Entries Tagged "DNS"

Page 1 of 4

Microsoft Buys Corp.com

A few months ago, Brian Krebs told the story of the domain corp.com, and how it is basically a security nightmare:

At issue is a problem known as “namespace collision,” a situation where domain names intended to be used exclusively on an internal company network end up overlapping with domains that can resolve normally on the open Internet.

Windows computers on an internal corporate network validate other things on that network using a Microsoft innovation called Active Directory, which is the umbrella term for a broad range of identity-related services in Windows environments. A core part of the way these things find each other involves a Windows feature called “DNS name devolution,” which is a kind of network shorthand that makes it easier to find other computers or servers without having to specify a full, legitimate domain name for those resources.

For instance, if a company runs an internal network with the name internalnetwork.example.com, and an employee on that network wishes to access a shared drive called “drive1,” there’s no need to type “drive1.internalnetwork.example.com” into Windows Explorer; typing “\\drive1\” alone will suffice, and Windows takes care of the rest.

But things can get far trickier with an internal Windows domain that does not map back to a second-level domain the organization actually owns and controls. And unfortunately, in early versions of Windows that supported Active Directory — Windows 2000 Server, for example — the default or example Active Directory path was given as “corp,” and many companies apparently adopted this setting without modifying it to include a domain they controlled.

Compounding things further, some companies then went on to build (and/or assimilate) vast networks of networks on top of this erroneous setting.

Now, none of this was much of a security concern back in the day when it was impractical for employees to lug their bulky desktop computers and monitors outside of the corporate network. But what happens when an employee working at a company with an Active Directory network path called “corp” takes a company laptop to the local Starbucks?

Chances are good that at least some resources on the employee’s laptop will still try to access that internal “corp” domain. And because of the way DNS name devolution works on Windows, that company laptop online via the Starbucks wireless connection is likely to then seek those same resources at “corp.com.”

In practical terms, this means that whoever controls corp.com can passively intercept private communications from hundreds of thousands of computers that end up being taken outside of a corporate environment which uses this “corp” designation for its Active Directory domain.

Microsoft just bought it, so it wouldn’t fall into the hands of any bad actors:

In a written statement, Microsoft said it acquired the domain to protect its customers.

“To help in keeping systems protected we encourage customers to practice safe security habits when planning for internal domain and network names,” the statement reads. “We released a security advisory in June of 2009 and a security update that helps keep customers safe. In our ongoing commitment to customer security, we also acquired the Corp.com domain.”

Posted on April 9, 2020 at 6:45 AMView Comments

Firefox Enables DNS over HTTPS

This is good news:

Whenever you visit a website — even if it’s HTTPS enabled — the DNS query that converts the web address into an IP address that computers can read is usually unencrypted. DNS-over-HTTPS, or DoH, encrypts the request so that it can’t be intercepted or hijacked in order to send a user to a malicious site.


But the move is not without controversy. Last year, an internet industry group branded Mozilla an “internet villain” for pressing ahead the security feature. The trade group claimed it would make it harder to spot terrorist materials and child abuse imagery. But even some in the security community are split, amid warnings that it could make incident response and malware detection more difficult.

The move to enable DoH by default will no doubt face resistance, but browser makers have argued it’s not a technology that browser makers have shied away from. Firefox became the first browser to implement DoH — with others, like Chrome, Edge, and Opera — quickly following suit.

I think DoH is a great idea, and long overdue.

Slashdot thread. Tech details here. And here’s a good summary of the criticisms.

Posted on February 25, 2020 at 9:15 AMView Comments

DNSSEC Keysigning Ceremony Postponed Because of Locked Safe

Interesting collision of real-world and Internet security:

The ceremony sees several trusted internet engineers (a minimum of three and up to seven) from across the world descend on one of two secure locations — one in El Segundo, California, just south of Los Angeles, and the other in Culpeper, Virginia — both in America, every three months.

Once in place, they run through a lengthy series of steps and checks to cryptographically sign the digital key pairs used to secure the internet’s root zone. (Here’s Cloudflare‘s in-depth explanation, and IANA’s PDF step-by-step guide.)


Only specific named people are allowed to take part in the ceremony, and they have to pass through several layers of security — including doors that can only be opened through fingerprint and retinal scans — before getting in the room where the ceremony takes place.

Staff open up two safes, each roughly one-metre across. One contains a hardware security module that contains the private portion of the KSK. The module is activated, allowing the KSK private key to sign keys, using smart cards assigned to the ceremony participants. These credentials are stored in deposit boxes and tamper-proof bags in the second safe. Each step is checked by everyone else, and the event is livestreamed. Once the ceremony is complete — which takes a few hours — all the pieces are separated, sealed, and put back in the safes inside the secure facility, and everyone leaves.

But during what was apparently a check on the system on Tuesday night — the day before the ceremony planned for 1300 PST (2100 UTC) Wednesday — IANA staff discovered that they couldn’t open one of the two safes. One of the locking mechanisms wouldn’t retract and so the safe stayed stubbornly shut.

As soon as they discovered the problem, everyone involved, including those who had flown in for the occasion, were told that the ceremony was being postponed. Thanks to the complexity of the problem — a jammed safe with critical and sensitive equipment inside — they were told it wasn’t going to be possible to hold the ceremony on the back-up date of Thursday, either.

Posted on February 14, 2020 at 6:07 AMView Comments

New DNS Hijacking Attacks

DNS hijacking isn’t new, but this seems to be an attack of unprecedented scale:

Researchers at Cisco’s Talos security division on Wednesday revealed that a hacker group it’s calling Sea Turtle carried out a broad campaign of espionage via DNS hijacking, hitting 40 different organizations. In the process, they went so far as to compromise multiple country-code top-level domains — the suffixes like .co.uk or .ru that end a foreign web address — putting all the traffic of every domain in multiple countries at risk.

The hackers’ victims include telecoms, internet service providers, and domain registrars responsible for implementing the domain name system. But the majority of the victims and the ultimate targets, Cisco believes, were a collection of mostly governmental organizations, including ministries of foreign affairs, intelligence agencies, military targets, and energy-related groups, all based in the Middle East and North Africa. By corrupting the internet’s directory system, hackers were able to silently use “man in the middle” attacks to intercept all internet data from email to web traffic sent to those victim organizations.


Cisco Talos said it couldn’t determine the nationality of the Sea Turtle hackers, and declined to name the specific targets of their spying operations. But it did provide a list of the countries where victims were located: Albania, Armenia, Cyprus, Egypt, Iraq, Jordan, Lebanon, Libya, Syria, Turkey, and the United Arab Emirates. Cisco’s Craig Williams confirmed that Armenia’s .am top-level domain was one of the “handful” that were compromised, but wouldn’t say which of the other countries’ top-level domains were similarly hijacked.

Another news article.

Posted on April 18, 2019 at 5:13 AMView Comments

New DDoS Reflection-Attack Variant

This is worrisome:

DDoS vandals have long intensified their attacks by sending a small number of specially designed data packets to publicly available services. The services then unwittingly respond by sending a much larger number of unwanted packets to a target. The best known vectors for these DDoS amplification attacks are poorly secured domain name system resolution servers, which magnify volumes by as much as 50 fold, and network time protocol, which increases volumes by about 58 times.

On Tuesday, researchers reported attackers are abusing a previously obscure method that delivers attacks 51,000 times their original size, making it by far the biggest amplification method ever used in the wild. The vector this time is memcached, a database caching system for speeding up websites and networks. Over the past week, attackers have started abusing it to deliver DDoSes with volumes of 500 gigabits per second and bigger, DDoS mitigation service Arbor Networks reported in a blog post.

Cloudflare blog post. BoingBoing post.

EDITED TO ADD (3/9): Brian Krebs covered this.

Posted on March 7, 2018 at 6:23 AMView Comments

Regulation of the Internet of Things

Late last month, popular websites like Twitter, Pinterest, Reddit and PayPal went down for most of a day. The distributed denial-of-service attack that caused the outages, and the vulnerabilities that made the attack possible, was as much a failure of market and policy as it was of technology. If we want to secure our increasingly computerized and connected world, we need more government involvement in the security of the “Internet of Things” and increased regulation of what are now critical and life-threatening technologies. It’s no longer a question of if, it’s a question of when.

First, the facts. Those websites went down because their domain name provider — a company named Dyn —­ was forced offline. We don’t know who perpetrated that attack, but it could have easily been a lone hacker. Whoever it was launched a distributed denial-of-service attack against Dyn by exploiting a vulnerability in large numbers ­— possibly millions — of Internet-of-Things devices like webcams and digital video recorders, then recruiting them all into a single botnet. The botnet bombarded Dyn with traffic, so much that it went down. And when it went down, so did dozens of websites.

Your security on the Internet depends on the security of millions of Internet-enabled devices, designed and sold by companies you’ve never heard of to consumers who don’t care about your security.

The technical reason these devices are insecure is complicated, but there is a market failure at work. The Internet of Things is bringing computerization and connectivity to many tens of millions of devices worldwide. These devices will affect every aspect of our lives, because they’re things like cars, home appliances, thermostats, light bulbs, fitness trackers, medical devices, smart streetlights and sidewalk squares. Many of these devices are low-cost, designed and built offshore, then rebranded and resold. The teams building these devices don’t have the security expertise we’ve come to expect from the major computer and smartphone manufacturers, simply because the market won’t stand for the additional costs that would require. These devices don’t get security updates like our more expensive computers, and many don’t even have a way to be patched. And, unlike our computers and phones, they stay around for years and decades.

