public inbox for bitcoindev@googlegroups.com
 help / color / mirror / Atom feed
From: Arne Brutschy <abrutschy@xylon.de>
To: bitcoin-dev@lists.linuxfoundation.org
Subject: Re: [bitcoin-dev] Significant losses by double-spending unconfirmed transactions
Date: Thu, 16 Jul 2015 16:30:15 +0200	[thread overview]
Message-ID: <55A7BFF7.2050608@xylon.de> (raw)
In-Reply-To: <24662b038abc45da7f3990e12a649b8a@airmail.cc>

Hello,

What are these pre- and post-Hearn-relay drop rules you are speaking
about? Can anybody shed some light on this? (I am aware of the
minrelaytxfee setting proposed in the 0.11.0 release notes, I just
don't see what this has to do with Mike Hearn, BitcoinXT, and whether
there's a code change related to this that I missed).

Related: is there somewhere a chart that plots `estimatefee` over
time? Would be interesting to see how the fee market evolved over
these past weeks.

Regards
Arne

On 15/07/15 05:29, simongreen--- via bitcoin-dev wrote:
> With my black hat on I recently performed numerous profitable 
> double-spend attacks against zeroconf accepting fools. With my
> white hat on, I'm warning everyone. The strategy is simple:
> 
> tx1: To merchant, but dust/low-fee/reused-address/large-size/etc. 
> anything that miners don't always accept.
> 
> tx2: After merchant gives up valuable thing in return, normal tx
> without triggering spam protections. (loltasticly a Mike Hearn
> Bitcoin XT node was used to relay the double-spends)
> 
> Example success story: tx1 paying Shapeshift.io with 6uBTC output
> is not dust under post-Hearn-relay-drop rules, but is dust under 
> pre-Hearn-relay-drop rules, followed by tx2 w/o the output and not 
> paying Shapeshift.io. F2Pool/Eligius/BTCChina/AntPool etc. are all 
> miners who have reverted Hearn's 10x relay fee drop as recommended
> by v0.11.0 release notes and accept these double-spends.
> Shapeshift.io lost ~3 BTC this week in multiple txs. (they're no
> longer accepting zeroconf)
> 
> Example success story #2: tx1 with post-Hearn-relay drop fee,
> followed by tx2 with higher fee. Such stupidly low fee txs just
> don't get mined, so wait for a miner to mine tx2. Bought a silly
> amount of reddit gold off Coinbase this way among other things. I'm
> surprised that reddit didn't cancel the "fools-gold" after tx
> reversal. (did Coinbase guarantee those txs?) Also found multiple
> Bitcoin ATMs vulnerable to this attack. (but simulated attack with
> tx2s still paying ATM because didn't want to go to trouble of good
> phys opsec)
> 
> Shoutouts to BitPay who did things right and notified merchant
> properly when tx was reversed.
> 
> In summary, every target depending on zeroconf vulnerable and lost 
> significant sums of money to totally trivial attacks with high 
> probability. No need for RBF to do this, just normal variations in
> miner policy. Shapeshift claims to use Super Sophisticated Network
> Sybil Attacking Monitoring from Blockcypher, but relay nodes !=
> miner policy.
> 
> Consider yourself warned! My hat is whiter than most, and my skills
> not particularly good.
> 
> What to do? Users: Listen to the experts and stop relying on
> zeroconf. Black hats: Profit!
> 
> _______________________________________________ bitcoin-dev mailing
> list bitcoin-dev@lists.linuxfoundation.org 
> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev

-- 
Arne Brutschy <abrutschy@xylon.de>


  parent reply	other threads:[~2015-07-16 14:38 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-07-15  3:29 [bitcoin-dev] Significant losses by double-spending unconfirmed transactions simongreen
2015-07-15 14:35 ` Tom Harding
2015-07-15 15:18   ` Peter Todd
2015-07-15 15:49     ` Me
2015-07-15 15:53       ` Bastiaan van den Berg
2015-07-15 15:59       ` Peter Todd
2015-07-15 16:06         ` Me
2015-07-15 16:11           ` Pieter Wuille
2015-07-15 16:41             ` Me
2015-07-15 16:12         ` Milly Bitcoin
2015-07-15 18:25           ` Matthieu Riou
2015-07-15 19:32             ` Peter Todd
2015-07-15 19:57               ` Milly Bitcoin
2015-07-16  0:08               ` Matthieu Riou
2015-07-16  5:18                 ` odinn
2015-07-17 11:59                 ` Peter Todd
2015-07-17 12:56                   ` Milly Bitcoin
2015-07-15 17:01 ` Adrian Macneil
2015-07-16 14:30 ` Arne Brutschy [this message]
2015-07-16 14:50   ` Me
2015-07-16 15:33     ` Greg Schvey
2015-07-18 11:43   ` Mike Hearn
2015-07-18 15:09     ` Peter Todd

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=55A7BFF7.2050608@xylon.de \
    --to=abrutschy@xylon.de \
    --cc=bitcoin-dev@lists.linuxfoundation.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox