Entries Tagged "Internet"

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Lessons From the Dyn DDoS Attack

A week ago Friday, someone took down numerous popular websites in a massive distributed denial-of-service (DDoS) attack against the domain name provider Dyn. DDoS attacks are neither new nor sophisticated. The attacker sends a massive amount of traffic, causing the victim’s system to slow to a crawl and eventually crash. There are more or less clever variants, but basically, it’s a datapipe-size battle between attacker and victim. If the defender has a larger capacity to receive and process data, he or she will win. If the attacker can throw more data than the victim can process, he or she will win.

The attacker can build a giant data cannon, but that’s expensive. It is much smarter to recruit millions of innocent computers on the internet. This is the “distributed” part of the DDoS attack, and pretty much how it’s worked for decades. Cybercriminals infect innocent computers around the internet and recruit them into a botnet. They then target that botnet against a single victim.

You can imagine how it might work in the real world. If I can trick tens of thousands of others to order pizzas to be delivered to your house at the same time, I can clog up your street and prevent any legitimate traffic from getting through. If I can trick many millions, I might be able to crush your house from the weight. That’s a DDoS attack ­ it’s simple brute force.

As you’d expect, DDoSers have various motives. The attacks started out as a way to show off, then quickly transitioned to a method of intimidation ­ or a way of just getting back at someone you didn’t like. More recently, they’ve become vehicles of protest. In 2013, the hacker group Anonymous petitioned the White House to recognize DDoS attacks as a legitimate form of protest. Criminals have used these attacks as a means of extortion, although one group found that just the fear of attack was enough. Military agencies are also thinking about DDoS as a tool in their cyberwar arsenals. A 2007 DDoS attack against Estonia was blamed on Russia and widely called an act of cyberwar.

The DDoS attack against Dyn two weeks ago was nothing new, but it illustrated several important trends in computer security.

These attack techniques are broadly available. Fully capable DDoS attack tools are available for free download. Criminal groups offer DDoS services for hire. The particular attack technique used against Dyn was first used a month earlier. It’s called Mirai, and since the source code was released four weeks ago, over a dozen botnets have incorporated the code.

The Dyn attacks were probably not originated by a government. The perpetrators were most likely hackers mad at Dyn for helping Brian Krebs identify ­ and the FBI arrest ­ two Israeli hackers who were running a DDoS-for-hire ring. Recently I have written about probing DDoS attacks against internet infrastructure companies that appear to be perpetrated by a nation-state. But, honestly, we don’t know for sure.

This is important. Software spreads capabilities. The smartest attacker needs to figure out the attack and write the software. After that, anyone can use it. There’s not even much of a difference between government and criminal attacks. In December 2014, there was a legitimate debate in the security community as to whether the massive attack against Sony had been perpetrated by a nation-state with a $20 billion military budget or a couple of guys in a basement somewhere. The internet is the only place where we can’t tell the difference. Everyone uses the same tools, the same techniques and the same tactics.

These attacks are getting larger. The Dyn DDoS attack set a record at 1.2 Tbps. The previous record holder was the attack against cybersecurity journalist Brian Krebs a month prior at 620 Gbps. This is much larger than required to knock the typical website offline. A year ago, it was unheard of. Now it occurs regularly.

The botnets attacking Dyn and Brian Krebs consisted largely of unsecure Internet of Things (IoT) devices ­ webcams, digital video recorders, routers and so on. This isn’t new, either. We’ve already seen internet-enabled refrigerators and TVs used in DDoS botnets. But again, the scale is bigger now. In 2014, the news was hundreds of thousands of IoT devices ­ the Dyn attack used millions. Analysts expect the IoT to increase the number of things on the internet by a factor of 10 or more. Expect these attacks to similarly increase.

