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Author Topic: Trojan Wallet stealer be careful  (Read 24612 times)
phillipsjk
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June 20, 2011, 02:59:59 AM
 #61

You could use a 2GB SD card with a USB adapter for this because its cheap and has the added advantage of a write protect switch.

There is no reason I can think of that one SD card can't be used with multiple wallet.dat files and you should be able to copy one SD card to another for backup purposes.

SD cards are not a secure floppy replacement: They include CPRM with device revocation. The "Secure" in "Secure digital" means "Secure from the user," not "Securely holds your data."

I Have already said in my first post, computers are too insecure to handle a crypto-currency in the near term.

James' OpenPGP public key fingerprint: EB14 9E5B F80C 1F2D 3EBE  0A2F B3DE 81FF 7B9D 5160
There are several different types of Bitcoin clients. Server-assisted clients like blockchain.info rely on centralized servers to do their network verification for them. Although the server can't steal the client's bitcoins directly, it can easily execute double-spending-style attacks against the client.
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June 20, 2011, 02:05:17 PM
 #62

You could use a 2GB SD card with a USB adapter for this because its cheap and has the added advantage of a write protect switch.

There is no reason I can think of that one SD card can't be used with multiple wallet.dat files and you should be able to copy one SD card to another for backup purposes.

SD cards are not a secure floppy replacement: They include CPRM with device revocation. The "Secure" in "Secure digital" means "Secure from the user," not "Securely holds your data."

I Have already said in my first post, computers are too insecure to handle a crypto-currency in the near term.

Yes, the write protection switch may help you avoid accidentally deleting your keys. Also blocking some virus from getting onto the SD card. A write protected USB is hardware protected, but harder to find.

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Nescio
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June 21, 2011, 03:38:40 AM
 #63

SD cards are not a secure floppy replacement: They include CPRM with device revocation. The "Secure" in "Secure digital" means "Secure from the user," not "Securely holds your data."

Yes, the write protection switch may help you avoid accidentally deleting your keys. Also blocking some virus from getting onto the SD card.

You missed his point. Just like DRM is a euphemism where the R stands for Restrictions rather than Rights, SD cards are securing the industry from the user. Some Windows smartphones will lock-in SD cards. That means after a single insertion into the Windows mobile based phone, they are *completely inaccessible* on *any other device*.
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June 21, 2011, 04:31:12 AM
 #64

....That means after a single insertion into the Windows mobile based phone, they are *completely inaccessible* on *any other device*.

I don't think that the CPRM built into SD Cards actually does that, though I have been putting off re-reading the publicly-available specs.

The Device lock-in seen on the Windows Smart phone may actually be part of the ATA spec instead.


James' OpenPGP public key fingerprint: EB14 9E5B F80C 1F2D 3EBE  0A2F B3DE 81FF 7B9D 5160
cloud9
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June 21, 2011, 08:13:27 AM
 #65

HOW TO: (PUT ALL YOUR BITCOINS IN A OFFLINE WALLET FILE THAT HAS NEVER BEEN ONLINE)

If you use Windows (and you suspect someone might be having a peek inside your computer), try the following:

* Shut down your computer
* Disconnect lan cable, wi-fi, modems, etc. and all other network connectivity
* Switch on your computer and terminate the Bitcoin client
* Rename your wallet.dat file to something like donthack.dat (or any other arbitrary name you choose)
* Restart the Bitcoin client in its offline state
* A new wallet.dat would have been created automatically even though you are offline and not connected to any network
* Create a few receiving addresses in this new wallet.dat file and copy the addresses to a text file named addresses.txt for example
* Close the Bitcoin client in its offline state
* Encrypt your wallet.dat file with a strong password (optional step)
* Copy your (optionally encrypted) wallet.dat file to a removable medium and lock up the removable medium securely as you would have done with traditional paper cash.
* Make as many removable medium backups of your (optionally encrypted) wallet.dat file as you feel comfortable with
* Delete your wallet.dat file from the computer that is still offline
* Rerun Bitcoin client in its offline state to create everyday use spendable wallet - wallet.dat is created automatically again
* Take note of the everyday use spendable wallet's receiving address and copy the address to everyday.txt
* Close the Bitcoin client in its offline state
* Rename your wallet.dat everyday use spendable wallet file on the computer that is still offline to something like spend.dat (or choose any other arbitrary name)
* Run cipher /W:(drive letter) to remove data from available unused disk space (more secure delete - like shredding and not just throwing into the dustbin)
* Rename donthack.dat (or any arbitrary name you chose) file to wallet.dat
* Shut down computer
* Reconnect network connection
* Switch on computer
* Run Bitcoin client again and send bitcoins to addresses in addresses.txt held already in locked-up safekeeping.  Empty the few remaining bitcoins by sending it to addresses in everyday.txt for everyday use spending
* Delete wallet.dat and rename spend.dat (or any other chosen arbitrary name) to wallet.dat

