Has Tor Been Compromised?
There’s speculation that the FBI is responsible for an exploit that compromised the Tor anonymity service. Note that Tor nodes Browser Bundles installed or updated after June 26 are secure.
Entries Tagged "exploits"
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The US Uses Vulnerability Data for Offensive Purposes
Companies allow US intelligence to exploit vulnerabilities before it patches them:
Microsoft Corp. (MSFT), the world’s largest software company, provides intelligence agencies with information about bugs in its popular software before it publicly releases a fix, according to two people familiar with the process. That information can be used to protect government computers and to access the computers of terrorists or military foes.
Redmond, Washington-based Microsoft (MSFT) and other software or Internet security companies have been aware that this type of early alert allowed the U.S. to exploit vulnerabilities in software sold to foreign governments, according to two U.S. officials. Microsoft doesn’t ask and can’t be told how the government uses such tip-offs, said the officials, who asked not to be identified because the matter is confidential.
No word on whether these companies would delay a patch if asked nicely—or if there’s any way the government can require them to. Anyone feel safer because of this?
Remotely Hijacking an Aircraft
There is a lot of buzz on the Internet about a talk at the Hack-in-the Box conference by Hugo Teso, who claims he can hack in to remotely control an airplane’s avionics. He even wrote an Android app to do it.
I honestly can’t tell how real this is, and how much of it is the unique configuration of simulators he tested this on. On the one hand, it can’t possibly be true that an aircraft avionics computer accepts outside commands. On the other hand, we’ve seen lots of security vulnerabilities that seem impossible to be true. Right now, I’m skeptical.
EDITED TO ADD (4/12): Three good refutations.
Studying Zero-Day Attacks
Interesting paper: “Before We Knew It: An Empirical Study of Zero-Day Attacks In The Real World,” by Leyla Bilge and Tudor Dumitras:
Abstract: Little is known about the duration and prevalence of zeroday attacks, which exploit vulnerabilities that have not been disclosed publicly. Knowledge of new vulnerabilities gives cyber criminals a free pass to attack any target of their choosing, while remaining undetected. Unfortunately, these serious threats are difficult to analyze, because, in general, data is not available until after an attack is discovered. Moreover, zero-day attacks are rare events that are unlikely to be observed in honeypots or in lab experiments.
In this paper, we describe a method for automatically identifying zero-day attacks from field-gathered data that records when benign and malicious binaries are downloaded on 11 million real hosts around the world. Searching this data set for malicious files that exploit known vulnerabilities indicates which files appeared on the Internet before the corresponding vulnerabilities were disclosed. We identify 18 vulnerabilities exploited before disclosure, of which 11 were not previously known to have been employed in zero-day attacks. We also find that a typical zero-day attack lasts 312 days on average and that, after vulnerabilities are disclosed publicly, the volume of attacks exploiting them increases by up to 5 orders of magnitude.
Blackhole Exploit Kit
It’s now available as a free download:
A free version of the Blackhole exploit kit has appeared online in a development that radically reduces the entry-level costs of getting into cybercrime.
The Blackhole exploit kit, which up until now would cost around $1,500 for an annual licence, creates a handy way to plant malicious scripts on compromised websites. Surfers visiting legitimate sites can be redirected using these scripts to scareware portals on sites designed to exploit browser vulnerabilities in order to distribute banking Trojans, such as those created from the ZeuS toolkit.
Software Monoculture
In 2003, a group of security experts—myself included—published a paper saying that 1) software monocultures are dangerous and 2) Microsoft, being the largest creator of monocultures out there, is the most dangerous. Marcus Ranum responded with an essay that basically said we were full of it. Now, eight years later, Marcus and I thought it would be interesting to revisit the debate.
The basic problem with a monoculture is that it’s all vulnerable to the same attack. The Irish Potato Famine of 1845–9 is perhaps the most famous monoculture-related disaster. The Irish planted only one variety of potato, and the genetically identical potatoes succumbed to a rot caused by Phytophthora infestans. Compare that with the diversity of potatoes traditionally grown in South America, each one adapted to the particular soil and climate of its home, and you can see the security value in heterogeneity.
Similar risks exist in networked computer systems. If everyone is using the same operating system or the same applications software or the same networking protocol, and a security vulnerability is discovered in that OS or software or protocol, a single exploit can affect everyone. This is the problem of large-scale Internet worms: many have affected millions of computers on the Internet.
If our networking environment weren’t homogeneous, a single worm couldn’t do so much damage. We’d be more like South America’s potato crop than Ireland’s. Conclusion: monoculture is bad; embrace diversity or die along with everyone else.
This analysis makes sense as far as it goes, but suffers from three basic flaws. The first is the assumption that our IT monoculture is as simple as the potato’s. When the particularly virulent Storm worm hit, it only affected from 1–10 million of its billion-plus possible victims. Why? Because some computers were running updated antivirus software, or were within locked-down networks, or whatever. Two computers might be running the same OS or applications software, but they’ll be inside different networks with different firewalls and IDSs and router policies, they’ll have different antivirus programs and different patch levels and different configurations, and they’ll be in different parts of the Internet connected to different servers running different services. As Marcus pointed out back in 2003, they’ll be a little bit different themselves. That’s one of the reasons large-scale Internet worms don’t infect everyone—as well as the network’s ability to quickly develop and deploy patches, new antivirus signatures, new IPS signatures, and so on.
