Month: June 2018

HOW CREATIVE DDOS ATTACKS STILL SLIP PAST DEFENSES

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Originally Seen: March 12, 2018 on Wired.

DISTRIBUTED DENIAL OF service attacks, in which hackers use a targeted hose of junk traffic to overwhelm a service or take a server offline, have been a digital menace for decades. But in just the last 18 months, the public picture of DDoS defense has evolved rapidly. In fall 2016, a rash of then-unprecedented attacks caused internet outages and other service disruptions at a series of internet infrastructure and telecom companies around the world. Those attacks walloped their victims with floods of malicious data measured up to 1.2 Tbps. And they gave the impression that massive, “volumetric” DDOS attacks can be nearly impossible to defend against.

The past couple of weeks have presented a very different view of the situation, though. On March 1, Akamai defended developer platform GitHub against a 1.3 Tbps attack. And early last week, a DDOS campaign against an unidentified service in the United States topped out at a staggering 1.7 Tbps, according to the network security firm Arbor Networks. Which means that for the first time, the web sits squarely in the “terabit attack era,” as Arbor Networks put it. And yet, the internet hasn’t collapsed.

One might even get the impression from recent high-profile successes that DDoS is a solved problem. Unfortunately, network defenders and internet infrastructure experts emphasize that despite the positive outcomes, DDoS continues to pose a serious threat. And sheer volume isn’t the only danger. Ultimately, anything that causes disruption and affects service availability by diverting a digital system’s resources or overloading its capacity can be seen as a DDoS attack. Under that conceptual umbrella, attackers can generate a diverse array of lethal campaigns.

“DDoS will never be over as a threat, sadly,” says Roland Dobbins, a principal engineer at Arbor Networks. “We see thousands of DDoS attacks per day—millions per year. There are major concerns.”

Getting Clever

One example of a creative interpretation of a DDoS is the attack Netflix researchers tried out against the streaming service itself in 2016. It works by targeting Netflix’s application programming interface with carefully tailored requests. These queries are built to start a cascade within the middle and backend application layers the streaming service is built on—demanding more and more system resources as they echo through the infrastructure. That type of DDoS only requires attackers to send out a small amount of malicious data, so mounting the offensive would be cheap and efficient, but clever execution could cause internal disruptions or a total meltdown.

“What creates the nightmare situations are the smaller attacks that overwork applications, firewalls, and load balancers,” says Barrett Lyon, head of research and development at Neustar Security Solutions. “The big attacks are sensational, but it’s the well-crafted connection floods that have the most success.”

‘We see thousands of DDoS attacks per day—millions per year.’

ROLAND DOBBINS, ARBOR NETWORKS

These types of attacks target specific protocols or defenses as a way of efficiently undermining broader services. Overwhelming the server that manages firewall connections, for example, can allow attackers to access a private network. Similarly, deluging a system’s load balancers—devices that manage a network’s computing resources to improve speed and efficiency—can cause backups and overloads. These types of attacks are “as common as breathing,” as Dobbins puts it, because they take advantage of small disruptions that can have a big impact on an organization’s defenses.

Similarly, an attacker looking to disrupt connectivity on the internet in general can target the exposed protocols that coordinate and manage data flow around the web, rather than trying to take on more robust components.

That’s what happened last fall to Dyn, an internet infrastructure company that offers Domain Name System services (essentially the address book routing structure of the internet). By DDoSing Dyn and destabilizing the company’s DNS servers, attackers caused outages by disrupting the mechanism browsers use to look up websites. “The most frequently attacked targets for denial of service is web severs and DNS servers,” says Dan Massey, chief scientist at the DNS security firm Secure64 who formerly worked on DDoS defense research at the Department of Homeland Security. “But there are also so many variations on and so many components of denial of service attacks. There’s no such thing as one-size-fits-all defense.”

Memcached and Beyond

The type of DDoS attack hackers have been using recently to mount enormous attacks is somewhat similar. Known as memcached DDoS, these attacks take advantage of unprotected network management servers that aren’t meant to be exposed on the internet. And they capitalize on the fact that they can send a tiny customized packet to a memcached server, and elicit a much larger response in return. So a hacker can query thousands of vulnerable memcached servers multiple times per second each, and direct the much larger responses toward a target.

This approach is easier and cheaper for attackers than generating the traffic needed for large-scale volumetric attacks using a botnet—the platforms typically used to power DDoS assaults. The memorable 2016 attacks were famously driven by the so-called “Mirai” botnet. Mirai infected 600,000 unassuming Internet of Things products, like webcams and routers, with malware that hackers could use to control the devices and coordinate them to produce massive attacks. And though attackers continued to refine and advance the malware—and still use Mirai-variant botnets in attacks to this day—it was difficult to maintain the power of the original attacks as more hackers jockeyed for control of the infected device population, and it splintered into numerous smaller botnets.

