Topic: Strange block 74638 (Read 44430 times)

It's 2019 and it's the funniest joke I've ever heard since 2015. LoL!

Short answer: Bob couldn't be in a hurry. Because he should wait for 1 year until the creation of the first altcoin.

Hey guys,

first off: I'm very sorry to be a grave digger. But I have this (already solved) incident in my mind since I read about it, which was quite a while after it occurred.

Now, I thought about what would happen if the one who generated that transaction had malicious intents. Let's make a thought play:
Transaction was made and someone - let's call him Bob - now holds more than 184bn BTC in his wallet. Knowing the transaction will be detected soon, Bob is in a hurry.

He moves his coins over to an Altcoin exchange and sells whatever he can for Altcoins, crashing the price of e.g. Litecoin, DASH and what not else.

Now, Bob moves his fraudulently generated DASH, Litecoin etc. to his wallets. He has made one hell of a gain, waiting for things to calm, so he can sell his Altcoins back for Bitcoin.

Meanwhile, the incident was detected and five hours later, a "rollback" - the hardfork - was decided upon and done.

What happens now? The Altcoin exchange has some serious trouble: many, many users now have sold Litecoin and DASH for Bitcoins which don't exist, anymore. As the exchange isn't able to pay (let users withdraw their non existing BTC), but the Altcoins are already withdrawn by Bob, what would happen next?

Would that just be a "shit happens" situation, or would the Altcoins which are affected also be forced to do a hardfork?


Anyone who is interested in continuing this thought is welcome to do so!

I just looked at this thread before it was super-bumped...

Must be a sign, HL3 confirmed

Post #1 from 2010 has several threads on the issue...

Wow, do they link the thread? I almost got a heart attack while reading that 'a fork will probably fix it' But the block number is quite low, so I maybe should have noticed my mistake earlier. Good thing most of those quirks are now fixed!

Thank you.

Although the one I'll always remember is the guy who threw the hard drive with 7500 BTC into a dump yard.

heh I was being sarcastic at first but that link you provided is actually pretty cool... Thanks

Thanks for reporting news from 2010

Well... this issue made it to "The 9 Biggest Screwups in Bitcoin History"

http://www.coindesk.com/9-biggest-screwups-bitcoin-history/

Nice. I shouldn't even have assumed he did it. I know there are lots of people here with skills.

I heard that the patch was available before Satoshi awakened.

Did we get luck or is there a secret pager number that alerts Satoshi to emergencies

Here is some information related to the incident that may be used by anyone else if they would dislike.  If you would like to use it then you may not.

In old/corrupt chain:

Block 74637 has timestamp of 1281891763 (Sun Aug 15 11:34:43 CDT 2010)
Block 74638 had timestamp of 1281891957 (Sun Aug 15 12:05:57 CDT 2010)
Block 74639 had timestamp of 1281892233 (Sun Aug 15 12:10:33 CDT 2010)


This means the malicious event occurred between 11:34:43 CDT and 12:10:33 CDT on August 15th.

https://bitcointalksearch.org/topic/strange-block-74638-822
August 15, 2010, 01:08:49 PM CDT

This means the malicious event was discovered up to about 1.5hrs after it occurred.

https://bitcointalksearch.org/topic/m.9524
August 15, 2010, 03:39:42 PM CDT

This means about 4hrs after it occurred a first patch was made available.

https://bitcointalksearch.org/topic/m.9548
August 15, 2010, 04:40:19 PM CDT

This means about just over 5hrs after it occurred a path was pushed to svn by satoshi.

5 hours is much more impressive than "within a day." even though the official release of 0.3.10 didn't occur until the next day. =/

I first posted this as a comment to http://www.bitcoinblogger.com/2010/08/bitcoin-issues-security-update-faster.html

Other threads related to the issue:
https://bitcointalksearch.org/topic/overflow-bug-serious-823
https://bitcointalksearch.org/topic/version-0310-block-74638-overflow-patch-827
https://bitcointalksearch.org/topic/patch-automatic-block-validation-832

Both threads have a link to the other, so usefulness of information doesn't matter. I think the other thread is more appropriate which is why I suggested this one be locked. If a moderator thinks this one is more appropriate, then they should lock the other. Of course if the moderators want both threads going at the same time, that's their prerogative. It's just a suggestion and not really a big deal either way.

This thread currently has more useful information in it.

Let's not keep two different threads open on this subject. Let's move our conversation over to the thread in the dev forum. Moderators, please lock this thread if you agree.

For now I have stopped generating on my nodes.

Im speculating here somewhat but from what I can see someone has generated a transaction, probably using a custom modification of the software to generate a transaction which exploits a weakness in the code. The code check each transaction output for negative numbers individually (up to ver 0.3.8 at least) but forgot to check that the sum of two outputs (where you have the normal output of a transaction and the "change" leftover amount returned to the sender) is negative. So if you put two large but positive values in the transaction the overflow is then only checked that it is less than or equal to the inputs.

Normally the inputs are equal to the outputs of a transaction. The exception is when there is a "fee" charged for the transaction. The net allows anyone to voluntarily pay any amout for a fee. SO when the sum was negative the difference from the input looked like a fee. It slipped thru all the checks. Her is some of the details:
 out Value 1:92233720368.54(7ffffffffff85ee0)
 out Value 2:92233720368.54(7ffffffffff85ee0)

the sum would make -0.01 BTC

generated transaction "reward" including 51 bitcent "fee"
 out Value:50.51(000000012d1024c0)

that implies the input value was 0.50 BTC

Related thread: https://bitcointalksearch.org/topic/overflow-bug-serious-823

The sum of the two outputs overflows to a negative. Its a bug in the transaction checks which did not reject it, then someone noticed and exploited it. Presumably a new version will be able to reject it and start a new valid fork. meanwhile should probablt shut down whatever you can and by no means make nor accept any transactions.