The second flaw in the monoculture analysis is that it downplays the cost of diversity. Sure, it would be great if a corporate IT department ran half Windows and half Linux, or half Apache and half Microsoft IIS, but doing so would require more expertise and cost more money. It wouldn’t cost twice the expertise and money—there is some overlap—but there are significant economies of scale that result from everyone using the same software and configuration. A single operating system locked down by experts is far more secure than two operating systems configured by sysadmins who aren’t so expert. Sometimes, as Mark Twain said: “Put all your eggs in one basket, and then guard that basket!”
The third flaw is that you can only get a limited amount of diversity by using two operating systems, or routers from three vendors. South American potato diversity comes from hundreds of different varieties. Genetic diversity comes from millions of different genomes. In monoculture terms, two is little better than one. Even worse, since a network’s security is primarily the minimum of the security of its components, a diverse network is less secure because it is vulnerable to attacks against any of its heterogeneous components.
Some monoculture is necessary in computer networks. As long as we have to talk to each other, we’re all going to have to use TCP/IP, HTML, PDF, and all sorts of other standards and protocols that guarantee interoperability. Yes, there will be different implementations of the same protocol—and this is a good thing—but that won’t protect you completely. You can’t be too different from everyone else on the Internet, because if you were, you couldn’t be on the Internet.
Species basically have two options for propagating their genes: the lobster strategy and the avian strategy. Lobsters lay 5,000 to 40,000 eggs at a time, and essentially ignore them. Only a minuscule percentage of the hatchlings live to be four weeks old, but that’s sufficient to ensure gene propagation; from every 50,000 eggs, an average of two lobsters is expected to survive to legal size. Conversely, birds produce only a few eggs at a time, then spend a lot of effort ensuring that most of the hatchlings survive. In ecology, this is known as r/K selection theory. In either case, each of those offspring varies slightly genetically, so if a new threat arises, some of them will be more likely to survive. But even so, extinctions happen regularly on our planet; neither strategy is foolproof.
Our IT infrastructure is a lot more like a bird than a lobster. Yes, monoculture is dangerous and diversity is important. But investing time and effort in ensuring our current infrastructure’s survival is even more important.
This essay was originally published in Information Security, and is the first half of a point/counterpoint with Marcus Ranum. You can read his response there as well.
EDITED TO ADD (12/13): Commentary.
Apple JailBreakMe Vulnerability
Good information from Mikko Hyppönen.
Q: What is this all about?
A: It’s about a site called jailbreakme.com that enables you to Jailbreak your iPhones and iPads just by visiting the site.Q: So what’s the problem?
A: The problem is that the site uses a zero-day vulnerability to execute code on the device.Q: How does the vulnerability work?
A: Actually, it’s two vulnerabilities. First one uses a corrupted font embedded in a PDF file to execute code and the second one uses a vulnerability in the kernel to escalate the code execution to unsandboxed root.Q: How difficult was it to create this exploit?
A: Very difficult.Q: How difficult would it be for someone else to modify the exploit now that it’s out?
A: Quite easy.
Here’s the JailBreakMe blog.
EDITED TO ADD (8/14): Apple has released a patch. It doesn’t help people with old model iPhones and iPod Touches, or work for people who’ve jailbroken their phones.
EDITED TO ADD (8/15): More info.
Malware Steals ATM Data
One of the risks of using a commercial OS for embedded systems like ATMs: it’s easier to write malware against it:
The report does not detail how the ATMs are infected, but it seems likely that the malware is encoded on a card that can be inserted in an ATM card reader to mount a buffer overflow attack. The machine is compromised by replacing the isadmin.exe file to infect the system.
The malicious isadmin.exe program then uses the Windows API to install the functional attack code by replacing a system file called lsass.exe in the C:WINDOWS directory.
Once the malicious lsass.exe program is installed, it collects users account numbers and PIN codes and waits for a human controller to insert a specially crafted control card to take over the ATM.
After the ATM is put under control of a human attacker, they can perform various functions, including harvesting the purloined data or even ejecting the cash box.
EDITED TO ADD (6/14): Seems like the story I quoted was jumping to conclusions. The actual report says “the malware is installed and activated through a dropper file (a file that an attacker can use to deploy tools onto a compromised system) by the name of isadmin.exe,” which doesn’t really sound like it’s referring to a buffer overflow attack carried out through a card emulator. Also, The Register says “[the] malicious programs can be installed only by people with physical access to the machines, making some level of insider cooperation necessary.”
Watching a Malware Author Work
Using the incremental update feature of pdf files to watch a malware author create his exploit.
Reverse-Engineering Exploits from Patches
This is interesting research: given a security patch, can you automatically reverse-engineer the security vulnerability that is being patched and create exploit code to exploit it?
Turns out you can.
What does this mean?
Attackers can simply wait for a patch to be released, use these techniques, and with reasonable chance, produce a working exploit within seconds. Coupled with a worm, all vulnerable hosts could be compromised before most are even aware a patch is available, let alone download it. Thus, Microsoft should redesign Windows Update. We propose solutions which prevent several possible schemes, some of which could be done with existing technology.
Full paper here.
Sidebar photo of Bruce Schneier by Joe MacInnis.