal is soft like solder. If there is no indent, you didn't get the right level, so try another at that position.
Repeat for all positions. If you are good you can even work all positions in parallel and accomplish this in just minutes. Once you have a level for every position which is at a different height than your own key, you probably have the grand master. If your key was really a submaster, this could trip you up. But they generally try to avoid giving out submaster keys to students.
There are two other ways to do this.
You can remove the lock and pull the tumblers and measure them. Be very careful because when you tap out the slide to expose the tumblers, do so one at a time because there's always a spring on top to keep the tumblers under pressure. Of course don't lose the parts, and don't lose the order the tumbler pieces come out. Now you can simply see what levels for each position make up the grand master.
Another method is to figure out all the levels and their distances. The micrometer caliper helps here. Write down the levels for your key. The next step is to examine other keys of other students. Of course they will think you're trying to make a copy of their key, but if they're your friends and you can trust them, you can reveal your real plan. Write down the levels for their key as well. This now lets you rule out some more levels at each position which the master cannot be. With enough keys you can narrow down just what the grand master key is.
If all the keys you examine are part of the same submaster system, you'll notice that 2 or 3 or maybe 4 positions are just the same on all keys. The grand master will be different there, but if you just cut your new master key at those levels anyway, while you won't have a grand master, you will end up with a submaster which can be used on all the locks in area (usually a building or so) that the examined keys came from.
A combination of having a few change keys (yours and a few friends' keys) to rule out more levels in some positions, and working with the first method to find the master levels, can speed things up for you.
Like I said before, I didn't actually invent these methods; I read them from a locksmithing book. I merely adapted the solder techniques to make things a little easier. Real locksmiths can do it without solder.
now we need to go OSS in diesel cars
And now for the secure solution. You're gonna like this (in German).
now we need to go OSS in diesel cars
... this is the vaunted back door or front door exploit ... side doors too.
Infuriate left and right
There's another aspect to this article besides the lock-hacking technique.
The writer speaks of the familiar dilemma of whether to publish to the "Good Guys," which notifies the "Bad Guys" simultaneously, or keep the information secret, knowing the "Bad Guys" could be sharing it already. Same old story we know from cyber security.
Then there's the "Locksmith" angle, "We've been teaching our students this for years, nothing new here." One wonders how the teachers sorted the trustworthy students from the evil students.
Good guys, bad guys, locksmiths, students, trustworthy, evil.
The enormous elephant here is whether people and their motives can be categorized this way. The truth is, these categories aren't cut and dried distinctions.
Take your government agent, for instance. When we're thinking about wiretapping mad bombers, they look more like good guys. When we're thinking about wiretapping political dissidents, they're bad guys. Same people, same behaviors, different categories.
Even discussing the distinction brings up more fuzzy categories: "bombers," "dissidents," "we."
As long as security is addressed from a good-guys vs bad-guys distinction, the argument will go in circles, because you can't really sort out the good guys from the bad guys without a clear value context. If you're diligent, you'll get mired in the values debate, and if you're not, you'll end up drawing biased conclusions.
The best stragegy in the good guys vs. bad guys debate is not to play the game.
When making powerful tools like locks, master keys, and cryptography, you have to bite the bullet that you can't really manage the motives of the tool users.
Oh, one more thing. If you do decide to make yourself a grand master key, and are tempted to carry it around on your key ring, cut the hilt off so that the key will go in too far to work. Then only you will know that you have to put it in only part way. So if you get stopped and someone thinks you might have a master key and tries the keys on your ring, their natural human thing of "go all the way" will prevent them from detecting that your key works the lock.
now we need to go OSS in diesel cars
Bruce
Bruce Perens.
For one thing, building up solder in each position makes it a lot easier to see the indentations. But the real reason this works is that if you apply a back and forth motion as your attempt to turn the key, the indentations can be made even if the other positions are not cut properly at all. So this can be done with one key, and it doesn't even have to be a blank (but it does get modified in the process, so if you can get a blank, that's better).
now we need to go OSS in diesel cars
Just offhand:
(1) cut 6 identical keys to the original
(2) In one slot, cut as far down as possible, and drill a hole in that location, where you can put a mobile pin on a spring and a wire.
