Entries Tagged "malware"
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Protecting OSs from RootKits
Interesting research: “Countering Kernel Rootkits with Lightweight Hook Protection,” by Zhi Wang, Xuxian Jiang, Weidong Cui, and Peng Ning.
Abstract: Kernel rootkits have posed serious security threats due to their stealthy manner. To hide their presence and activities, many rootkits hijack control flows by modifying control data or hooks in the kernel space. A critical step towards eliminating rootkits is to protect such hooks from being hijacked. However, it remains a challenge because there exist a large number of widely-scattered kernel hooks and many of them could be dynamically allocated from kernel heap and co-located together with other kernel data. In addition, there is a lack of flexible commodity hardware support, leading to the socalled protection granularity gap kernel hook protection requires byte-level granularity but commodity hardware only provides pagelevel protection.
To address the above challenges, in this paper, we present HookSafe, a hypervisor-based lightweight system that can protect thousands of kernel hooks in a guest OS from being hijacked. One key observation behind our approach is that a kernel hook, once initialized, may be frequently “read”-accessed, but rarely “write”-accessed. As such, we can relocate those kernel hooks to a dedicated page-aligned memory space and then regulate accesses to them with hardware-based page-level protection. We have developed a prototype of HookSafe and used it to protect more than 5, 900 kernel hooks in a Linux guest. Our experiments with nine real-world rootkits show that HookSafe can effectively defeat their attempts to hijack kernel hooks. We also show that HookSafe achieves such a large-scale protection with a small overhead (e.g., around 6% slowdown in performance benchmarks).
The research will be presented at the 16th ACM Conference on Computer and Communications Security this week. Here’s an article on the research.
Mossad Hacked Syrian Official's Computer
It was unattended in a hotel room at the time:
Israel’s Mossad espionage agency used Trojan Horse programs to gather intelligence about a nuclear facility in Syria the Israel Defense Forces destroyed in 2007, the German magazine Der Spiegel reported Monday.
According to the magazine, Mossad agents in London planted the malware on the computer of a Syrian official who was staying in the British capital; he was at a hotel in the upscale neighborhood of Kensington at the time.
The program copied the details of Syria’s illicit nuclear program and sent them directly to the Mossad agents’ computers, the report said.
Remember the evil maid attack: if an attacker gets hold of your computer temporarily, he can bypass your encryption software.
"Evil Maid" Attacks on Encrypted Hard Drives
Earlier this month, Joanna Rutkowska implemented the “evil maid” attack against TrueCrypt. The same kind of attack should work against any whole-disk encryption, including PGP Disk and BitLocker. Basically, the attack works like this:
Step 1: Attacker gains access to your shut-down computer and boots it from a separate volume. The attacker writes a hacked bootloader onto your system, then shuts it down.
Step 2: You boot your computer using the attacker’s hacked bootloader, entering your encryption key. Once the disk is unlocked, the hacked bootloader does its mischief. It might install malware to capture the key and send it over the Internet somewhere, or store it in some location on the disk to be retrieved later, or whatever.
You can see why it’s called the “evil maid” attack; a likely scenario is that you leave your encrypted computer in your hotel room when you go out to dinner, and the maid sneaks in and installs the hacked bootloader. The same maid could even sneak back the next night and erase any traces of her actions.
This attack exploits the same basic vulnerability as the “Cold Boot” attack from last year, and the “Stoned Boot” attack from earlier this year, and there’s no real defense to this sort of thing. As soon as you give up physical control of your computer, all bets are off.
Similar hardware-based attacks were among the main reasons why Symantec’s CTO Mark Bregman was recently advised by “three-letter agencies in the US Government” to use separate laptop and mobile device when traveling to China, citing potential hardware-based compromise.
PGP sums it up in their blog.
No security product on the market today can protect you if the underlying computer has been compromised by malware with root level administrative privileges. That said, there exists well-understood common sense defenses against “Cold Boot,” “Stoned Boot” “Evil Maid,” and many other attacks yet to be named and publicized.