-->  Now the majority of your Bitcoins would be in wallet.dat files that have never been online and should be safely locked up.  Your spendable Bitcoins should also be available for spending with the Bitcoin Client implementation.  To spend safely kept bitcoins - the relevant wallet.dat files should be retrieved from the removable medium where it is locked up - wallet.dat accessed by the Bitcoin Client should be replaced by the stored wallet.dat files - and then you can access the Bitcoins through the Client to be spent.  Just run "bitcoin.exe -rescan" after changing wallet.dat files.


So even if the only copy of your wallet.dat file may be locked up in Fort Knox, you can still send bitcoins to its addresses.

You later re-instate this wallet.dat file at any stage by replacing your wallet.dat file with this wallet.dat file that was kept in safekeeping and running the bitcoin.exe -rescan command.

Remember that with Bitcoin's decentralized nature - you are solely responsible for its safekeeping (just like you are with traditional paper cash).

Important:  Use at own risk and with caution not to overwrite valuable wallet.dat files.  Always make sure that an offline removable medim backup is in place of all wallet.dat files.

Disclaimer:  Postings of Cloud9 are only individual views of opinion and/or musings and/or hypothesisses.  On a non-authoritative, peer-to-peer public forum, you do not need permission from Cloud9 to derive your own conclusions or opinions, so please do.  Calculations and assumptions to be verified.
Nescio
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June 21, 2011, 08:13:38 AM
 #66

I don't think that the CPRM built into SD Cards actually does that, though I have been putting off re-reading the publicly-available specs.

The Device lock-in seen on the Windows Smart phone may actually be part of the ATA spec instead.

From the kb page you linked:
"When the operating system integrates the SD card with your phone:
 .. 3. It locks the card to the phone with an automatically generated key."

No mention of ATA there.

From Wikipedia on CPRM:
"(CPRM/CPPM) is a mechanism for controlling the copying, moving and deletion of digital media on a host device"
"A controversial proposal to add generic key exchange commands (that could be utilized by CPRM and other Content protection technologies) to ATA specifications for removable hard drives was abandoned after outcry in 2001."

The issue is from last year:
"If you pull the SD card out of a Windows Phone 7 mobile, the whole phone stops working. It's bricked. Except for making emergency calls, you might as well carry a rock -- an expensive one, at that. You have to put the original SD card back into the phone for it to work properly.

You can't take the data off using any SD card reader I've been able to find. You can't put the SD card in a different Windows Phone 7 mobile -- that nasty reformatting habit kicks in. It can't read it, can't download or sync the data, nothing."
rocksalt
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June 21, 2011, 02:35:24 PM
 #67

i have my wallet.dat on a usb key in my desk drawer at home.

The usb key has a fingerprint reader on it. when i want to access my wallet,


1.  I insert key, authenticate with my middle finger Wink
2.  copy my wallet to bitcoin dir,
3.  start bitcoin... recieve/send,
4.  close down bitcoin,
5.  recopy to a new dir ( date/time labeled ) on usb drive,
6.  remove key, place in drawer.


oh, and im behind two sets of firewall, have two AV types running in harmony, and have bitlocked by disk.
I also backup my key files to a tape drive with with a strong password for accessing and restoring if needs be.

I run windows Smiley no way in hell anyone if gonna break through those layers to get my file.

So thumb in the eye for linux nerds... i can do it too cos im a PC Tongue lol

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June 21, 2011, 03:45:46 PM
 #68

rocksalt, you are joking I hope. As soon as you do your step 2, ten of your Windows viruses will be sending copies of your wallet to their hacker owners.

As for SD cards and CPRM! What the hell is a Windows 7 phone? it sounds like they should be strangled at birth.

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Grouver (BtcBalance)
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June 21, 2011, 07:41:36 PM
 #69

1) Create volume file off 50mb with Truecrypt.
2) Use a 50 char password or something that cannot be guessed easily.
3) Use some triple encryption algarithm . (Serpent -> Twofish -> AES) and use SHA-512 as Hash algarithm.
4) Generate volume
5) CUT (NOT COPY) wallet.dat on volume.
6) Unmount file

Start using Bitcoin:

1) Open file with Truecrypt
2) Fill in password
3) Mount volume
4) Copy wallet.dat to its original location
5) Start Bitcoin

Stop using Bitcoin:

1) Stop Bitcoin
2) CUT (NOT COPY) wallet.dat to crypted volume.
3) Unmount file


Backup these wallet files not only on your USB stick but also online on your ftp server or whatsoever.