(3) drill a hole along the base, as well, and run the wire through.
(4) Now pull on the wire to find the alternate height. No filing required [prework necessary].
Just write down the numbers you get
(5) Go home and cut new key.
Also: to get around the lack of a blank:playdoh; wax; metal; plaster; small metal casting. Or digital camera; ruler; grinder; piece of small metal.
I don't take much comfort in those workarounds.
At this point, I think that digital locks with varying codes might be a tad more secure. For example, to get the day's code, the admin takes his phone number [or street address, though a random memorized number is best], adds the date to each digit and the time on the lockbox to the last 4 digits, and that's the code. Before he gets up to go in, he figures out what it will be, in his head. Of course, if he forgets entirely, he can take a blowtorch, melt the plexiglass, and let secretary out. Then call in work crews to replace the plexiglass, and stays there, meanwhile, memorizing the *new* number, and keeping an eye out for ninjas rapelling down from the roof.
Or he can write the code on his desk, the front of his pocket protector, or whatever.
Or how about this? Specialized beeper tied to lockbox, on continuous recharge. Beeper takes incoming code, checks it against security code, checks source phone number against President's code -- and authorizes computerized lockbox to open upon access key, within the next 1 minute.
Now, to go in, you pull out your cell phone, call the company president -- he pulls out his video cell phone, calls a video cell phone watching the hall; makes sure that it's you, and then calls the beeper, enters the code [encrypted, of course], and authorizes you to go in.
Of course, I'm not a cryptologist. I'll be a cryptologist could find a dozen ways to break my idea apart. After all, the more complex a system is, the more flaws it has (doesn't it?)
Correct Horse Battery Staple: 72 bits of entropy. Enter "Correct H" into google. When it generates the phrase, that's
The method as described on other comments, is just brilliant.. But there is one problem that nobody has mentioned..
How do you get the blanks ?
You see, with master-key systems the keys have other shapes than ordinary keys (often a mirror pattern if you look at the end of the key, so ordinary keys won't fit in master locks) Keys in master-key systems are often also a little longer than ordinary keys.
And Joe sixpack just can't walk into any hardware store and ask for the blanks.. The hardware store has limited numbers (if any at all) and has to get the paper-certificate that was delivered with the key-system, before they will cut you a new copy.
And, no, just bringing the master key to them and asking for a copy doesn't work (I already tried that ;-)
echo '[q]sa[ln0=aln80~Psnlbx]16isb572CCB9AE9DB03273snlbxq' |dc
1) interchangeable core locks (Falcon or Best types). In addition to having master pins for the master key, there will be additional pins for the alternate shear line for pulling the cylinder out. Basically, if you find another key cut that works, you don't know if you have found the master key or the cylinder removal key cut.
2) MK? GMK? GGMK? Some key systems have multiple levels of keying. Though a well-designed system won't have too many stacked master pins, you still will likely end up finding a cut that works and not knowing if it's for the Master Key, Grand Master Key, Great-Grand Master Key, etc. Depending on the "resolution" of the key system, you could end up with a sub-master that only opens (say) five doors.
3) restricted keyways. Medeco, Assa, Schlage, et. al offer numerous restricted keyways. Good like finding blanks.
4) maximum adjacent cut differential. A Schlage key, for example, can have a depth from 0-9 on any given cut, but no two cuts that differ by more than 7 can be next to each other. If your office key is cut to 99333, and the master key is 51133, then one of the keys you'd have to cut using this system is 91333. A nine and a one are over the max differential, which would either obliterate the "1" cut, or the angle between them would be too steep-- in which case, good luck pulling this key out again.
If a job's not worth doing, it's not worth doing right.
Normal pedestrians cannot get blanks for some key types. The blanks are kept locked away.