An additional market failure illustrated by the Dyn attack is that neither the seller nor the buyer of those devices cares about fixing the vulnerability. The owners of those devices don’t care. They wanted a webcam —­ or thermostat, or refrigerator ­— with nice features at a good price. Even after they were recruited into this botnet, they still work fine ­— you can’t even tell they were used in the attack. The sellers of those devices don’t care: They’ve already moved on to selling newer and better models. There is no market solution because the insecurity primarily affects other people. It’s a form of invisible pollution.

And, like pollution, the only solution is to regulate. The government could impose minimum security standards on IoT manufacturers, forcing them to make their devices secure even though their customers don’t care. They could impose liabilities on manufacturers, allowing companies like Dyn to sue them if their devices are used in DDoS attacks. The details would need to be carefully scoped, but either of these options would raise the cost of insecurity and give companies incentives to spend money making their devices secure.

It’s true that this is a domestic solution to an international problem and that there’s no U.S. regulation that will affect, say, an Asian-made product sold in South America, even though that product could still be used to take down U.S. websites. But the main costs in making software come from development. If the United States and perhaps a few other major markets implement strong Internet-security regulations on IoT devices, manufacturers will be forced to upgrade their security if they want to sell to those markets. And any improvements they make in their software will be available in their products wherever they are sold, simply because it makes no sense to maintain two different versions of the software. This is truly an area where the actions of a few countries can drive worldwide change.

Regardless of what you think about regulation vs. market solutions, I believe there is no choice. Governments will get involved in the IoT, because the risks are too great and the stakes are too high. Computers are now able to affect our world in a direct and physical manner.

Security researchers have demonstrated the ability to remotely take control of Internet-enabled cars. They’ve demonstrated ransomware against home thermostats and exposed vulnerabilities in implanted medical devices. They’ve hacked voting machines and power plants. In one recent paper, researchers showed how a vulnerability in smart light bulbs could be used to start a chain reaction, resulting in them all being controlled by the attackers ­— that’s every one in a city. Security flaws in these things could mean people dying and property being destroyed.

Nothing motivates the U.S. government like fear. Remember 2001? A small-government Republican president created the Department of Homeland Security in the wake of the 9/11 terrorist attacks: a rushed and ill-thought-out decision that we’ve been trying to fix for more than a decade. A fatal IoT disaster will similarly spur our government into action, and it’s unlikely to be well-considered and thoughtful action. Our choice isn’t between government involvement and no government involvement. Our choice is between smarter government involvement and stupider government involvement. We have to start thinking about this now. Regulations are necessary, important and complex ­— and they’re coming. We can’t afford to ignore these issues until it’s too late.

In general, the software market demands that products be fast and cheap and that security be a secondary consideration. That was okay when software didn’t matter —­ it was okay that your spreadsheet crashed once in a while. But a software bug that literally crashes your car is another thing altogether. The security vulnerabilities in the Internet of Things are deep and pervasive, and they won’t get fixed if the market is left to sort it out for itself. We need to proactively discuss good regulatory solutions; otherwise, a disaster will impose bad ones on us.

This essay previously appeared in the Washington Post.

Posted on November 10, 2016 at 6:06 AMView Comments

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

Yet Another Government-Sponsored Malware

Both Kaspersky and Symantec have uncovered another piece of malware that seems to be a government design:

The malware — known alternatively as “ProjectSauron” by researchers from Kaspersky Lab and “Remsec” by their counterparts from Symantec — has been active since at least 2011 and has been discovered on 30 or so targets. Its ability to operate undetected for five years is a testament to its creators, who clearly studied other state-sponsored hacking groups in an attempt to replicate their advances and avoid their mistakes.


Part of what makes ProjectSauron so impressive is its ability to collect data from computers considered so sensitive by their operators that they have no Internet connection. To do this, the malware uses specially prepared USB storage drives that have a virtual file system that isn’t viewable by the Windows operating system. To infected computers, the removable drives appear to be approved devices, but behind the scenes are several hundred megabytes reserved for storing data that is kept on the “air-gapped” machines. The arrangement works even against computers in which data-loss prevention software blocks the use of unknown USB drives.

Kaspersky researchers still aren’t sure precisely how the USB-enabled exfiltration works. The presence of the invisible storage area doesn’t in itself allow attackers to seize control of air-gapped computers. The researchers suspect the capability is used only in rare cases and requires use of a zero-day exploit that has yet to be discovered. In all, Project Sauron is made up of at least 50 modules that can be mixed and matched to suit the objectives of each individual infection.

“Once installed, the main Project Sauron modules start working as ‘sleeper cells,’ displaying no activity of their own and waiting for ‘wake-up’ commands in the incoming network traffic,” Kaspersky researchers wrote in a separate blog post. “This method of operation ensures Project Sauron’s extended persistence on the servers of targeted organizations.”

We don’t know who designed this, but it certainly seems likely to be a country with a serious cyberespionage budget.

EDITED TO ADD (8/15): Nicholas Weaver comment on the malware and what it means.

Posted on August 15, 2016 at 1:43 PMView Comments

1 2 3 4

Sidebar photo of Bruce Schneier by Joe MacInnis.