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Topic: If you used Brainwallet.org - MUST READ! - Security Breach! - page 7. (Read 52821 times)

full member
Activity: 210
Merit: 100
Clearly a new solution for the security issues it required for mass adoption for laypeople - the hardware wallets, if they can be made very affordable, will certainly be a move in that direction.
vip
Activity: 1316
Merit: 1043
👻
Which is great if you know what you are doing, but people in life are not prepared to lose money if their hard drive crashes or such. It doesn't matter how loud you yell at users for them to back up their private keys - they usually don't.
Jan
legendary
Activity: 1043
Merit: 1002
The block chain is a public vault. Anyone can use it. Access to specific funds is determined by the key used. The security of your money depends on your ability to protect your key. Creating a unique key from the start is an important step in protecting your key.

When you use a key that someone else already has...



...they can access any funds attached to that key.

The most important thing new users should learn before using Bitcoin is how to protect their key.

+1
Keep your private keys private
legendary
Activity: 1862
Merit: 1114
WalletScrutiny.com
I still think this thread is very useful - I know you feel people who are new and not tech savvy deserve to lose their bitcoins, but that is not an attitude that will lead to widespread adoption.  I would be okay changing it to:  "If you use Brainwallet.org - MUST READ! - Security Risk!" if you think that is more accurate.  My post was not meant to be libel in anyway, it seemed like a security breach to me at the time and it is a vulnerability with brain wallets more people need to be made aware.

If you have no problem lying to people, implicitly calling others that set up services like brainwallet fraudsters, leave it as is. If honesty counts in your value system, maybe change it to the truth. This is not about saying that you didn't deserve better.
full member
Activity: 210
Merit: 100
I still think this thread is very useful - I know you feel people who are new and not tech savvy deserve to lose their bitcoins, but that is not an attitude that will lead to widespread adoption.  I would be okay changing it to:  "If you use Brainwallet.org - MUST READ! - Security Risk!" if you think that is more accurate.  My post was not meant to be libel in anyway, it seemed like a security breach to me at the time and it is a vulnerability with brain wallets more people need to be made aware.
legendary
Activity: 1862
Merit: 1114
WalletScrutiny.com
OP: mind changing the topic? I find it quite offensive to the guy who runs brainwallet.org despite the above mentioned reservations.
You only make a fool of yourself if you use a weak password like you did and then blame the service of stealing your money.
full member
Activity: 210
Merit: 100
Thanks, it seems to me then compressed is more secure simply since less people use it so hackers less likely to include it in a rainbow table.  Clearly, though, that is not a replacement for a strong passphrase.
hero member
Activity: 504
Merit: 500
Somebody told me that he generated a keypair with the passphrase 'dog' one year ago when the bitcoin had a value of 10$ and deposited 0.01 BTC.
The amount was taken in a half an hour.
No human would make such an effort for 10 cents.
So it seems to be sure that some bots are scanning the network for  brainwallets.
But that doesn't mean that brainwallets are not secure if used correctly.
full member
Activity: 196
Merit: 100
Btw, can someone expalin to me the difference between the compressed and uncompressed keys?

Since I'm here, I'll take a punt, but I'm no expert (and I expect a cross post will happen by the time I finish).

The public key is a 64 byte (512 bit) number derived by ECC algorithm from the private key. It consists of the X and Y coordinates of a point on the curve. However one of these coordinates is redundant, so the compressed key just uses the X coordinate which shortens the public key length by half. In practice both versions are hashed to 160bit hash value in the block chain. If you take a look at the script I linked above, you can see the procedure for generating both the uncompressed and compressed keys/addresses.

I assume they are equally secure (others may correct me). The reason that only the uncompressed stfu! was compromised is (I guess) that most people just use this one and the hacker did not bother to build the rainbow table for the compressed one (lazy hacker as the ECC is the expensive part, so the only cost of having both is storage space).

Hope this helps. (Yup, crosspost, but not on this topic so I'll post anyway)
legendary
Activity: 1400
Merit: 1013
The speed (seconds) with which the funds were redirected make it clear it was a bot.
I don't think you understand what a rainbow table is.

Somebody generated the exact same brainwallet you did, long before you ever thought of using that passphrase.

They've actually generated millions of brainwallets, and they're just waiting for someone naive enough to use the same weak passprases and deposit money into one of their addresses.

Anything less than 16 random words is too short as a passphrase. Not a 16 word phrase from your favourite work of literature, not some TV character's 16 word catchphrase with a few simple letter substitutions and random punctuation characters thrown in.

16 words that have never before been grouped together into the same context by any human that has ever lived.