In particular: Medico. Their keyways (the pattern of slots on the key's side that admit it to the cylinder) in their high-security models are in a number of (copyrighted) combinations, each sold only to one locksmithing company which is under contract to only resell cut keys, keep records (with ID and passwords) of the buyers, and only sell COPIES to the legitimate owner(s) of the particular lock. The privileged smiths go along with this, too, because Medico tries to get them to violate the contract and will transfer it (along with the lucrative business) to some more picky locksmith if they do.
So unconnected people who want to try such attacks against Medico locks need to make their own blanks. But that's not hard with a model-maker's midget milling machine, of which several brands are available.
(But Medico is also less vulnerable to attacks of the sort described. The lock's pins have a wedge-shaped tip, the cut in the key is at an angle across the axis of the key, and the pin must be rotated by the proper angle as well as lifted to release.)
But most of those "do not duplicate" keys are just ordinary keys from common manufacturers, which have been stamped. The stamp relates to laws prohibiting the copying of such a key and penalizing vendors who get caught doing so.
Of course if someone sticks a label saying something like "garage" or "front door" over the stamp, most hardware store clerks won't notice the stamp and will blithely make as many copies as desired.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
This is totally obvious. Anyone who knows how a master key system works can do this and probably already has. I did it myself in college; it took a copy of my dorm key and a chainsaw sharpening file, both picked up from the hardware store for about $2, and about 90 minutes of fooling around, and I had a master key to the dorm.
The dorm management did discover it eventually. I didn't use it for anything but a little urban exploration, but I think I let a few too many people back into their rooms after their roommates locked them out and the RA wasn't around, and it became common knowledge that I had the key.
They asked how I found out how to make master keys, but didn't seem to be too convinced when I just said "Well, it's obvious, isn't it? Just think for a minute and anyone could figure it out." Probably the wrong thing to say to someone who was probably a humanities major.
My knowledge came exclusively from the Junior Worldbook Encyclopedia entry on how locks work, plus about 2 minutes of thinking about it.
But just wait til they plug the analog hole ;)
~REZ~ #43301. Who'd fake being me anyway?
Okay, I've read the full article [that's what RTFA means, isn't it?], and they say that to defeat priviledge escalation, you have to add to each lock pin a random additional pseudo-master-lock combination. However, they then note that this decreases the security of each individual lock.
What they don't say, but is easily calculated, is that you can raise the security of each individual lock by increasing the number of pins.
Specifically: if you have a single master key, then you have to go up from double-cut up to triple-cut. That means that I'll work with log-base-3 below (for triple cut).
In that case, the number P of additional pins you must add, having formerly had N pins, and having x (let us suppose 9) possible cut heights, then
P = N/[Log3(x)-1]
So if you have 9 possible heights for each pin, single master key, and 5 tumblers, then you can prevent privelege escalation with no further loss in security by going to 5+[5/(2-1)]=10 pins. Not common today, but not impossible. Currently most locks run from 5 pins to 8 pins. Add two pins to an 8 pin lock, and you get your 10 pin security, privilege-protected.
Or you can go open source.
Correct Horse Battery Staple: 72 bits of entropy. Enter "Correct H" into google. When it generates the phrase, that's
This isn't exactly news...
I've known about the flaw in the master key system for a long long time.
Actually, in many circumstances you can get by the mechanism by continually retrying and wiggling your key until the fit hits.
Its not guranteed, but its a little better then using a file.
"You should always go to other people's funerals; otherwise, they won't come to yours." -- Yogi Berra
I brute forced the lock on my dorm room door when I was in college. It took a few tries, but I kicked and kicked until the door broke open.
And specifically read section 9.10 about Master Keys. This stuff is pretty old and well circulated. The entire guide makes for a great read if you're bored. If you're interested in mind teasers, puzzles, and such, you'll appreciate what the guide talks about, even if you never attempt to pick a lock.
~Chris
I've known this method since I was a little kid. It's described in a book called _The Great Brain at the Academy_.