The defenses are basically two-factor authentication: a token you don’t leave in your hotel room for the maid to find and use. The maid could still corrupt the machine, but it’s more work than just storing the password for later use. Putting your data on a thumb drive and taking it with you doesn’t work; when you return you’re plugging your thumb into a corrupted machine.
The real defense here is trusted boot, something Trusted Computing is supposed to enable. But Trusted Computing has its own problems, which is why we haven’t seen anything out of Microsoft in the seven-plus years they have been working on it (I wrote this in 2002 about what they then called Palladium).
In the meantime, people who encrypt their hard drives, or partitions on their hard drives, have to realize that the encryption gives them less protection than they probably believe. It protects against someone confiscating or stealing their computer and then trying to get at the data. It does not protect against an attacker who has access to your computer over a period of time during which you use it, too.
EDITED TO ADD (10/23): A few readers have pointed out that BitLocker, the one thing that has come out of Microsoft’s Trusted Computing initiative in the seven-plus years they’ve been working on it, can prevent these sorts of attacks if the computer has a TPM module, version 1.2 or later, on the motherboard. (Note: Not all computers do.) I actually knew that; I just didn’t remember it.
EDITED TO ADD (11/12): Peter Kleissner’s Stoned Boot attacks on TrueCrypt.
EDITED TO ADD (12/9): A similar attack is possible against BitLocker with a TPM.
David Dittrich on Criminal Malware
Good essay: “Malware to crimeware: How far have they gone, and how do we catch up?” ;login:, August 2009:
I have surveyed over a decade of advances in delivery of malware. Over this period, attackers have shifted to using complex, multi-phase attacks based on
subtle social engineering tactics, advanced cyptographic techniques to defeat takeover and analysis, and highly targeted attacks that are intended to fly below the radar of
current technical defenses. I will show how malicious technology combined with social manipulation is used against us and conclude that this understanding might even help us design our own combination of technical and social mechanisms to better protect us.
Malware that Forges Bank Statements
This is brilliant:
The sophisticated hack uses a Trojan horse program installed on the victim’s machine that alters html coding before it’s displayed in the user’s browser, to either erase evidence of a money transfer transaction entirely from a bank statement, or alter the amount of money transfers and balances.
Another article.
If there’s a moral here, it’s that banks can’t rely on the customer to detect fraud. But we already knew that.
Hacking Two-Factor Authentication
Back in 2005, I wrote about the failure of two-factor authentication to mitigate banking fraud:
Here are two new active attacks we’re starting to see:
- Man-in-the-Middle attack. An attacker puts up a fake bank website and entices user to that website. User types in his password, and the attacker in turn uses it to access the bank’s real website. Done right, the user will never realize that he isn’t at the bank’s website. Then the attacker either disconnects the user and makes any fraudulent transactions he wants, or passes along the user’s banking transactions while making his own transactions at the same time.
- Trojan attack. Attacker gets Trojan installed on user’s computer. When user logs into his bank’s website, the attacker piggybacks on that session via the Trojan to make any fraudulent transaction he wants.
See how two-factor authentication doesn’t solve anything? In the first case, the attacker can pass the ever-changing part of the password to the bank along with the never-changing part. And in the second case, the attacker is relying on the user to log in.
Here’s an example:
The theft happened despite Ferma’s use of a one-time password, a six-digit code issued by a small electronic device every 30 or 60 seconds. Online thieves have adapted to this additional security by creating special programs—real-time Trojan horses—that can issue transactions to a bank while the account holder is online, turning the one-time password into a weak link in the financial security chain. “I think it’s a broken model,” Ferrari says.
Of course it’s a broken model. We have to stop trying to authenticate the person; instead, we need to authenticate the transaction:
One way to think about this is that two-factor authentication solves security problems involving authentication. The current wave of attacks against financial systems are not exploiting vulnerabilities in the authentication system, so two-factor authentication doesn’t help.