Problem solved temporary...

To bad something that needs security will always need more stuff around it.
Also.. since bitcoin needs its network to support itself you never secure this well.
Some nerdy hacker will eventually break the code.

Combine this with the method of cloud9 mentioned above and you will be fine.

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June 22, 2011, 08:49:49 AM
 #70

i am uber careful when it comes to my home network security ( its what i do for a living )
in the years i've had this setup i havn't been compromised. Even the GF computer is seperated from mine on the network with its own hardware utm firewall no one accesses my machine, biometric access only Tongue
MY wireless is piped only to the internet, no access to internal network, in fact, you'd have to hold a gun to my head in order to get access to my machine and thats windows 7, my servers.. hah!.... one windows, one opensuse Tongue and they sit on a segregated network with ports locked down so much, a gnats ass by comparison is the channel tunnel.

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phillipsjk
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June 22, 2011, 04:55:34 PM
 #71

And I used to think a harvard architecture  (read-only code) was impenetrable until I read about that voting machine hack using return-oriented programming.

Just because you wouldn't be able to break into your computer does not imply nobody else can. Do you leave "Automatic Updates" enabled? If not, you may be open to known security exploits. If true, you are putting a lot of trust in your OS vendor.

James' OpenPGP public key fingerprint: EB14 9E5B F80C 1F2D 3EBE  0A2F B3DE 81FF 7B9D 5160
allinvain
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June 22, 2011, 08:02:33 PM
 #72

trust nobody is the modus operandi in the bitcoin world...

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June 22, 2011, 08:51:51 PM
 #73

trustless medium is trustless.

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June 22, 2011, 10:01:37 PM
 #74

Alright, since we are talking so much about geeks and nerds here...I that direction I could only call myself an aspiring novice Wink
I have been reading in the forum and elswhere for approx. two weeks now and didn't find sufficent answers to some problems/questions. Maybe you could enlighten me !

So, a few questions about security:

1) How long do you have to let the client run after the the confirmation window "Payment sent" till you can close the client AND your payment is really transmitted (Do you need to wait to have confirmations? What happens if the client says "0/? offline" ?)

=> two micropayments 0,001 as a test still have not yet emerged after 24 hrs. (min. 0,0005 fee)

2) With regard to creating an offline wallet:

How do the addresses get created offline and still made sure, that each address is unique (if there is never a connection to the network? - Couldn't different people create the same addresses and/or public keys by accident?)

3) Can you copy the blockchain from a "used" potentially infected computer to implement in new installation without infecting the new installation too? (only partly about security and partly about convenience)
(Imagine you create a new "savings-account" wallet and put it away in vault or anything, then you keep saving for the next ten years and when you finally want to spend it or some of it, it takes 3 weeks do download the blockchain....(did it yesterday and it took 15 hours; two weeks earlier "only" 7 hours).


4) How many addresses do get created with the new wallet?
If I am informed correctly about a hundred with creation - can you read them out somehow?
When you press new address it takes a considerable amount of time till the new address appears in the reciving addressbook-why if it is already created?

5) Regarding the idea to create an offline wallet by disconecting the computer from network.
Isn't this also risky? I'd say you would not only have it disconected but have the hard disc completly shredded, then an os installed, then client and wallet creation. After securing the "virgin-wallet" shredding the harddisk again. Isn't that the only safe way Huh IF NOT please tell me (it is pretty laborious).

6) If I understand correctly the wallet file is exposed whenever you are using the client. If that is correct than every single wallet.dat is not secure (except for the offline created and never online used ones), right? So basically your "everyday" wallet is always insecure...(even if it's not 250K I'd still pissed to lose 10-20 coins because of this).


All right, I am going to come up with some more. But as an appetizer Wink

Thank you!
 



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phillipsjk
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June 22, 2011, 11:44:20 PM
 #75

1) How long do you have to let the client run after the the confirmation window "Payment sent" till you can close the client AND your payment is really transmitted (Do you need to wait to have confirmations? What happens if the client says "0/? offline" ?)

If it says offiline, you may not be connected to anybody, so may not have broadcasted your transaction. I would wait for at least 1 confirmation before closing the client. If you are wondering if your transaction was broadcasted, you can check Bitcoin charts' list of unconfirmed tansactions to see if it is listed there.

Quote
How do the addresses get created offline and still made sure, that each address is unique (if there is never a connection to the network? - Couldn't different people create the same addresses and/or public keys by accident?)
The addresses are 160bit. Collisions can happen, but likely won't until 2^80 are in existence. To put that in perspective, 48bit MAC address space (uniquely assigned to every device that may connect to a network) is expected to last 100 years. (they are already moving to 64 bit MAC addresses.)

