Entries Tagged "patching"

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Spectre and Meltdown Attacks

After a week or so of rumors, everyone is now reporting about the Spectre and Meltdown attacks against pretty much every modern processor out there.

These are side-channel attacks where one process can spy on other processes. They affect computers where an untrusted browser window can execute code, phones that have multiple apps running at the same time, and cloud computing networks that run lots of different processes at once. Fixing them either requires a patch that results in a major performance hit, or is impossible and requires a re-architecture of conditional execution in future CPU chips.

I’ll be writing something for publication over the next few days. This post is basically just a link repository.

EDITED TO ADD: Good technical explanation. And a Slashdot thread.

EDITED TO ADD (1/5): Another good technical description. And how the exploits work through browsers. A rundown of what vendors are doing. Nicholas Weaver on its effects on individual computers.

EDITED TO ADD (1/7): xkcd.

EDITED TO ADD (1/10): Another good technical description.

Posted on January 4, 2018 at 6:28 AMView Comments

Vulnerability in Amazon Key

Amazon Key is an IoT door lock that can enable one-time access codes for delivery people. To further secure that system, Amazon sells Cloud Cam, a camera that watches the door to ensure that delivery people don’t abuse their one-time access privilege.

Cloud Cam has been hacked:

But now security researchers have demonstrated that with a simple program run from any computer in Wi-Fi range, that camera can be not only disabled but frozen. A viewer watching its live or recorded stream sees only a closed door, even as their actual door is opened and someone slips inside. That attack would potentially enable rogue delivery people to stealthily steal from Amazon customers, or otherwise invade their inner sanctum.

And while the threat of a camera-hacking courier seems an unlikely way for your house to be burgled, the researchers argue it potentially strips away a key safeguard in Amazon’s security system.

Amazon is patching the system.

Posted on November 20, 2017 at 6:19 AMView Comments

Bluetooth Vulnerabilities

A bunch of Bluetooth vulnerabilities are being reported, some pretty nasty.

BlueBorne concerns us because of the medium by which it operates. Unlike the majority of attacks today, which rely on the internet, a BlueBorne attack spreads through the air. This works similarly to the two less extensive vulnerabilities discovered recently in a Broadcom Wi-Fi chip by Project Zero and Exodus. The vulnerabilities found in Wi-Fi chips affect only the peripherals of the device, and require another step to take control of the device. With BlueBorne, attackers can gain full control right from the start. Moreover, Bluetooth offers a wider attacker surface than WiFi, almost entirely unexplored by the research community and hence contains far more vulnerabilities.

Airborne attacks, unfortunately, provide a number of opportunities for the attacker. First, spreading through the air renders the attack much more contagious, and allows it to spread with minimum effort. Second, it allows the attack to bypass current security measures and remain undetected, as traditional methods do not protect from airborne threats. Airborne attacks can also allow hackers to penetrate secure internal networks which are “air gapped,” meaning they are disconnected from any other network for protection. This can endanger industrial systems, government agencies, and critical infrastructure.

Finally, unlike traditional malware or attacks, the user does not have to click on a link or download a questionable file. No action by the user is necessary to enable the attack.

Fully patched Windows and iOS systems are protected; Linux coming soon.

Posted on September 18, 2017 at 6:58 AMView Comments

More on the Vulnerabilities Equities Process

Richard Ledgett—a former Deputy Director of the NSA—argues against the US government disclosing all vulnerabilities:

Proponents argue that this would allow patches to be developed, which in turn would help ensure that networks are secure. On its face, this argument might seem to make sense—but it is a gross oversimplification of the problem, one that not only would not have the desired effect but that also would be dangerous.

Actually, he doesn’t make that argument at all. He basically says that security is a lot more complicated than finding and disclosing vulnerabilities—something I don’t think anyone disagrees with. His conclusion:

Malicious software like WannaCry and Petya is a scourge in our digital lives, and we need to take concerted action to protect ourselves. That action must be grounded in an accurate understanding of how the vulnerability ecosystem works. Software vendors need to continue working to build better software and to provide patching support for software deployed in critical infrastructure. Customers need to budget and plan for upgrades as part of the going-in cost of IT, or for compensatory measures when upgrades are impossible. Those who discover vulnerabilities need to responsibly disclose them or, if they are retained for national security purposes, adequately safeguard them. And the partnership of intelligence, law enforcement and industry needs to work together to identify and disrupt actors who use these vulnerabilities for their criminal and destructive ends. No single set of actions will solve the problem; we must work together to protect ourselves. As for blame, we should place it where it really lies: on the criminals who intentionally and maliciously assembled this destructive ransomware and released it on the world.