The problem is that these IoT devices are unsecure and likely to remain that way. The economics of internet security don’t trickle down to the IoT. Commenting on the Krebs attack last month, I wrote:

The market can’t fix this because neither the buyer nor the seller cares. Think of all the CCTV cameras and DVRs used in the attack against Brian Krebs. The owners of those devices don’t care. Their devices were cheap to buy, they still work, and they don’t even know Brian. The sellers of those devices don’t care: They’re now selling newer and better models, and the original buyers only cared about price and features. There is no market solution because the insecurity is what economists call an externality: It’s an effect of the purchasing decision that affects other people. Think of it kind of like invisible pollution.

To be fair, one company that made some of the unsecure things used in these attacks recalled its unsecure webcams. But this is more of a publicity stunt than anything else. I would be surprised if the company got many devices back. We already know that the reputational damage from having your unsecure software made public isn’t large and doesn’t last. At this point, the market still largely rewards sacrificing security in favor of price and time-to-market.

DDoS prevention works best deep in the network, where the pipes are the largest and the capability to identify and block the attacks is the most evident. But the backbone providers have no incentive to do this. They don’t feel the pain when the attacks occur and they have no way of billing for the service when they provide it. So they let the attacks through and force the victims to defend themselves. In many ways, this is similar to the spam problem. It, too, is best dealt with in the backbone, but similar economics dump the problem onto the endpoints.

We’re unlikely to get any regulation forcing backbone companies to clean up either DDoS attacks or spam, just as we are unlikely to get any regulations forcing IoT manufacturers to make their systems secure. This is me again:

What this all means is that the IoT will remain insecure unless government steps in and fixes the problem. When we have market failures, government is the only solution. The government could impose security regulations on IoT manufacturers, forcing them to make their devices secure even though their customers don’t care. They could impose liabilities on manufacturers, allowing people like Brian Krebs to sue them. Any of these would raise the cost of insecurity and give companies incentives to spend money making their devices secure.

That leaves the victims to pay. This is where we are in much of computer security. Because the hardware, software and networks we use are so unsecure, we have to pay an entire industry to provide after-the-fact security.

There are solutions you can buy. Many companies offer DDoS protection, although they’re generally calibrated to the older, smaller attacks. We can safely assume that they’ll up their offerings, although the cost might be prohibitive for many users. Understand your risks. Buy mitigation if you need it, but understand its limitations. Know the attacks are possible and will succeed if large enough. And the attacks are getting larger all the time. Prepare for that.

This essay previously appeared on the SecurityIntelligence website.

Posted on November 8, 2016 at 6:25 AMView Comments

How Different Stakeholders Frame Security

Josephine Wolff examines different Internet governance stakeholders and how they frame security debates.

Her conclusion:

The tensions that arise around issues of security among different groups of internet governance stakeholders speak to the many tangled notions of what online security is and whom it is meant to protect that are espoused by the participants in multistakeholder governance forums. What makes these debates significant and unique in the context of internet governance is not that the different stakeholders often disagree (indeed, that is a common occurrence), but rather that they disagree while all using the same vocabulary of security to support their respective stances. Government stakeholders advocate for limitations on WHOIS privacy/proxy services in order to aid law enforcement and protect their citizens from crime and fraud. Civil society stakeholders advocate against those limitations in order to aid activists and minorities and protect those online users from harassment. Both sides would claim that their position promotes a more secure internet and a more secure society — ­and in a sense, both would be right, except that each promotes a differently secure internet and society, protecting different classes of people and behaviour from different threats.

While vague notions of security may be sufficiently universally accepted as to appear in official documents and treaties, the specific details of individual decisions­ — such as the implementation of dotless domains, changes to the WHOIS database privacy policy, and proposals to grant government greater authority over how their internet traffic is routed­ — require stakeholders to disentangle the many different ideas embedded in that language. For the idea of security to truly foster cooperation and collaboration as a boundary object in internet governance circles, the participating stakeholders will have to more concretely agree on what their vision of a secure internet is and how it will balance the different ideas of security espoused by different groups. Alternatively, internet governance stakeholders may find it more useful to limit their discussions on security, as a whole, and try to force their discussions to focus on more specific threats and issues within that space as a means of preventing themselves from succumbing to a façade of agreement without grappling with the sources of disagreement that linger just below the surface.