Security is always an arms race, and you could argue that this situation is simply the cost of treading water. The problem with this reasoning is it ignores countermeasures that permanently reduce fraud. By concentrating on authenticating the individual rather than authenticating the transaction, banks are forced to defend against criminal tactics rather than the crime itself.
Credit cards are a perfect example. Notice how little attention is paid to cardholder authentication. Clerks barely check signatures. People use their cards over the phone and on the Internet, where the card’s existence isn’t even verified. The credit card companies spend their security dollar authenticating the transaction, not the cardholder.
More on mitigating identity theft.
The Global Illicit Economy
A new class of global actors is playing an increasingly important role in globalization: smugglers, warlords, guerrillas, terrorists, gangs, and bandits of all stripes. Since the end of the Cold War, the global illicit economy has consistently grown at twice the rate of the licit global economy. Increasingly, illicit actors will represent not just an economic but a political force. As globalization hollows out traditional nation-states, what will fill the power vacuum in slums and hinterlands will be informal non-state governance structures. These zones will be globally connected, effectively run by local gangs, religious leaders, or quasi-tribal organizations—organizations that will govern without aspiring to statehood.
Malware is one of Nils Gilman’s examples, at about the nine-minute mark.
The seven rules of the illicit global economy (he seems to use “illicit” and “deviant” interchangeably in the talk):
- Perfectly legitimate forms of demand can produce perfectly deviant forms of supply.
- Uneven global regulatory structures create arbitrage opportunities for deviant entrepreneurs.
- Pathways for legitimate globalization are always also pathways for deviant globalization.
- Once a deviant industry professionalizes, crackdowns merely promote innovation.
- States themselves undermine the distinction between legitimate and deviant economics.
- Unchecked, deviant entrepreneurs will overtake the legitimate economy.
- Deviant globalization presents an existential challenge to state legitimacy.
The Security Risks of Accepting Free Laptops
The U.S. Federal Bureau of Investigation is trying to figure out who is sending laptop computers to state governors across the U.S., including West Virginia Governor Joe Mahchin and Wyoming Governor Dave Freudenthal. Some state officials are worried that they may contain malicious software.
Small Business Identity Theft and Fraud
The sorts of crimes we’ve been seeing perpetrated against individuals are starting to be perpetrated against small businesses:
In July, a school district near Pittsburgh sued to recover $700,000 taken from it. In May, a Texas company was robbed of $1.2 million. An electronics testing firm in Baton Rouge, La., said it was bilked of nearly $100,000.
In many cases, the advisory warned, the scammers infiltrate companies in a similar fashion: They send a targeted e-mail to the company’s controller or treasurer, a message that contains either a virus-laden attachment or a link that—when opened—surreptitiously installs malicious software designed to steal passwords. Armed with those credentials, the crooks then initiate a series of wire transfers, usually in increments of less than $10,000 to avoid banks’ anti-money-laundering reporting requirements.
The alert states that these scams typically rely on help from “money mules”—willing or unwitting individuals in the United States—often hired by the criminals via popular Internet job boards. Once enlisted, the mules are instructed to set up bank accounts, withdraw the fraudulent deposits and then wire the money to fraudsters, the majority of which are in Eastern Europe, according to the advisory.
This has the potential to grow into a very big problem. Even worse:
Businesses do not enjoy the same legal protections as consumers when banking online. Consumers typically have up to 60 days from the receipt of a monthly statement to dispute any unauthorized charges.
In contrast, companies that bank online are regulated under the Uniform Commercial Code, which holds that commercial banking customers have roughly two business days to spot and dispute unauthorized activity if they want to hold out any hope of recovering unauthorized transfers from their accounts.
And, of course, the security externality means that the banks care much less:
“The banks spend a lot of money on protecting consumer customers because they owe money if the consumer loses money,” Litan said. “But the banks don’t spend the same resources on the corporate accounts because they don’t have to refund the corporate losses.”
Sidebar photo of Bruce Schneier by Joe MacInnis.