I don’t think anyone would argue with any of that, either. The question is whether the US government should prioritize attack over defense, and security over surveillance. Disclosing, especially in a world where the secrecy of zero-day vulnerabilities is so fragile, greatly improves the security of our critical systems.

Posted on August 9, 2017 at 6:40 AMView Comments

Measuring Vulnerability Rediscovery

New paper: “Taking Stock: Estimating Vulnerability Rediscovery,” by Trey Herr, Bruce Schneier, and Christopher Morris:

Abstract: How often do multiple, independent, parties discover the same vulnerability? There are ample models of vulnerability discovery, but little academic work on this issue of rediscovery. The immature state of this research and subsequent debate is a problem for the policy community, where the government’s decision to disclose a given vulnerability hinges in part on that vulnerability’s likelihood of being discovered and used maliciously by another party. Research into the behavior of malicious software markets and the efficacy of bug bounty programs would similarly benefit from an accurate baseline estimate for how often vulnerabilities are discovered by multiple independent parties.

This paper presents a new dataset of more than 4,300 vulnerabilities, and estimates vulnerability rediscovery across different vendors and software types. It concludes that rediscovery happens more than twice as often as the 1-9% range previously reported. For our dataset, 15% to 20% of vulnerabilities are discovered independently at least twice within a year. For just Android, 13.9% of vulnerabilities are rediscovered within 60 days, rising to 20% within 90 days, and above 21% within 120 days. For the Chrome browser we found 12.57% rediscovery within 60 days; and the aggregate rate for our entire dataset generally rises over the eight-year span, topping out at 19.6% in 2016. We believe that the actual rate is even higher for certain types of software.

When combined with an estimate of the total count of vulnerabilities in use by the NSA, these rates suggest that rediscovery of vulnerabilities kept secret by the U.S. government may be the source of up to one-third of all zero-day vulnerabilities detected in use each year. These results indicate that the information security community needs to map the impact of rediscovery on the efficacy of bug bounty programs and policymakers should more rigorously evaluate the costs of non-disclosure of software vulnerabilities.

We wrote a blog post on the paper, and another when we issued a revised version.

Comments on the original paper by Dave Aitel. News articles.

Posted on July 31, 2017 at 5:59 AMView Comments

Zero-Day Vulnerabilities against Windows in the NSA Tools Released by the Shadow Brokers

In April, the Shadow Brokers—presumably Russia—released a batch of Windows exploits from what is presumably the NSA. Included in that release were eight different Windows vulnerabilities. Given a presumed theft date of the data as sometime between 2012 and 2013—based on timestamps of the documents and the limited Windows 8 support of the tools:

  • Three were already patched by Microsoft. That is, they were not zero days, and could only be used against unpatched targets. They are EMERALDTHREAD, EDUCATEDSCHOLAR, and ECLIPSEDWING.
  • One was discovered to have been used in the wild and patched in 2014: ESKIMOROLL.
  • Four were only patched when the NSA informed Microsoft about them in early 2017: ETERNALBLUE, ETERNALSYNERGY, ETERNALROMANCE, and ETERNALCHAMPION.

So of the five serious zero-day vulnerabilities against Windows in the NSA’s pocket, four were never independently discovered. This isn’t new news, but I haven’t seen this summary before.

Posted on July 28, 2017 at 6:16 AMView Comments

Good Article About Google's Project Zero

Fortune magazine just published a good article about Google’s Project Zero, which finds and publishes exploits in other companies’ software products.

I have mixed feeling about it. The project does great work, and the Internet has benefited enormously from these efforts. But as long as it is embedded inside Google, it has to deal with accusations that it targets Google competitors.

Posted on June 30, 2017 at 6:05 AMView Comments

Is Continuing to Patch Windows XP a Mistake?

