Research

*Updated:** 8/25/2010 Storefront-Backtalk magazine had an interesting post on Too Much Encrypt = Cyberthief Gift. And when I say ‘interesting’, I mean the topics are interesting, but the author (Walter Conway) seems to have gotten most of the facts wrong in an attempt to hype the story. The basic scenario the author describes is correct: when you encrypt a very small range of numbers/values, it is possible to pre-compute (encrypt) all of those values, then match them against the encrypted values you see in the wild. The data may be encrypted, but you know the contents because the encrypted values match. The point the author is making is that if you encrypt the expiration date of a credit card, an attacker can easily guess the value. OK, but what’s the problem? The guys over at Voltage hit the basic point on the head: it does not compromise the system. The important point is that you cannot derive the key from this form of attack. Sure, you can you confirm the contents of the enciphered text. This is not really an attack on the encryption algorithm, nor the key, but poorly deployed cryptography. It’s one of the interesting aspects of encryption or hashing functions; if you make the smallest of changes to the input, you get a radically different output. If you add randomness (Updated: per Jay’s comments below, this was not clear; Initialization Vector or feedback modes for encryption) or even somewhat random “salting” (for hashing) we have an effective defense against rainbow tables, dictionary attacks, and pattern matching. In an ideal world we would do this. It’s possible some places don’t … in commodity hardware, for example. It did dawn on me that this sort of weakness lingers on in many Point of Sale terminals that sell on speed and price, not security. These (relatively) cheap appliances don’t usually implement the best security: they use the fastest rather than the strongest cryptography, they keep key lengths short, they don’t do a great job at gathering randomness, and generally skimp on the mechanical aspects of cryptography. They also are designed for speed, low cost, and generic deployments: salting or concatenation of PAN with the expiration date is not always an option, or significant adjustments to the outbound data stream would raise costs. But much of the article talks about data storage, or the back end, and not the POS system. The premise of “Encrypting all your data may actually make you more vulnerable to a data breach” is BS. It’s not an issue of encrypting too much, it’s in those rare cases where you encrypt in very small digestible fields. “Encrypting all cardholder data that not only causes additional work but may actually make you more vulnerable to a data breach” is total nonsense. If you encrypt all of the data, especially if you concatenate the data, the resulting ciphertext does not suffer from the described attack. Further, I don’t believe that “Most retailers and processors encrypt their entire cardholder database”, making them vulnerable. If they encrypt the entire database, they use transparent encryption, so the data blocks are encrypted as whole elements. The block contents are random so each has some degree of natural randomness going on because the database structure and pointers are present. And if they are using application layer or field level encryption, they usually salt alter the initialization vector. Or concatenate the entire record. And that’s not subject to a simple dictionary attack, and in no way produces a “Cyberthief Gift”. Share:

Starting in early September, I’ll be doing a series of webcasts digging into the Endpoint Security Fundamentals paper we published over the summer. Since there is a lot of ground to cover, we’ll be doing three separate webcasts, each focused on a different aspect. The webcasts will be very little talking-head stuff (you can read the paper for that). We’ll spend most of the time doing Q&A. So check out the paper, bring your questions, and have a good time. As with the paper, Lumension Security is sponsoring the webcasts. You can sign up for a specific webcast (or all 3) by clicking here. Here is the description: Endpoint Security Fundamentals In today’s mobile, always on business environment, information is moving further away from the corporate boundaries to the endpoints. Cyber criminals have more opportunities than ever to gain unauthorized access to valuable data. Endpoints now store the crown jewels; including financial records, medical records, trade secrets, customer lists, classified information, etc. Such valuable data fuels the on-demand business environment, but also creates a dilemma for security professionals to determine the best way to protect it. This three part webcast series on Endpoint Security Fundamentals examines how to build a real-world, defense-in-depth security program – one that is sustainable and does not impede business productivity. Experts who will lead the discussion are Mike Rothman, Analyst and President of Securosis, and Jeff Hughes, Director of Solution Marketing with Lumension. Part 1 – Finding and Fixing the Leaky Buckets September 8, 2010 11 AM ET (Register Here) Part 1 of this webcast series will discuss the first steps to understanding your IT risk and creating the necessary visibility to set up a healthy endpoint security program. We will examine: The fundamental steps you should take before implementing security enforcement solutions How to effectively prioritize your IT risks so that you are focusing on what matters most How to act on the information that you gather through your assessment and prioritization efforts How to get some “quick wins” and effectively communicate security challenges with your senior management Part 2 – Leveraging the Right Enforcement Controls September 22, 2010 11 AM ET (Register Here) Part 2 of this webcast series examines key enforcement controls including: How to automate the update and patch management process across applications and operating systems to ensure all software is current How to define and enforce standardized and secure endpoint configurations How to effectively layer your defense and the evolving role that application whitelisting plays How to implement USB device control and encryption technologies to protect data Part 3 – Building the Endpoint Security Program October 6, 2010 11 AM ET (Register Here) In this final webcast of our series, we take the steps and enforcement controls discussed from webcasts 1 and 2 and discuss how to meld them into a true program, including: How to manage expectations and define success How to effectively train your users about policies and how to ensure two-way communication to evolve policies as needed How to effectively respond to incidents when they occur to minimize potential damage How to document and report on your overall security and IT risk posture Hope to see you for all three events. Share: