Entries Tagged "side-channel attacks"

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Can the NSA Break AES?

In an excellent article in Wired, James Bamford talks about the NSA’s codebreaking capability.

According to another top official also involved with the program, the NSA made an enormous breakthrough several years ago in its ability to cryptanalyze, or break, unfathomably complex encryption systems employed by not only governments around the world but also many average computer users in the US. The upshot, according to this official: “Everybody’s a target; everybody with communication is a target.”

Bamford has been writing about the NSA for decades, and people tell him all sorts of confidential things. Reading the above, the obvious question to ask is: can the NSA break AES?

My guess is that they can’t. That is, they don’t have a cryptanalytic attack against the AES algorithm that allows them to recover a key from known or chosen ciphertext with a reasonable time and memory complexity. I believe that what the “top official” was referring to is attacks that focus on the implementation and bypass the encryption algorithm: side-channel attacks, attacks against the key generation systems (either exploiting bad random number generators or sloppy password creation habits), attacks that target the endpoints of the communication system and not the wire, attacks that exploit key leakage, attacks against buggy implementations of the algorithm, and so on. These attacks are likely to be much more effective against computer encryption.

EDITED TO ADD (3/22): Another option is that the NSA has built dedicated hardware capable of factoring 1024-bit numbers. There’s quite a lot of RSA-1024 out there, so that would be a fruitful project. So, maybe.

EDITED TO ADD (4/13): The NSA denies everything.

Posted on March 22, 2012 at 7:17 AM • View Comments

Improving the Security of Four-Digit PINs on Cell Phones

The author of this article notices that it’s often easy to guess a cell phone PIN because of smudge marks on the screen. Those smudge marks indicate the four PIN digits, so an attacker knows that the PIN is one of 24 possible permutations of those digits.

Then he points out that if your PIN has only three different digits—1231, for example—the PIN can be one of 36 different possibilities.

So it’s more security, although not much more secure.

Posted on January 6, 2012 at 6:30 AM • View Comments

Smartphone Keystroke Logging Using the Motion Sensor

Clever:

“When the user types on the soft keyboard on her smartphone (especially when she holds her phone by hand rather than placing it on a fixed surface), the phone vibrates. We discover that keystroke vibration on touch screens are highly correlated to the keys being typed.”

Applications like TouchLogger could be significant because they bypass protections built into both Android and Apple’s competing iOS that prevent a program from reading keystrokes unless it’s active and receives focus from the screen. It was designed to work on an HTC Evo 4G smartphone. It had an accuracy rate of more than 70 percent of the input typed into the number-only soft keyboard of the device. The app worked by using the phone’s accelerometer to gauge the motion of the device each time a soft key was pressed.

Paper here. More articles.

Posted on August 23, 2011 at 2:09 PM • View Comments

Breaking the Xilinx Virtex-II FPGA Bitstream Encryption

It’s a power-analysis attack, which makes it much harder to defend against. And since the attack model is an engineer trying to reverse-engineer the chip, it’s a valid attack.

Abstract: Over the last two decades FPGAs have become central components for many advanced digital systems, e.g., video signal processing, network routers, data acquisition and military systems. In order to protect the intellectual property and to prevent fraud, e.g., by cloning an FPGA or manipulating its content, many current FPGAs employ a bitstream encryption feature. We develop a successful attack on the bitstream encryption engine integrated in the widespread Virtex-II Pro FPGAs from Xilinx, using side-channel analysis. After measuring the power consumption of a single power-up of the device and a modest amount of o-line computation, we are able to recover all three different keys used by its triple DES module. Our method allows extracting secret keys from any real-world device where the bitstream encryption feature of Virtex-II Pro is enabled. As a consequence, the target product can be cloned and manipulated at will of the attacker. Also, more advanced attacks such as reverse engineering or the introduction of hardware Trojans become potential threats. As part of the side-channel attack, we were able to deduce certain internals of the hardware encryption engine. To our knowledge, this is the first attack against the bitstream encryption of a commercial FPGA reported in the open literature.

Posted on August 1, 2011 at 12:29 PM • View Comments

Insider Attack Against M&A Information in Document Titles

Protecting against insiders is hard.

Kluger and two accomplices—a Wall Street trader and a mortgage broker—allegedly stole and traded on material nonpublic information about M&A deals over a period of 17 years, according to federal authorities. The trio, facing charges from the U.S. Securities and Exchange Commission and the Department of Justice, allegedly made at least $32 million from the trades….

Kluger had access to information on M&A deals in Wilson Sonsini’s DMS, but he did not open the documents ­ to avoid leaving an audit trail that could possibly expose the scheme, prosecutors assert. Instead, he conducted searches and perused titles. “Kluger looked for board resolutions, press releases, and merger agreements because the titles of these documents revealed that specific companies were involved in pending mergers and acquisitions,” the charges state….

Remember, when people fill out the titles of documents, they are thinking about how to make the document easier to find, not about how to conceal information. Even if the firm uses code names, as was the case in the Wilson Sonsini files, it’s often easy to figure out the codes.

Posted on June 23, 2011 at 6:29 AM • View Comments

Identifying Tor Users Through Insecure Applications

Interesting research: “One Bad Apple Spoils the Bunch: Exploiting P2P Applications to Trace and Profile Tor Users“:

Abstract: Tor is a popular low-latency anonymity network. However, Tor does not protect against the exploitation of an insecure application to reveal the IP address of, or trace, a TCP stream. In addition, because of the linkability of Tor streams sent together over a single circuit, tracing one stream sent over a circuit traces them all. Surprisingly, it is unknown whether this linkability allows in practice to trace a significant number of streams originating from secure (i.e., proxied) applications. In this paper, we show that linkability allows us to trace 193% of additional streams, including 27% of HTTP streams possibly originating from “secure” browsers. In particular, we traced 9% of Tor streams carried by our instrumented exit nodes. Using BitTorrent as the insecure application, we design two attacks tracing BitTorrent users on Tor. We run these attacks in the wild for 23 days and reveal 10,000 IP addresses of Tor users. Using these IP addresses, we then profile not only the BitTorrent downloads but also the websites visited per country of origin of Tor users. We show that BitTorrent users on Tor are over-represented in some countries as compared to BitTorrent users outside of Tor. By analyzing the type of content downloaded, we then explain the observed behaviors by the higher concentration of pornographic content downloaded at the scale of a country. Finally, we present results suggesting the existence of an underground BitTorrent ecosystem on Tor.

Posted on March 25, 2011 at 6:38 AM • View Comments

Attacking High-Frequency Trading Networks

Turns out you can make money by manipulating the network latency.

cPacket has developed a proof of concept showing that these side-channel attacks can be used to create tiny delays in the transmission of market data and trades. By manipulating specific trading activities by several microseconds, an attacker could gain unfair trading advantage. And because the operation occurs outside the range of monitoring technology, it would remain invisible. “We believe that such techniques pose a substantial risk of creating unfair trading, if used by the wrong people,” Kay says.

It’s hard to know how real this threat is. Certainly micro-traders pay attention to latency, and sometimes even place their computers physically close to exchanges so they can reduce latency. And while it would be illegal to deliberately manipulate someone else’s trades, it is probably okay to place a gazillion trades at the same time which—as a side effect—increases latency for everyone else. My guess is that this isn’t a movie-plot threat, and that traders are trying lots of things along this line to give them a small advantage over everyone else.

On the same subject, can anyone explain this?

Posted on January 12, 2011 at 6:59 AM • View Comments

Eavesdropping on Smart Homes with Distributed Wireless Sensors

“Protecting your daily in-home activity information from a wireless snooping attack,” by Vijay Srinivasan, John Stankovic, and Kamin Whitehouse:

Abstract: In this paper, we first present a new privacy leak in residential wireless ubiquitous computing systems, and then we propose guidelines for designing future systems to prevent this problem. We show that we can observe private activities in the home such as cooking, showering, toileting, and sleeping by eavesdropping on the wireless transmissions of sensors in a home, even when all of the transmissions are encrypted. We call this the Fingerprint and Timing-based Snooping (FATS) attack. This attack can already be carried out on millions of homes today, and may become more important as ubiquitous computing environments such as smart homes and assisted living facilities become more prevalent. In this paper, we demonstrate and evaluate the FATS attack on eight different homes containing wireless sensors. We also propose and evaluate a set of privacy preserving design guidelines for future wireless ubiquitous systems and show how these guidelines can be used in a hybrid fashion to prevent against the FATS attack with low implementation costs.

The group was able to infer surprisingly detailed activity information about the residents, including when they were home or away, when they were awake or sleeping, and when they were performing activities such as showering or cooking. They were able to infer all this without any knowledge of the location, semantics, or source identifier of the wireless sensors, while assuming perfect encryption of the data and source identifiers.

Posted on August 31, 2010 at 12:39 PM • View Comments

Security Analysis of Smudges on Smart Phone Touch Screens

“Smudge Attacks on Smartphone Touch Screens“:

Abstract: Touch screens are an increasingly common feature on personal computing devices, especially smartphones, where size and user interface advantages accrue from consolidating multiple hardware components (keyboard, number pad, etc.) into a single software definable user interface. Oily residues, or smudges, on the touch screen surface, are one side effect of touches from which frequently used patterns such as a graphical password might be inferred.

In this paper we examine the feasibility of such smudge attacks on touch screens for smartphones, and focus our analysis on the Android password pattern. We first investigate the conditions (e.g., lighting and camera orientation) under which smudges are easily extracted. In the vast majority of settings, partial or complete patterns are easily retrieved. We also emulate usage situations that interfere with pattern identification, and show that pattern smudges continue to be recognizable. Finally, we provide a preliminary analysis of applying the information learned in a smudge attack to guessing an Android password pattern.

Reminds me of similar attacks on alarm and lock keypads.

Posted on August 12, 2010 at 6:48 AM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.