If you can't generate and remember a random passphrase this long you shouldn't use brainwallets.
full member
Activity: 210
Merit: 100
Btw, can someone expalin to me the difference between the compressed and uncompressed keys?  Seems both are accepted by Bitcoin-QT (though uncompressed priv key cannot be used to access compress public or vice-versa).  Is one type more secure than the other?  In my example, the stfu! compressed version was not compromised, only the uncompressed version was (I channeled the BTC through both bitcoin addresses).  The speed (seconds) with which the funds were redirected make it clear it was a bot.
full member
Activity: 210
Merit: 100
As I said, it was a small loss - the equivalent of $12.  Could have been worse and hopefully others will learn from my errors.  Still, a warning on the website about the need to use a strong passphrase would be a good idea.  Ninja's bitaddress generator will not even create codes for such short passphrases I see to protect newbs from themselves.
full member
Activity: 196
Merit: 100
stfu! looks correct ...

Code:
pi@tvpi ~ $ python bitaddr_brain.py
Enter keyphrase: stfu!
stfu!
keyphrase=[stfu!]
f8ec8429e5922a17fa3b8f2810949381bc921adef69e42dab30f579ddd5731e9  priv key HEX
5Khv1RwWj3jkJnewDYxdDXFwyJiBppER3t5c291G5pL4RuuxhMr  private key WIF
L5Zaxu5cCb5g9WWSJQ4WrGYydXAnn3UD9iTKa2L9aFu88xBCwgdV  private key WIF (comp)
041b35508e152d9470a5e94160a13647da0de4dc017fad205b0ee99ef8526c6f878509cf4908aceb8428f22e4b3bde67342ec4349b187f67c974b07f441a5711df  public key
318043492132656822b2cec2b5d2465c067889b5  uncompressed hash (pubkey)
15WjmFwpZ1mp3fG55JGoGv3p5y9jtehEB2  address
031b35508e152d9470a5e94160a13647da0de4dc017fad205b0ee99ef8526c6f87  comp pubkey
091a107374ffc6854910a469b96fe970674a8fa6  hash (compressed pubkey)
1q8JhnKe7LjBZjCrwfDYT5LkkGo9GuEEx  compressed address

I feel for your loss, but its a useful wakeup call for the rest of us. I think I'll stick with bitcoin_qt for now.
hero member
Activity: 504
Merit: 500
The owner of that site needs to shut it down. This kind of thing was inevitable and we warned about it from the start. Someone has calculated a rainbow table and the passphrase you chose is in it.

Which wallet software did you import the key into? Do we need to put a warning about this site into wallet apps? We need to find some way to kill this stupid and dangerous site asap.
I think we shouldn't make such of assertions without any evidence.
If someone calculated a rainbow table (and almost sure that have done more people) then it has nothing to do with the site owner.
It was the negligence of the user to use a simple password and the opportunism of a dishonest hacker which caused.
Is the Bank guilty if somebody take over your online account because you used 123456 as password ?
You shouldn't use something what you don't understand.
full member
Activity: 210
Merit: 100
hey guys,
   Sorry I just logged back on.  As I said, I was just fooling around so I did use a very short passphrase "stfu!" just to see how it works and I imported in into Bitcoin-qt using the importprivkey command.  I actually made two keys from this - one with Point Compression and one without Point Compression - only the uncompressed address was compromised.
    Anyway, newbie mistake - glad I learned it on  .178BTC as opposed to much more.  Though this experience has taught me a brain wallet not for me - any phrase I could remember would not be secure and if I added enough misspellings and character substitutions I would likely forget it eventually.  Will just stick to my paper wallets I generated offline using Ninja's script at bitcoinaddress.org
    I feel better actually, since even though all my trojan scans came back negative, I was still worried maybe somehow my computer was compromised.  The only compromise was my noobness! Hope others learn from me error.
mechs
hero member
Activity: 938
Merit: 500
https://youengine.io/
My only thought is the brainwallet website has been compromised instead and some bot is stealing the private keys

No. You just used a weak passphrase. They have *huge* lists of keys already calculated in advance from all kinds of weak passphrases, they knew your passphrase (and with it the key) already long before you even had the idea to use a brain wallet. They are sitting somewhere with a huge list of such weak keys, permanently scanning the network for new transactions and waiting for your coins to arrive at one of their addresses.

Next time you should use a long computer generated random passphrase. Use a tool like pwgen that creates pronounceable random nonsense (not in any dictionary) words, so its easy to remember but still completely random.
legendary
Activity: 1862
Merit: 1114
WalletScrutiny.com
The owner of that site needs to shut it down. This kind of thing was inevitable and we warned about it from the start. Someone has calculated a rainbow table and the passphrase you chose is in it.