‘There’s no such thing as one-size-fits-all defense.’

DAN MASSEY, SECURE64

While effective, building and maintaining botnets requires resources and effort, whereas exploiting memcached servers is easy and almost free. But the tradeoff for attackers is that memcached DDOS is more straightforward to defend against if security and infrastructure firms have enough bandwidth. So far, the high-profile memcached targets have all been defended by services with adequate resources. In the wake of the 2016 attacks, foreseeing that volumetric assaults would likely continue to grow, defenders seriously expanded their available capacity.

As an added twist, DDoS attacks have also increasingly incorporated ransom requests as part of hackers’ strategies. This has especially been the case with memcached DDoS. “It’s an attack of opportunity,” says Chad Seaman, a senior engineer on the security intelligence response team at Akamai. “Why not try and extort and maybe trick someone into paying it?”

The DDoS defense and internet infrastructure industries have made significant progress on DDoS mitigation, partly through increased collaboration and information-sharing. But with so much going on, the crucial point is that DDoS defense is still an active challenge for defenders every day. “

When sites continue to work it doesn’t mean it’s easy or the problem is gone.” Neustar’s Lyon says. “It’s been a long week.”

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Look-Alike Domains and Visual Confusion

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Originally Seen: March 8th, 2018 on krebsonsecurity.

How good are you at telling the difference between domain names you know and trust and impostor or look-alike domains? The answer may depend on how familiar you are with the nuances of internationalized domain names (IDNs), as well as which browser or Web application you’re using.

For example, how does your browser interpret the following domain? I’ll give you a hint: Despite appearances, it is most certainly not the actual domain for software firm CA Technologies (formerly Computer Associates Intl Inc.), which owns the original ca.com domain name:

https://www.са.com/

Go ahead and click on the link above or cut-and-paste it into a browser address bar. If you’re using Google ChromeApple’s Safari, or some recent version of Microsoft‘s Internet Explorer or Edge browsers, you should notice that the address converts to “xn--80a7a.com.” This is called “punycode,” and it allows browsers to render domains with non-Latin alphabets like Cyrillic and Ukrainian.

Below is what it looks like in Edge on Windows 10; Google Chrome renders it much the same way. Notice what’s in the address bar (ignore the “fake site” and “Welcome to…” text, which was added as a courtesy by the person who registered this domain):

IE, Edge, Chrome and Safari all will convert https://www.са.com/ into its punycode output (xn--80a7a.com), in part to warn visitors about any confusion over look-alike domains registered in other languages. But if you load that domain in Mozilla Firefox and look at the address bar, you’ll notice there’s no warning of possible danger ahead. It just looks like it’s loading the real ca.com:

The domain “xn--80a7a.com” pictured in the first screenshot above is punycode for the Ukrainian letters for “s” (which is represented by the character “c” in Russian and Ukrainian), as well as an identical Ukrainian “a”.

It was registered by Alex Holden, founder of Milwaukee, Wis.-based Hold Security Inc.Holden’s been experimenting with how the different browsers handle punycodes in the browser and via email. Holden grew up in what was then the Soviet Union and speaks both Russian and Ukrainian, and he’s been playing with Cyrillic letters to spell English words in domain names.

Letters like A and O look exactly the same and the only difference is their Unicode value. There are more than 136,000 Unicode characters used to represent letters and symbols in 139 modern and historic scripts, so there’s a ton of room for look-alike or malicious/fake domains.

For example, “a” in Latin is the Unicode value “0061” and in Cyrillic is “0430.”  To a human, the graphical representation for both looks the same, but for a computer there is a huge difference. Internationalized domain names (IDNs) allow domain names to be registered in non-Latin letters (RFC 3492), provided the domain is all in the same language; trying to mix two different IDNs in the same name causes the domain registries to reject the registration attempt.

So, in the Cyrillic alphabet (Russian/Ukrainian), we can spell АТТ, УАНОО, ХВОХ, and so on. As you can imagine, the potential opportunity for impersonation and abuse are great with IDNs. Here’s a snippet from a larger chart Holden put together showing some of the more common ways that IDNs can be made to look like established, recognizable domains:

Holden also was able to register a valid SSL encryption certificate for https://www.са.com from Comodo.com, which would only add legitimacy to the domain were it to be used in phishing attacks against CA customers by bad guys, for example.

A SOLUTION TO VISUAL CONFUSION

To be clear, the potential threat highlighted by Holden’s experiment is not new. Security researchers have long warned about the use of look-alike domains that abuse special IDN/Unicode characters. Most of the major browser makers have responded in some way by making their browsers warn users about potential punycode look-alikes.

With the exception of Mozilla, which by most accounts is the third most-popular Web browser. And I wanted to know why. I’d read the Mozilla Wiki’s IDN Display Algorithm FAQ,” so I had an idea of what Mozilla was driving at in their decision not to warn Firefox users about punycode domains: Nobody wanted it to look like Mozilla was somehow treating the non-Western world as second-class citizens.

I wondered why Mozilla doesn’t just have Firefox alert users about punycode domains unless the user has already specified that he or she wants a non-English language keyboard installed. So I asked that in some questions I sent to their media team. They sent the following short statement in reply:

“Visual confusion attacks are not new and are difficult to address while still ensuring that we render everyone’s domain name correctly. We have solved almost all IDN spoofing problems by implementing script mixing restrictions, and we also make use of Safe Browsing technology to protect against phishing attacks. While we continue to investigate better ways to protect our users, we ultimately believe domain name registries are in the best position to address this problem because they have all the necessary information to identify these potential spoofing attacks.”

If you’re a Firefox user and would like Firefox to always render IDNs as their punycode equivalent when displayed in the browser address bar, type “about:config” without the quotes into a Firefox address bar. Then in the “search:” box type “punycode,” and you should see one or two options there. The one you want is called “network.IDN_show_punycode.” By default, it is set to “false”; double-clicking that entry should change that setting to “true.”

Incidentally, anyone using the Tor Browser to anonymize their surfing online is exposed to IDN spoofing because Tor by default uses Mozilla as well. I could definitely see spoofed IDNs being used in targeting phishing attacks aimed at Tor users, many of whom have significant assets tied up in virtual currencies. Fortunately, the same “about:config” instructions work just as well on Tor to display punycode in lieu of IDNs.

Holden said he’s still in the process of testing how various email clients and Web services handle look-alike IDNs. For example, it’s clear that Twitter sees nothing wrong with sending the look-alike CA.com domain in messages to other users without any context or notice. Skype, on the other hand, seems to truncate the IDN link, sending clickers to a non-existent page.

“I’d say that most email services and clients are either vulnerable or not fully protected,” Holden said.

For a look at how phishers or other scammers might use IDNs to abuse your domain name, check out this domain checker that Hold Security developed. Here’s the first page of results for krebsonsecurity.com, which indicate that someone at one point registered krebsoṇsecurity[dot]com (that domain includes a lowercase “n” with a tiny dot below it, a character used by several dozen scripts). The results in yellow are just possible (unregistered) domains based on common look-alike IDN characters.

I wrote this post mainly because I wanted to learn more about the potential phishing and malware threat from look-alike domains, and I hope the information here has been interesting if not also useful. I don’t think this kind of phishing is a terribly pressing threat (especially given how far less complex phishing attacks seem to succeed just fine for now). But it sure can’t hurt Firefox users to change the default “visual confusion” behavior of the browser so that it always displays punycode in the address bar (see the solution mentioned above).

The security concerns of cloud cryptomining services

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Originally seen on: TechTarget

Cloud cryptomining as a service is a security risk to users. Expert Frank Siemons discusses cloud mining service providers and what to look out for if you use one.

One of the more interesting news stories over the last year has been the rise — and, currently, the fall of cryptocurrencies.

Bitcoin is the best-known variety, but other cryptocurrencies, such as Litecoin, Ripple and Ethereum, also saw dramatic increases in their worth during 2017. While some of this value dropped off in the first few weeks of 2018, there exists significant value in these currencies.

These virtual coins or their transactions can be mined for a fee, though some coin varieties are more profitable than others. Bitcoin, for instance, has passed the stage where mining at home returns a profit. The complexity and the mining workload have increased so much that the generated electricity costs far outweigh the value of the mined coins.

To avoid individual initial setup costs and to benefit from some of the efficiency increases that large specialized clusters bring, prospective miners can sign up with a cloud mining service provider.

Cloud mining service providers

The main benefit cloud cryptomining providers offer is their economy of scale. Primarily, these providers operate large data centers filled with specialized mining rigs. Everything from purpose-built hardware and software to power consumption is built around gaining maximum efficiency for cryptomining operations.

This significant investment has already been made, and the customer rents a small part of the processing power — expressed in mega or giga hashes per second — based on their expectancy that the currency will be at a certain price point during the rental period.

Security concerns for cloud cryptomining

The mined virtual coins need to be stored in a digital wallet eventually. Home miners are advised to store this wallet on an encrypted offline medium, such as a detachable USB drive, or to use a secure online digital wallet service.

