Feeds

How mystery DDoSers tried to take down Bitcoin exchange with 100Gbps crapflood

El Reg talks to anti-DDos bods - who UNMASK the target...

Beginner's guide to SSL certificates

Exclusive Web security firm Incapsula helped a Chinese Bitcoin trader to weather a ferocious denial-of-service attack last month when the volume of inbound traffic to the site peaked at 100Gbps.

The attack against BTC China, a platform where both Bitcoin and Chinese yuan are traded, lasted nine hours and is one of the fiercest on record. But unlike the even bigger 300Gbps attack against Spamhaus back in March no amplification techniques were used in the assault against BTCChina.

Incapsula previously disclosed the appearance of the 24 September attack...

... but only revealed the nature of the assault and named the intended victim during an interview with El Reg on Wednesday.

The attack against BTC China took the form of a SYN flood rather than the DNS amplification-style attack thrown against Spamhaus or more modern application-layer attacks. The attacker balanced the assault between small, high frequency SYN packets, and large, low-frequency SYN packets.

The exchange is currently the third largest in the world.

DNS reflection attacks involve sending a request for a large DNS zone file to a DNS server, with the details of the request forged so that they appear to come from the IP addresses of the intended victim. Only open public-facing DNS servers respond to spoofed requests but there's more than enough of them around to make the tactic viable. Attackers' requests are only a fraction of the size of the responses.

The tactic is more sophisticated than the old school "caveman with a club" SYN flood attacks thrown against BTCChina.

The circumstances of the BTC China attack mean that the unknown assailants had a huge amount of bandwidth at their disposal. "This amount of fire power isn't cheap, or readily available, signifying a big step up in resources pulled together to launch this type of attack," according to Incapsula.

Incapsula co-founder Marc Gaffan told El Reg that the attack was most likely powered by network of compromised servers rather than zombie PCs drones. Commandeering insecure WordPress server installations and the like as a resource for DDoS attacks has become a fairly widespread hacker tactic over recent months.

It's unusual for a 20+ Gigabit attack to last for anything more then an hour. The assault against BTC China was the longest 50+ Gigabit attack Incapsula has ever faced down. "This was a progressive attack," Geffen told El Reg. "The attackers either ran out of resources or money. It's also possible they gave up after they realised they were not making headway."

Geffen added that the BTC China attack was "fairly sophisticated" at least by the standards of old school SYN Flood attacks. "The attackers didn't just use one big cannon," he said.

Bobby Lee chief exec of BTC China told El Reg that the DDoS attack was the first the exchange has faced in two years of operation. He said the effect of the assault was to slow down legitimate access to its site - users complained of patchy access or site unavailability during the time of on an attack in a Reddit thread here. Lee added that he had no idea who might have been behind the attack or their purpose.

"They attackers were out disrupt things," he said. "We don't have a suspicion they were out to cause a [more general] Bitcoin crash."

However, Lee did say that he thought it unlikely that the attack on BTC China was part of a more widespread campaign to attack BitCoin exchanges by hackers hoping to undermine confidence in the currency. Cybercrooks launched DDoS attacks on other exchanges during the summer in a bid to trigger a mass panic-driven sell off of the volatile currency. The tactic allowed them to buy Bitcoins when its price dipped before selling it at a profit once confidence in the market returned.

Although the attack against BTC China was rare in both its magnitude and duration, the increased availability of bandwidth means the scale of attacks is growing all the time, according to Incapsula.

"Even if your network provider has enough bandwidth to keep your site up, DDoS attacks not only suffocate your resources, but your neighbours as well. If you're too noisy, you may be evicted (dropped by your service provider)," it warns.

Rival DDoS mitigation firm Arbor Networks separately published an attack trends study on Wednesday showing that the average volume of traffic in DDoS attacks in the year to date stands at 2.64 Gbps, up 78 per cent from 2012. There's been a fourfold-plus (350 per cent) growth in the number of attacks hitting more than 20Gbps so far this year, as compared to the whole of 2012.

The largest monitored and verified attack size increased significantly to 191Gbps – an August assault against a mystery target not named by Arbor. ®

Protecting users from Firesheep and other Sidejacking attacks with SSL

More from The Register

next story
Spies would need SUPER POWERS to tap undersea cables
Why mess with armoured 10kV cables when land-based, and legal, snoop tools are easier?
Early result from Scots indyref vote? NAW, Jimmy - it's a SCAM
Anyone claiming to know before tomorrow is telling porkies
TOR users become FBI's No.1 hacking target after legal power grab
Be afeared, me hearties, these scoundrels be spying our signals
Jihadi terrorists DIDN'T encrypt their comms 'cos of Snowden leaks
Intel bods' analysis concludes 'no significant change' after whistle was blown
Home Depot: 56 million bank cards pwned by malware in our tills
That's about 50 per cent bigger than the Target tills mega-hack
Hackers pop Brazil newspaper to root home routers
Step One: try default passwords. Step Two: Repeat Step One until success
China hacked US Army transport orgs TWENTY TIMES in ONE YEAR
FBI et al knew of nine hacks - but didn't tell TRANSCOM
Microsoft to patch ASP.NET mess even if you don't
We know what's good for you, because we made the mess says Redmond
NORKS ban Wi-Fi and satellite internet at embassies
Crackdown on tardy diplomatic sysadmins providing accidental unfiltered internet access
prev story

Whitepapers

Providing a secure and efficient Helpdesk
A single remote control platform for user support is be key to providing an efficient helpdesk. Retain full control over the way in which screen and keystroke data is transmitted.
WIN a very cool portable ZX Spectrum
Win a one-off portable Spectrum built by legendary hardware hacker Ben Heck
Saudi Petroleum chooses Tegile storage solution
A storage solution that addresses company growth and performance for business-critical applications of caseware archive and search along with other key operational systems.
Protecting users from Firesheep and other Sidejacking attacks with SSL
Discussing the vulnerabilities inherent in Wi-Fi networks, and how using TLS/SSL for your entire site will assure security.
Security for virtualized datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.