Last week, Microsoft issued a security patch for Windows XP, a 16-year-old operating system that Microsoft officially no longer supports. Last month, Microsoft issued a Windows XP patch for the vulnerability used in WannaCry.

Is this a good idea? This 2014 essay argues that it’s not:

The zero-day flaw and its exploitation is unfortunate, and Microsoft is likely smarting from government calls for people to stop using Internet Explorer. The company had three ways it could respond. It could have done nothing­—stuck to its guns, maintained that the end of support means the end of support, and encouraged people to move to a different platform. It could also have relented entirely, extended Windows XP’s support life cycle for another few years and waited for attrition to shrink Windows XP’s userbase to irrelevant levels. Or it could have claimed that this case is somehow “special,” releasing a patch while still claiming that Windows XP isn’t supported.

None of these options is perfect. A hard-line approach to the end-of-life means that there are people being exploited that Microsoft refuses to help. A complete about-turn means that Windows XP will take even longer to flush out of the market, making it a continued headache for developers and administrators alike.

But the option Microsoft took is the worst of all worlds. It undermines efforts by IT staff to ditch the ancient operating system and undermines Microsoft’s assertion that Windows XP isn’t supported, while doing nothing to meaningfully improve the security of Windows XP users. The upside? It buys those users at best a few extra days of improved security. It’s hard to say how that was possibly worth it.

This is a hard trade-off, and it’s going to get much worse with the Internet of Things. Here’s me:

The security of our computers and phones also comes from the fact that we replace them regularly. We buy new laptops every few years. We get new phones even more frequently. This isn’t true for all of the embedded IoT systems. They last for years, even decades. We might buy a new DVR every five or ten years. We replace our refrigerator every 25 years. We replace our thermostat approximately never. Already the banking industry is dealing with the security problems of Windows 95 embedded in ATMs. This same problem is going to occur all over the Internet of Things.

At least Microsoft has security engineers on staff that can write a patch for Windows XP. There will be no one able to write patches for your 16-year-old thermostat and refrigerator, even assuming those devices can accept security patches.

Posted on June 21, 2017 at 1:58 PMView Comments

WannaCry and Vulnerabilities

There is plenty of blame to go around for the WannaCry ransomware that spread throughout the Internet earlier this month, disrupting work at hospitals, factories, businesses, and universities. First, there are the writers of the malicious software, which blocks victims’ access to their computers until they pay a fee. Then there are the users who didn’t install the Windows security patch that would have prevented an attack. A small portion of the blame falls on Microsoft, which wrote the insecure code in the first place. One could certainly condemn the Shadow Brokers, a group of hackers with links to Russia who stole and published the National Security Agency attack tools that included the exploit code used in the ransomware. But before all of this, there was the NSA, which found the vulnerability years ago and decided to exploit it rather than disclose it.

All software contains bugs or errors in the code. Some of these bugs have security implications, granting an attacker unauthorized access to or control of a computer. These vulnerabilities are rampant in the software we all use. A piece of software as large and complex as Microsoft Windows will contain hundreds of them, maybe more. These vulnerabilities have obvious criminal uses that can be neutralized if patched. Modern software is patched all the time—either on a fixed schedule, such as once a month with Microsoft, or whenever required, as with the Chrome browser.

When the US government discovers a vulnerability in a piece of software, however, it decides between two competing equities. It can keep it secret and use it offensively, to gather foreign intelligence, help execute search warrants, or deliver malware. Or it can alert the software vendor and see that the vulnerability is patched, protecting the country—and, for that matter, the world—from similar attacks by foreign governments and cybercriminals. It’s an either-or choice. As former US Assistant Attorney General Jack Goldsmith has said, “Every offensive weapon is a (potential) chink in our defense—and vice versa.”

This is all well-trod ground, and in 2010 the US government put in place an interagency Vulnerabilities Equities Process (VEP) to help balance the trade-off. The details are largely secret, but a 2014 blog post by then President Barack Obama’s cybersecurity coordinator, Michael Daniel, laid out the criteria that the government uses to decide when to keep a software flaw undisclosed. The post’s contents were unsurprising, listing questions such as “How much is the vulnerable system used in the core Internet infrastructure, in other critical infrastructure systems, in the US economy, and/or in national security systems?” and “Does the vulnerability, if left unpatched, impose significant risk?” They were balanced by questions like “How badly do we need the intelligence we think we can get from exploiting the vulnerability?” Elsewhere, Daniel has noted that the US government discloses to vendors the “overwhelming majority” of the vulnerabilities that it discovers—91 percent, according to NSA Director Michael S. Rogers.