However, both options carry the risk of losing the stored cryptocurrency. This could be due to the theft or loss of the USB drive, a compromised computer, or a hack or bug within a digital wallet service, for instance.

A cloud cryptomining provider is not bound by the same regulations as a traditional bank. This lack of regulation brings with it significant risk. The providers potentially hold a significant amount of value in the form of virtual money, which makes them an attractive target for cybercriminals.

Some research into where data centers are located and under which jurisdiction they fall is fundamental. After all, technically these data centers could hold a significant investment in their virtual vault. Even physical security is an essential factor to consider.

Because cloud cryptomining services depend on distributed networks and require access to the internet, fully air-gapped storage is not possible in a cloud system. This opens up an entry point for external attackers, which is what the NiceHash hackers exploited when they stole an estimated $64 million worth of bitcoin in 2017.

The attackers gained access to a corporate machine through an engineer’s VPN account and started making transactions via NiceHash’s payment system. This simply could not have happened if an offline wallet was used, as is often the case in smaller, individual setups.

Of course, attacks do not need to come from the outside. When relying on a company that is located in another country, the risk of internal fraud is high because it is handling a large amount of money without the protection of banking regulations. Several cases have been reported where either a staff member ran off with a significant amount of virtual currency or the entire cloud mining company was based on a scam.

Several provider comparison sites exist that discuss the reputations of cloud cryptomining companies. It is also advised to check online forums and social media channels before committing to any investment. Research is critical.

Conclusion

Where there is money, there is crime. The substantial increase in cryptocurrency investments and their meteoric rise in value over the recent months have paved the way for many scams and breaches that are traditionally linked to banks and investment schemes.

Does this mean cloud cryptomining is always unsafe? It does not, but it is essential to look at the providers with at least the same amount of scrutiny as one would use when looking at a more traditional investment firm.

Probably even more scrutiny should be applied because of the lack of proper regulation at this point. As always, technology has outpaced policy.

 

Google Bans Cryptocurrency-Related Ads

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Originally seen on: Bleepingcomputer.com

Google has decided to follow on Facebook’s footsteps and ban cryptocurrency-related advertising. The ban will enter into effect starting June 2018, the company said today in a help page.

In June 2018, Google will update the Financial services policy to restrict the advertisement of Contracts for Difference, rolling spot forex, and financial spread betting. In addition, ads for the following will no longer be allowed to serve:
‧  Binary options and synonymous products
‧  Cryptocurrencies and related content (including but not limited to initial coin offerings, cryptocurrency exchanges, cryptocurrency wallets, and cryptocurrency trading advice)

The ban will enter into effect across all of Google’s advertising network, including ads shown in search results, on third-party websites, and YouTube.

Some ads will be allowed, but not many

But the ban is not total. Google said that certain entities will be able to advertise a limited set of the banned services, including “cryptocurrencies and related content.”

These advertisers will need to apply for certification with Google. The downside is that the “Google certification process” will only be available for advertisers located in “certain countries.”

Google did not provide a list of countries, but said the advertisers will have to be licensed by relevant financial services and “comply with relevant legal requirements, including those related to complex speculative financial products.”

Prices for almost all cryptocurrencies fell across the board today after Google’s announcement, and most coins continued to lose value.

 

Scams and phishing sites to blame

While Google did not provide a backdrop to the reasons it banned cryptocurrency ads, they are likely to be the same to the ones cited by Facebook —misleading ads being abused to drive traffic to financial scams and phishing sites.

There’s been a surge in malware and phishing campaigns targeting cryptocurrency owners ever since Bitcoin price surged in December 2016 [12]. Just last month, Cisco Talos and Ukrainian police disrupted a cybercriminal operation that made over $50 million by using Google ads to to drive traffic to phishing sites.

Malicious ads for cryptocurrencies
Malicious ads for cryptocurrencies

 

report published by “Big Four” accounting firm Ernst & Young in December 2017 reveals that 10% of all ICO (Initial Coin Offering) funds were lost to hackers and scams, and cryptocurrency phishing sites made around $1.5 million per month. The company says that cryptocurrency hacks and scams are a big business, and estimates that crooks made over $2 billion by targeting cryptocoin fans in the past years.

Furthermore, a Bitcoin.com survey revealed that nearly half of 2017’s cryptocurrencies had already failed.

The recent trend of using the overhyped cryptocurrency market and ICOs for financial scams is also the reason why the US Securities and Exchange Commission (SEC) has started investigating and charging people involved in these practices.

This constant abuse of the cryptocurrency theme was the main reason why Facebook banned such ads on its platform, and is, most likely, the reason why Google is getting ready to implement a similar ban in June.