Which wallet software did you import the key into? Do we need to put a warning about this site into wallet apps? We need to find some way to kill this stupid and dangerous site asap.
The owner of that site should at least warn that "correct horse battery staple" is a particularly bad password. The fact that barely any bitcoins flow through this one tells me that there is no significant amount of noobs using the site. With mass adoption I bet at least 1% of all users would be thankful for this "random" suggestion and go with it. Brainwallet instead should give the user feedback on how secure his key is, although this might make them feel safe where they shouldn't, it can tell them when they are not safe where they feel safe.
Else it should suggest to actually use it to use the github version and verify that the signature of these 4 persons confirms the version to not be tampered with.

How could be compromised a brainwallet ?
Breaking known algorithms should we exclude because that would affect all kind of wallets.

You have a javascript brainwallet like brainwallet.org or bitaddress.org or namecoinia.org.
1. It has a connection to the internet and transmitting your private keys.
You can avoid this if you save the page on your computer and switch off the internet connection when you are generating the keypairs.
Alternatively you can do it in a virtualbox container which has no internet connection.
2. You are generating a random keypair however it isn't random in the reality, but follows a deterministic or stored pattern known to the brainwallet creator.
The source is known (javascript) but it is obfuscated and difficult to check it. In this case it doesn't matter if you are offline or online.

Best if you generate deterministic wallet with a passphrase which is random and long enough but you choose it and your computer is offline.
In this case I cannot imagine how could the brainwallet creator know the private keys.

Of  course they are other attack possibilities also but they are not brainwallet specific.
If you downloaded from a pishing site, you have some trojans on your computer or you have written the passphrase on a paper and let on the table on your bureau.

If the minimized/obfuscated code reduces the entropy by doing something like changing this
privkey_hex = sha256(keyphrase).hexdigest() to this:
privkey_hex = sha256("evilhackersalt" + sha256(keyphrase)[:3]).hexdigest()
you would get "totally random" keys with every change to your input, but the attacker would actually be the only one to know your private key in a trivial list of a million keys.

You would only notice this once you try to use your password on a non-poisoned brainwallet. Good luck finding your money if you didn't also backup your priv key, just in case this attacker needs time to swipe your money.
hero member
Activity: 896
Merit: 532
Former curator of The Bitcoin Museum
I decided to mess around and make a brain wallet.  I used the website www.brainwallet.org.  Supposively, this javascript is client side only.  Anyway, I made a brain wallet and decided to test it.  I moved my spare change (I keep most of my BTC in cold storage) about 0.178 BTC to the new brain wallet I made "15WjmFwpZ1mp3fG55JGoGv3p5y9jtehEB2".  Literally within seconds, it was moved to a new bitcoin address not owned by me "1Lp3S4PajwhuFCyrAXSFdVGxLuqTsXtVQC" https://blockchain.info/address/15WjmFwpZ1mp3fG55JGoGv3p5y9jtehEB2

I am very security conscience and am certain my wallet file was not compromised.  My only thought is the brainwallet website has been compromised instead and some bot is stealing the private keys generated there and then instantly transfering any funds deposited to these compromised wallets to their own bitcoin addresses.  DO NOT USE www.brainwallet.org and if you have used it, then immediately move your funds to a new location ASAP.

I am not complaining though, I only lost 0.178BTC - it could have been much worse.


Tell us what pass phrase you used already!! Smiley
hero member
Activity: 767
Merit: 500
If you can't reveal it because you use that password in multiple places then guess what - that's how they got your password in the first place - by stealing it from some other place you used it.

indeed, it would make sense for an attacker to find as many compromised password lists as possible (hint: there was one for mtgox a while back) and use those as seeds as well.

Quote
A brain wallet when done right is perfectly fine.

Anything, done well, is perfectly fine!  The problem is that there are so many bad ways to do a brain wallet, for example:

 - picking a weak passphrase
 - forgetting your passphrase
 - not understanding Change addresses, and losing bitcoins

and it's so trivially easy to compromise a brain wallet with a bad passphrase, that it's probably better, for most users, to use an alternative form of key generation and storage.   I would never recommend a brain wallet to a new user, but I would recommend blockchain.info with OTP and a strong passphrase to a new user.

Will
newbie
Activity: 24
Merit: 0
I did a small investigation some time ago to see how widespread the problem was, and these were the results:

 - Sent 0.001 BTC to an address generated with a password you will find in any top 10 common password list. Taken immediately.
 - Sent 0.001 BTC to an address generated with a six digit password. Taken immediately.
 - Sent 0.001 BTC to an address generated with the same six digit password as above, but with Point Conversion set to "Compressed". Untouched.
 - Sent 0.001 BTC to an address generated with an upper/lower/digit six character randomly generated password, normal Point Conversion. Untouched.

Someone is definitely out there grabbing things from weak-passworded wallets, but even a six-character random password thwarts them.


Edit:
Mechs, tell us which password you used. It's already compromised, so there should be no harm in revealing it.
If you can't reveal it because you use that password in multiple places then guess what - that's how they got your password in the first place - by stealing it from some other place you used it.
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