Entries Tagged "exploits"

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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.

Posted on May 25, 2011 at 11:55 AM • View Comments

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.

Posted on December 1, 2010 at 5:55 AM • View Comments

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.

Posted on August 10, 2010 at 12:12 PM • View Comments

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.”

Posted on June 10, 2009 at 1:51 PM • View Comments

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.

Posted on April 23, 2008 at 1:35 PM • View Comments

SANS Top 20

Every year SANS publishes a list of the 20 most important vulnerabilities. It’s always a great list, and this year is no different:

The threat landscape is very dynamic, which in turn makes it necessary to adopt newer security measures. Just over the last year, the kinds of vulnerabilities that are being exploited are very different from the ones being exploited in the past. Here are some observations:

  • Operating systems have fewer vulnerabilities that can lead to massive Internet worms. For instance, during 2002-2005, Microsoft Windows worms like Blaster, Nachi, Sasser and Zotob infected a large number of systems on the Internet. There have not been any new large-scale worms targeting Windows services since 2005. On the other hand, vulnerabilities found anti-virus, backup or other application software, can result in worms. Most notable was the worm exploiting the Symantec anti-virus buffer overflow flaw last year.
  • We have seen significant growth in the number of client-side vulnerabilities, including vulnerabilities in browsers, in office software, in media players and in other desktop applications. These vulnerabilities are being discovered on multiple operating systems and are being massively exploited in the wild, often to drive recruitment for botnets.
  • Users who are allowed by their employers to browse the Internet have become a source of major security risk for their organizations. A few years back securing servers and services was seen as the primary task for securing an organization. Today it is equally important, perhaps even more important, to prevent users having their computers compromised via malicious web pages or other client-targeting attacks.
  • Web application vulnerabilities in open-source as well as custom-built applications account for almost half the total number of vulnerabilities being discovered in the past year. These vulnerabilities are being exploited widely to convert trusted web sites into malicious servers serving client-side exploits and phishing scams.
  • The default configurations for many operating systems and services continue to be weak and continue to include default passwords. As a result, many systems have been compromised via dictionary and brute-force password guessing attacks in 2007!
  • Attackers are finding more creative ways to obtain sensitive data from organizations. Therefore, it is now critical to check the nature of any data leaving an organization’s boundary.

Much, much more information at the link.

Posted on December 3, 2007 at 3:12 PM • View Comments

New German Hacking Law

There has been much written about the new German hacker-tool law, which went into effect earlier this month.

Dark Reading has the most interesting speculation:

Many security people say the law is so flawed and so broad and that no one can really comply with it. “In essence, the way the laws are phrased now, there is no way to ever comply… even as a non-security company,” says researcher Halvar Flake, a.k.a. Thomas Dullien, CEO and head of research at Sabre Security.

“If I walked into a store now and told the clerk that I wish to buy Windows XP and I will use it to hack, then the clerk is aiding me in committing a crime by [selling me] Windows XP,” Dullien says. “The law doesn’t actually distinguish between what the intended purpose of a program is. It just says if you put a piece of code in a disposition that is used to commit a crime, you’re complicit in that crime.”

Dullien says his company’s BinNavi tool for debugging and analyzing code or malware is fairly insulated from the law because it doesn’t include exploits. But his company still must ensure it doesn’t sell to “dodgy” customers.

Many other German security researchers, meanwhile, have pulled their proof-of-concept exploit code and hacking tools offline for fear of prosecution.

[…]

The German law has even given some U.S. researchers pause as well. It’s unclear whether the long arm of the German law could reach them, so some aren’t taking any chances: The exploit-laden Metasploit hacking tool could fall under German law if someone possesses it, distributes it, or uses it, for instance. “I’m staying out of Germany,” says HD Moore, Metasploit’s creator and director of security research for BreakingPoint Systems.

“Just about everything the Metasploit project provides [could] fall under that law,” Moore says. “Every exploit, most of the tools, and even the documentation in some cases.”

Moore notes that most Linux distros are now illegal in Germany as well, because they include the open-source nmap security scanner tool—and some include Metasploit as well.

The law basically leaves the door open to outlaw any software used in a crime, notes Sabre Security’s Dullien.

Zoller says the biggest problem with the new law is that it’s so vague that no one really knows what it means yet. “We have to wait for something to happen to know the limits.”

Posted on August 28, 2007 at 1:32 PM • View Comments

Are Port Scans Precursors to Attack?

Interesting research:

Port scans may not be a precursor to hacking efforts, according to conventional wisdom, reports the University of Maryland’s engineering school.

An analysis of quantitative attack data gathered by the university over a two-month period showed that port scans precede attacks only about five percent of the time, said Michel Cukier, a professor in the Centre for Risk and Reliability. In fact, more than half of all attacks aren’t preceded by a scan of any kind, Cukier said.

I agree with Ullrich, who said that the analysis seems too simplistic:

Johannes Ullrich, chief technology officer at the SANS Institute ‘s Internet Storm Center, said that while the design and development of the testbed used for the research appears to be valid, the analysis is too simplistic.

Rather than counting the number of packets in a connection, it’s far more important to look at the content when classifying a connection as a port scan or an attack, Ullrich said.

Often, attacks such as the SQL Slammer worm, which hit in 2003, can be as small as one data packet, he said. A lot of the automated attacks that take place combine port and vulnerability scans and exploit code, according to Ullrich.

As a result, much of what researchers counted as port scans may have actually been attacks, said Ullrich, whose Bethesda, Md.-based organization provides Internet threat-monitoring services.

Posted on December 15, 2005 at 6:38 AM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.