The intersection of multistakeholder internet governance and definitional issues of security is striking because of the way that the multistakeholder model both reinforces and takes advantage of the ambiguity surrounding the idea of security explored in the security studies literature. That ambiguity is a crucial component of maintaining a functional multistakeholder model of governance because it lends itself well to high-level agreements and discussions, contributing to the sense of consensus building across stakeholders. At the same time, gathering those different stakeholders together to decide specific issues related to the internet and its infrastructure brings to a fore the vast variety of definitions of security they employ and forces them to engage in security-versus-security fights, with each trying to promote their own particular notion of security. Security has long been a contested concept, but rarely do these contestations play out as directly and dramatically as in the multistakeholder arena of internet governance, where all parties are able to face off on what really constitutes security in a digital world.

We certainly saw this in the “going dark” debate: e.g. the FBI vs. Apple and their iPhone security.

Posted on October 24, 2016 at 6:03 AMView Comments

DDoS Attacks against Dyn

Yesterday’s DDoS attacks against Dyn are being reported everywhere.

I have received a gazillion press requests, but I am traveling in Australia and Asia and have had to decline most of them. That’s okay, really, because we don’t know anything much of anything about the attacks.

If I had to guess, though, I don’t think it’s China. I think it’s more likely related to the DDoS attacks against Brian Krebs than the probing attacks against the Internet infrastructure, despite how prescient that essay seems right now. And, no, I don’t think China is going to launch a preemptive attack on the Internet.

Posted on October 22, 2016 at 8:47 AMView Comments

Someone Is Learning How to Take Down the Internet

Over the past year or two, someone has been probing the defenses of the companies that run critical pieces of the Internet. These probes take the form of precisely calibrated attacks designed to determine exactly how well these companies can defend themselves, and what would be required to take them down. We don’t know who is doing this, but it feels like a large nation state. China or Russia would be my first guesses.

First, a little background. If you want to take a network off the Internet, the easiest way to do it is with a distributed denial-of-service attack (DDoS). Like the name says, this is an attack designed to prevent legitimate users from getting to the site. There are subtleties, but basically it means blasting so much data at the site that it’s overwhelmed. These attacks are not new: hackers do this to sites they don’t like, and criminals have done it as a method of extortion. There is an entire industry, with an arsenal of technologies, devoted to DDoS defense. But largely it’s a matter of bandwidth. If the attacker has a bigger fire hose of data than the defender has, the attacker wins.

Recently, some of the major companies that provide the basic infrastructure that makes the Internet work have seen an increase in DDoS attacks against them. Moreover, they have seen a certain profile of attacks. These attacks are significantly larger than the ones they’re used to seeing. They last longer. They’re more sophisticated. And they look like probing. One week, the attack would start at a particular level of attack and slowly ramp up before stopping. The next week, it would start at that higher point and continue. And so on, along those lines, as if the attacker were looking for the exact point of failure.

The attacks are also configured in such a way as to see what the company’s total defenses are. There are many different ways to launch a DDoS attack. The more attack vectors you employ simultaneously, the more different defenses the defender has to counter with. These companies are seeing more attacks using three or four different vectors. This means that the companies have to use everything they’ve got to defend themselves. They can’t hold anything back. They’re forced to demonstrate their defense capabilities for the attacker.

I am unable to give details, because these companies spoke with me under condition of anonymity. But this all is consistent with what Verisign is reporting. Verisign is the registrar for many popular top-level Internet domains, like .com and .net. If it goes down, there’s a global blackout of all websites and e-mail addresses in the most common top-level domains. Every quarter, Verisign publishes a DDoS trends report. While its publication doesn’t have the level of detail I heard from the companies I spoke with, the trends are the same: “in Q2 2016, attacks continued to become more frequent, persistent, and complex.”

There’s more. One company told me about a variety of probing attacks in addition to the DDoS attacks: testing the ability to manipulate Internet addresses and routes, seeing how long it takes the defenders to respond, and so on. Someone is extensively testing the core defensive capabilities of the companies that provide critical Internet services.

Who would do this? It doesn’t seem like something an activist, criminal, or researcher would do. Profiling core infrastructure is common practice in espionage and intelligence gathering. It’s not normal for companies to do that. Furthermore, the size and scale of these probes — and especially their persistence — points to state actors. It feels like a nation’s military cybercommand trying to calibrate its weaponry in the case of cyberwar. It reminds me of the US’s Cold War program of flying high-altitude planes over the Soviet Union to force their air-defense systems to turn on, to map their capabilities.

What can we do about this? Nothing, really. We don’t know where the attacks come from. The data I see suggests China, an assessment shared by the people I spoke with. On the other hand, it’s possible to disguise the country of origin for these sorts of attacks. The NSA, which has more surveillance in the Internet backbone than everyone else combined, probably has a better idea, but unless the US decides to make an international incident over this, we won’t see any attribution.

But this is happening. And people should know.

This essay previously appeared on Lawfare.com.

EDITED TO ADD: Slashdot thread.

EDITED TO ADD (9/15): Podcast with me on the topic.

EDITED TO ADD (10/6): More.

Posted on September 13, 2016 at 2:09 PMView Comments

The Difficulty of Routing around Internet Surveillance States

Interesting research: “Characterizing and Avoiding Routing Detours Through Surveillance States,” by Anne Edmundson, Roya Ensafi, Nick Feamster, and Jennifer Rexford.

Abstract: An increasing number of countries are passing laws that facilitate the mass surveillance of Internet traffic. In response, governments and citizens are increasingly paying attention to the countries that their Internet traffic traverses. In some cases, countries are taking extreme steps, such as building new Internet Exchange Points (IXPs), which allow networks to interconnect directly, and encouraging local interconnection to keep local traffic local. We find that although many of these efforts are extensive, they are often futile, due to the inherent lack of hosting and route diversity for many popular sites. By measuring the country-level paths to popular domains, we characterize transnational routing detours. We find that traffic is traversing known surveillance states, even when the traffic originates and ends in a country that does not conduct mass surveillance. Then, we investigate how clients can use overlay network relays and the open DNS resolver infrastructure to prevent their traffic from traversing certain jurisdictions. We find that 84% of paths originating in Brazil traverse the United States, but when relays are used for country avoidance, only 37% of Brazilian paths traverse the United States. Using the open DNS resolver infrastructure allows Kenyan clients to avoid the United States on 17% more paths. Unfortunately, we find that some of the more prominent surveillance states (e.g., the U.S.) are also some of the least avoidable countries.

Posted on July 7, 2016 at 6:47 AMView Comments

How GCHQ Tracks Internet Users

The Intercept has a new story from the Snowden documents about the UK’s surveillance of the Internet by the GCHQ:

The mass surveillance operation ­ code-named KARMA POLICE­ was launched by British spies about seven years ago without any public debate or scrutiny. It was just one part of a giant global Internet spying apparatus built by the United Kingdom’s electronic eavesdropping agency, Government Communications Headquarters, or GCHQ.

[…]

One system builds profiles showing people’s web browsing histories. Another analyzes instant messenger communications, emails, Skype calls, text messages, cell phone locations, and social media interactions. Separate programs were built to keep tabs on “suspicious” Google searches and usage of Google Maps.

[…]

As of March 2009, the largest slice of data Black Hole held — 41 percent — was about people’s Internet browsing histories. The rest included a combination of email and instant messenger records, details about search engine queries, information about social media activity, logs related to hacking operations, and data on people’s use of tools to browse the Internet anonymously.

Lots more in the article. The Intercept also published 28 new top secret NSA and GCHQ documents.

Posted on September 29, 2015 at 6:16 AMView Comments

China's "Great Cannon"

Interesting research: “An Analysis of China’s ‘Great Cannon.’

Abstract: On March 16th, 2015, the Chinese censorship apparatus employed a new tool, the “Great Cannon”, to engineer a denial-of-service attack on GreatFire.org, an organization dedicated to resisting China’s censorship. We present a technical analysis of the attack and what it reveals about the Great Cannon’s working, underscoring that in essence it constitutes a selective nation-state Man-in-the-Middle attack tool. Although sharing some code similarities and network locations with the Great Firewall, the Great Cannon is a distinct tool, designed to compromise foreign visitors to Chinese sites. We identify the Great Cannon’s operational behavior, localize it in the network topology, verify its distinctive side-channel, and attribute the system as likely operated by the Chinese government. We also discuss the substantial policy implications raised by its use, including the potential imposition on any user whose browser might visit (even inadvertently) a Chinese web site.

Posted on September 4, 2015 at 8:16 AMView Comments

More about the NSA's XKEYSCORE

I’ve been reading through the 48 classified documents about the NSA’s XKEYSCORE system released by the Intercept last week. From the article:

The NSA’s XKEYSCORE program, first revealed by The Guardian, sweeps up countless people’s Internet searches, emails, documents, usernames and passwords, and other private communications. XKEYSCORE is fed a constant flow of Internet traffic from fiber optic cables that make up the backbone of the world’s communication network, among other sources, for processing. As of 2008, the surveillance system boasted approximately 150 field sites in the United States, Mexico, Brazil, United Kingdom, Spain, Russia, Nigeria, Somalia, Pakistan, Japan, Australia, as well as many other countries, consisting of over 700 servers.

These servers store “full-take data” at the collection sites — meaning that they captured all of the traffic collected — and, as of 2009, stored content for 3 to 5 days and metadata for 30 to 45 days. NSA documents indicate that tens of billions of records are stored in its database. “It is a fully distributed processing and query system that runs on machines around the world,” an NSA briefing on XKEYSCORE says. “At field sites, XKEYSCORE can run on multiple computers that gives it the ability to scale in both processing power and storage.”

There seems to be no access controls at all restricting how analysts can use XKEYSCORE. Standing queries — called “workflows” — and new fingerprints have an approval process, presumably for load issues, but individual queries are not approved beforehand but may be audited after the fact. These are things which are supposed to be low latency, and you can’t have an approval process for low latency analyst queries. Since a query can get at the recorded raw data, a single query is effectively a retrospective wiretap.

All this means that the Intercept is correct when it writes:

These facts bolster one of Snowden’s most controversial statements, made in his first video interview published by The Guardian on June 9, 2013. “I, sitting at my desk,” said Snowden, could “wiretap anyone, from you or your accountant, to a federal judge to even the president, if I had a personal email.”

You’ll only get the data if it’s in the NSA’s databases, but if it is there you’ll get it.

Honestly, there’s not much in these documents that’s a surprise to anyone who studied the 2013 XKEYSCORE leaks and knows what can be done with a highly customizable Intrusion Detection System. But it’s always interesting to read the details.

One document — “Intro to Context Sensitive Scanning with X-KEYSCORE Fingerprints (2010) — talks about some of the queries an analyst can run. A sample scenario: “I want to look for people using Mojahedeen Secrets encryption from an iPhone” (page 6).

Mujahedeen Secrets is an encryption program written by al Qaeda supporters. It has been around since 2007. Last year, Stuart Baker cited its increased use as evidence that Snowden harmed America. I thought the opposite, that the NSA benefits from al Qaeda using this program. I wrote: “There’s nothing that screams ‘hack me’ more than using specially designed al Qaeda encryption software.”

And now we see how it’s done. In the document, we read about the specific XKEYSCORE queries an analyst can use to search for traffic encrypted by Mujahedeen Secrets. Here are some of the program’s fingerprints (page 10):

encryption/mojahaden2
encryption/mojahaden2/encodedheader
encryption/mojahaden2/hidden
encryption/mojahaden2/hidden2
encryption/mojahaden2/hidden44
encryption/mojahaden2/secure_file_cendode
encryption/mojahaden2/securefile

So if you want to search for all iPhone users of Mujahedeen Secrets (page 33):

fingerprint(‘demo/scenario4’)=

fingerprint(‘encryption/mojahdeen2’ and fingerprint(‘browser/cellphone/iphone’)

Or you can search for the program’s use in the encrypted text, because (page 37): “…many of the CT Targets are now smart enough not to leave the Mojahedeen Secrets header in the E-mails they send. How can we detect that the E-mail (which looks like junk) is in fact Mojahedeen Secrets encrypted text.” Summary of the answer: there are lots of ways to detect the use of this program that users can’t detect. And you can combine the use of Mujahedeen Secrets with other identifiers to find targets. For example, you can specifically search for the program’s use in extremist forums (page 9). (Note that the NSA wrote that comment about Mujahedeen Secrets users increasing their opsec in 2010, two years before Snowden supposedly told them that the NSA was listening on their communications. Honestly, I would not be surprised if the program turned out to have been a US operation to get Islamic radicals to make their traffic stand out more easily.)

It’s not just Mujahedeen Secrets. Nicholas Weaver explains how you can use XKEYSCORE to identify co-conspirators who are all using PGP.

And these searches are just one example. Other examples from the documents include:

  • “Targets using mail.ru from a behind a large Iranian proxy” (here, page 7).
  • Usernames and passwords of people visiting gov.ir (here, page 26 and following).
  • People in Pakistan visiting certain German-language message boards (here, page 1).
  • HTTP POST traffic from Russia in the middle of the night — useful for finding people trying to steal our data (here, page 16).
  • People doing web searches on jihadist topics from Kabul (here).

E-mails, chats, web-browsing traffic, pictures, documents, voice calls, webcam photos, web searches, advertising analytics traffic, social media traffic, botnet traffic, logged keystrokes, file uploads to online services, Skype sessions and more: if you can figure out how to form the query, you can ask XKEYSCORE for it. For an example of how complex the searches can be, look at this XKEYSCORE query published in March, showing how New Zealand used the system to spy on the World Trade Organization: automatically track any email body with any particular WTO-related content for the upcoming election. (Good new documents to read include this, this, and this.)

I always read these NSA documents with an assumption that other countries are doing the same thing. The NSA is not made of magic, and XKEYSCORE is not some super-advanced NSA-only technology. It is the same sort of thing that every other country would use with its surveillance data. For example, Russia explicitly requires ISPs to install similar monitors as part of its SORM Internet surveillance system. As a home user, you can build your own XKEYSCORE using the public-domain Bro Security Monitor and the related Network Time Machine attached to a back-end data-storage system. (Lawrence Berkeley National Laboratory uses this system to store three months’ worth of Internet traffic for retrospective surveillance — it used the data to study Heartbleed.) The primary advantage the NSA has is that it sees more of the Internet than anyone else, and spends more money to store the data it intercepts for longer than anyone else. And if these documents explain XKEYSCORE in 2009 and 2010, expect that it’s much more powerful now.

Back to encryption and Mujahedeen Secrets. If you want to stay secure, whether you’re trying to evade surveillance by Russia, China, the NSA, criminals intercepting large amounts of traffic, or anyone else, try not to stand out. Don’t use some homemade specialized cryptography that can be easily identified by a system like this. Use reasonably strong encryption software on a reasonably secure device. If you trust Apple’s claims (pages 35-6), use iMessage and FaceTime on your iPhone. I really like Moxie Marlinspike’s Signal for both text and voice, but worry that it’s too obvious because it’s still rare. Ubiquitous encryption is the bane of listeners worldwide, and it’s the best thing we can deploy to make the world safer.

Posted on July 7, 2015 at 6:38 AMView Comments

Sidebar photo of Bruce Schneier by Joe MacInnis.