The particular vulnerability in WannaCry is code-named EternalBlue, and it was discovered by the US government—most likely the NSA—sometime before 2014. The Washington Post reported both how useful the bug was for attack and how much the NSA worried about it being used by others. It was a reasonable concern: many of our national security and critical infrastructure systems contain the vulnerable software, which imposed significant risk if left unpatched. And yet it was left unpatched.

There’s a lot we don’t know about the VEP. The Washington Post says that the NSA used EternalBlue “for more than five years,” which implies that it was discovered after the 2010 process was put in place. It’s not clear if all vulnerabilities are given such consideration, or if bugs are periodically reviewed to determine if they should be disclosed. That said, any VEP that allows something as dangerous as EternalBlue—or the Cisco vulnerabilities that the Shadow Brokers leaked last August to remain unpatched for years isn’t serving national security very well. As a former NSA employee said, the quality of intelligence that could be gathered was “unreal.” But so was the potential damage. The NSA must avoid hoarding vulnerabilities.

Perhaps the NSA thought that no one else would discover EternalBlue. That’s another one of Daniel’s criteria: “How likely is it that someone else will discover the vulnerability?” This is often referred to as NOBUS, short for “nobody but us.” Can the NSA discover vulnerabilities that no one else will? Or are vulnerabilities discovered by one intelligence agency likely to be discovered by another, or by cybercriminals?

In the past few months, the tech community has acquired some data about this question. In one study, two colleagues from Harvard and I examined over 4,300 disclosed vulnerabilities in common software and concluded that 15 to 20 percent of them are rediscovered within a year. Separately, researchers at the Rand Corporation looked at a different and much smaller data set and concluded that fewer than six percent of vulnerabilities are rediscovered within a year. The questions the two papers ask are slightly different and the results are not directly comparable (we’ll both be discussing these results in more detail at the Black Hat Conference in July), but clearly, more research is needed.

People inside the NSA are quick to discount these studies, saying that the data don’t reflect their reality. They claim that there are entire classes of vulnerabilities the NSA uses that are not known in the research world, making rediscovery less likely. This may be true, but the evidence we have from the Shadow Brokers is that the vulnerabilities that the NSA keeps secret aren’t consistently different from those that researchers discover. And given the alarming ease with which both the NSA and CIA are having their attack tools stolen, rediscovery isn’t limited to independent security research.

But even if it is difficult to make definitive statements about vulnerability rediscovery, it is clear that vulnerabilities are plentiful. Any vulnerabilities that are discovered and used for offense should only remain secret for as short a time as possible. I have proposed six months, with the right to appeal for another six months in exceptional circumstances. The United States should satisfy its offensive requirements through a steady stream of newly discovered vulnerabilities that, when fixed, also improve the country’s defense.

The VEP needs to be reformed and strengthened as well. A report from last year by Ari Schwartz and Rob Knake, who both previously worked on cybersecurity policy at the White House National Security Council, makes some good suggestions on how to further formalize the process, increase its transparency and oversight, and ensure periodic review of the vulnerabilities that are kept secret and used for offense. This is the least we can do. A bill recently introduced in both the Senate and the House calls for this and more.

In the case of EternalBlue, the VEP did have some positive effects. When the NSA realized that the Shadow Brokers had stolen the tool, it alerted Microsoft, which released a patch in March. This prevented a true disaster when the Shadow Brokers exposed the vulnerability on the Internet. It was only unpatched systems that were susceptible to WannaCry a month later, including versions of Windows so old that Microsoft normally didn’t support them. Although the NSA must take its share of the responsibility, no matter how good the VEP is, or how many vulnerabilities the NSA reports and the vendors fix, security won’t improve unless users download and install patches, and organizations take responsibility for keeping their software and systems up to date. That is one of the important lessons to be learned from WannaCry.

This essay originally appeared in Foreign Affairs.

Posted on June 2, 2017 at 6:06 AMView Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.