Quote
3) Can you copy the blockchain from a "used" potentially infected computer to implement in new installation without infecting the new installation too? (only partly about security and partly about convenience)
With transaction volume going up exponentially, the first 2 years worth are likely to be insignificant.

Quote
5) Regarding the idea to create an offline wallet by disconecting the computer from network.
Isn't this also risky? I'd say you would not only have it disconected but have the hard disc completly shredded, then an os installed, then client and wallet creation. After securing the "virgin-wallet" shredding the harddisk again. Isn't that the only safe way Huh IF NOT please tell me (it is pretty laborious).

You can use a "live CD" on read-only media to boot; ignoring the hard-disk.

Quote
6) If I understand correctly the wallet file is exposed whenever you are using the client. If that is correct than every single wallet.dat is not secure (except for the offline created and never online used ones), right? So basically your "everyday" wallet is always insecure...(even if it's not 250K I'd still pissed to lose 10-20 coins because of this).

Your wallet.dat is as secure as the user account/machine you store it in. I would argue that modern computers are insecure, so I agree, the "everyday" wallet is likely to be insecure. I don't store a lot of money in my everyday wallet holding paper money either.

Sorry for not answering question number 4. I don't like how the default client handles wallets. The pre-generated addresses were implemented to increase the likelyhood that a backup wallet would have all the addresses you are using.

James' OpenPGP public key fingerprint: EB14 9E5B F80C 1F2D 3EBE  0A2F B3DE 81FF 7B9D 5160
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June 22, 2011, 11:45:39 PM
 #76

in the years i've had this setup i havn't been compromised.

How do you know? Are you doing a daily memory dump and auditing it? Smiley
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June 23, 2011, 12:21:18 AM
 #77

3) Can you copy the blockchain from a "used" potentially infected computer to implement in new installation without infecting the new installation too?

Strictly speaking you can't assume so. Practically, it depends on what attacks are possible against the transfer medium and the blockchain itself. For example your OS might prescan inserted USB sticks and contain vulnerabilities in this code (this is a known attack vector), regardless of any autoplay settings. The blockchain could be doctored to include buffer overflow initiated code (the client could contain parsing bugs, I bet this has not been vetted yet). The blockchain could even be replaced by something like a specially crafted PDF file with attack code in it. There was a nice Adobe bug where when you installed the suite it would add a PDF parsing service to Windows which had a buffer overflow vulnerability. In a default setup Windows is set to periodically scan for new files for its indexing service. When the indexer comes across a PDF file, the Adobe service would be called to parse it, boom, infected. So just having the file on the system, without opening it, would infect it.

A similar exploit was possible on the Amiga, in ancient times (Kickstart 1.2) when the OS detected a filesystem problem it would automatically invoke the checkdisk program (pretty advanced for the time), but would try to load it from amongst others the floppy. Floppies were autodetected, so if you inserted one with a purposefully corrupted filesystem, and put your own doctored checkdisk program on there it would autoexecute. This in light that bootsector viruses already existed but were only executed when booting from them.
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June 23, 2011, 01:58:14 AM
 #78

Bitcoin developers, please, please, please do create encrypted wallet functionality, so that I can run bitcoin on my malware infested windows computer while enjoying false sense of security.



+1.  Agreed.  This should be default.

"We will not find a solution to political problems in cryptography, but we can win a major battle in the arms race and gain a new territory of freedom for several years.

Governments are good at cutting off the heads of a centrally controlled networks, but pure P2P networks are holding their own."
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June 24, 2011, 08:43:22 PM
 #79

some sample code for a wallet stealer in metasploit:

https://dev.metasploit.com/redmine/projects/framework/repository/revisions/12993/entry/modules/post/windows/gather/bitcoin_jacker.rb
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June 26, 2011, 10:08:15 PM
 #80

i have my wallet.dat on a usb key in my desk drawer at home.

The usb key has a fingerprint reader on it. when i want to access my wallet,


1.  I insert key, authenticate with my middle finger Wink
2.  copy my wallet to bitcoin dir,
3.  start bitcoin... recieve/send,
4.  close down bitcoin,
5.  recopy to a new dir ( date/time labeled ) on usb drive,
6.  remove key, place in drawer.


oh, and im behind two sets of firewall, have two AV types running in harmony, and have bitlocked by disk.
I also backup my key files to a tape drive with with a strong password for accessing and restoring if needs be.

I run windows Smiley no way in hell anyone if gonna break through those layers to get my file.

So thumb in the eye for linux nerds... i can do it too cos im a PC Tongue lol


LOL @ middle finger ... seriously why does it always have to be the MIDDLE FINGER ? Cheesy
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