Short-lived network changes used to make miners connect to rogue pool.
Researchers at
Dell SecureWorks
have
discovered
an operation that used BGP hijacking to force bitcoin miners to connect to mining pools under the attackers’ control, thus gaining them a lot of extra mining power and, ultimately, about $83,000 in bitcoins.
New bitcoins are constantly being created through a process called ‘mining’: performing resource-intensive and difficult calculations to create a ‘block’ with a hash value satisfying certain properties. Roughly every ten minutes, a new block worth 25 bitcoins (around $15k) is thus added to the ‘block chain’. To make the payout from mining activity less of a lottery, miners usually cooperate in ‘
mining pools
‘ to share both processing power and rewards.
In a mining pool, clients connect to the pool to receive instructions and share results. A commonly used protocol is the JSON-based
Stratum
mining protocol. Crucially, in this protocol the mining pool
does not authenticate to the clients
.
In the incident discovered by the
Dell
researchers, a rough entity working for a Canadian ISP, or having access to its networks, was able to abuse
BGP
to announce malicious routes, thus hijacking traffic destined for hosting companies such as
Amazon
,
Digital Ocean
and
OVH
.
None of these attacks lasted very long, but they were enough for the attackers to pretend to be the mining pool and tell the mining client to connect to a second server under their control. Lack of authentication in the Stratum protocol meant this happened seamlessly, and some miners didn’t discover anything was amiss until weeks later.
Although the attacks stopped once the upstream provider of the Canadian ISP was notified, it is unclear whether the attack was performed by a rogue (ex-)employee or by an entity having obtained access to the ISP’s network.
BGP hijacking isn’t new, and in the recent past has, for instance, led to the routing of US Internet traffic through
Belarus and Iceland
. The study of the BGP graph can help detect and prevent malicious activity, as
OpenDNS
researcher Dhia Mahjoub will show in the paper ”
Sweeping the IP space: the hunt for evil on the Internet
” that he will present at VB2014.
Cybercriminals’ interest in bitcoins isn’t new either. In another VB2014 paper, ”
Well, that escalated quickly. From penny-stealing malware to multi-million-dollar heists, a quick overview of the bitcoin bonanza in the digital era
“,
Kaspersky
‘s Santiago Pontiroli will take a look at malicious activity aroud bitcoins and other cryptocurrencies.
You can now
register
for
VB2014
, which will take place 24-26 September in Seattle, WA, USA. Or, if you have some interesting last-minute research to contribute, why not
submit an abstract
for one of the seven remaining slots.
Posted on 08 August 2014 by
Martijn Grooten
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