Corporate custodians of confidential medical data should be closely monitoring events connected to a nightmarish computer security breach in the St. Louis region.

Express Scripts is one of the nation’s largest pharmacy benefits managers. The company, with headquarters in St. Louis County, handles approximately 500 million prescriptions per year for 50 million workers at 1,600 American companies. Early in October, it received an extortion letter, the details of which it released on Nov. 6.

The letter included personal information on about 75 Express Scripts clients — Social Security numbers, dates of birth and, in some cases, information about prescription medications. Whoever sent the letter demanded money from the company — the amount has not been disclosed — and threatened to use the Internet to reveal personal and medical information about millions of people if the demands were not met.

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Beyond the scale of the problem for Express Scripts — and the potential impact on the company is enormous — the issue extends well beyond the mounting concerns about identity theft, a phenomenon with which most people have become at least somewhat familiar.

The greater problem is the unique nature of personal medical records, the importance of moving to computerization of such records to improve health safety and reduce costs and the irreversibility of the damage people can suffer if confidential medical information becomes public. The stakes are so high that a federal law establishes strict standards for maintaining the privacy of medical information and stiff fines for failing to do so.

Medical records of all kinds — paper and, especially, electronic — must be protected with the most sophisticated kinds of security systems available, including backup protections and automatic alerts of security violations. Yet Express Scripts learned of this breach in the “worst way,” as InformationWeek.com security correspondent George Hulme put it in an online report: “via an extortion letter.”

The Express Scripts breach raises many questions for all elements of the health industry: hospitals, clinics and doctors’ practices, benefits management firms, insurance companies, pharmacies, employers and government agencies:
Are they using the most advanced information security technology possible? Do they minimize the amount of data they collect and keep it only as long as necessary? Do they have strict protocols governing access to personal and medical data — and systems to enforce those protocols? If criminals were to hack into their systems, how would the companies know? How soon? And are the systems capable of instantly cutting off illegal access as soon as a breach is discovered?

Confronted with a grave breach of electronic security, Express Scripts has responded by contacting law enforcement, establishing an informational website, offering a substantial reward and hiring a private consulting firm to help clients who have privacy concerns and investigate situations that “appear to be tied to identity theft” and provide “identity restoration services.” There is no question that the company is taking the situation extremely seriously.
Given the ongoing criminal situation, information about how Express Scripts’ data systems were compromised — and whether it could have been avoided — has yet to be disclosed. But the American people have the right to expect that their sensitive personal and medical information is zealously protected and kept secure — not only by Express Scripts but also by every person or company entrusted with it.

"Customers and customer relationships...have tangible measurable value to businesses, and their value is much easier to communicate to those who fund projects. So in an enterprise risk management scenartio, their vlaue informs the risk management process...[For example, consider] a farmer deciding which crop to grow. A farmer interested in short term profits may grow the same high yield crop every year, but over time this would burn the fields out. The long term focused farmer would rotate the crops and invest in things that build the value of the farm and soil over time. Investing in security on behalf of your customers is like this. The investment made in securing your customer's data build current and future value for them. Measuring the value of the customer and relationships helps to target where to allocate security resources."

• The transport – processing Syslog events takes up a heck of a lot less processing power than collecting from a Windows box. Same with collecting data over an ODBC connection.

The exploit involved the very powerful (500KW) Aspidistra transmitter, coupled to a directional antenna farm. With that power, they could make it sound like a local station in the target area.

With a staff of fake announcers, a fake German band, and recordings of recent speeches from high-ranking Nazis, they would smoothly switch from merely relaying the German network to emulating it with their own staff. They could then make modifications to news broadcasts, occasionally creating panic and confusion.

German transmitters were switched off during air raids, to prevent them from being used as navigational aids for bombers. But many were connected into a network and broadcast the same content. When a targeted transmitter switched off, Aspidistra began transmitting on their original frequency, initially retransmitting the German network broadcast as received from a still-active station. As a deception, false content and pro-Allied propaganda would be inserted into the broadcast. The first such "intrusion" was carried out on March 25, 1945, as shown in the operations order at the right.

On March 30, 1945, "Aspidistra" intruded into the Berlin and Hamburg frequencies warning that the Allies were trying to spread confusion by sending false telephone messages from occupied towns to unoccupied towns. On April 8, 1945, "Aspidistra" intruded into the Hamburg and Leipzig channels to warn of forged banknotes in circulation. On April 9, 1945, there were announcements encouraging people to evacuate to seven bomb-free zones in central and southern Germany. All these announcements were false.

The German radio network tried announcing "The enemy is broadcasting counterfeit instructions on our frequencies. Do not be misled by them. Here is an official announcement of the Reich authority." The Aspidistra station made similar announcements, to cause confusion and make the official messages ineffective.

No longer are OS vendors and other large infrastructure technology providers the main source of vulnerabilities. It’s the thousands of applications, produced by thousands of software vendors, that make up this huge 3rd wave. ISS reported that in 2007 that the top five sources of vulnerabilities: Microsoft, Apple, Oracle, IBM, and Cisco, had dropped to supplying us with only 13.6% of our vulnerabilities. 86.4% came from the other thousands of software vendors that supply our computers with a seemingly unending supply of vulnerabilities for attackers to exploit.

In a recent report Microsoft has congratulated itself on doing a good job securing Windows. And by all accounts they have done a good job. But then they state this:

“Unless software development practices change throughout the industry, any improvements in the security of Windows would be meaningless.”

Whoa. Millions of dollars spent on securing the most prevalent piece of software and it could be meaningless? Yes, it’s true. Since attackers typically only need one vulnerability, if it isn’t in the network, and it isn’t in the host configuration, and it isn’t in the OS, they will happily exploit a vulnerability in an application.

At every shift of exploit target the problem has gotten more difficult to solve. Networks had choke points and could be centrally managed. It took a while but eventually host configurations became centrally managed and automated tools could scan configurations. Although OSes were huge and complex beasts with 10’s of millions of lines of code, with enough effort, their vulnerabilities have been largely tamed as Microsoft’s Windows and the Linux kernel track record shows. This was a very substantial, over five year effort, which used some of the most talented security people anywhere.
But now what to do? Instead of a few OSes we now have thousands of applications with vulnerabilities. As Microsoft found out, the attackers don’t go away, they just move on to the next incrementally less juicy vulnerability. In the world of exploits that typically means the vulnerability with the next smallest target population.

Attackers have started with the common client applications that can be found on almost every machine: Acrobat, Flash, RealPlayer, Quicktime, popular antivirus software. And they will continue down the popularity slope until they get to application populations down in the thousands which is getting to fairly small software vendors. Attackers can do this because they can bundle many vulnerabilities together, exploiting the statistical fact that you must have some vulnerable software installed. Compromised web sites have been found attacking visitors with over ten client side exploits preying on multiple versions of vulnerable client software.

The solution to this problem is all software must be written securely, not just the software from the big guys. Small vendors think they aren’t a target just like home users used to think they weren’t a target. People thought, “Why would someone want to attack my home computer?” Then they realized they did home banking, or had a fast internet connection that could be used for DDoS attacks or sending spam. All software vendors need to get the same wakeup call. Attackers don’t want to find a vulnerability in your software to make you look bad. They want any vulnerability. If the population of your software is small they will just bundle your vulnerability together with others in an exploit pack. The days of the average software vendor not having to worry about application security are officially over.

I find that legacy code poses a unique challenge for organizations rolling out a new security process.  Often, the resources dedicated to maintaining older code are a small fraction of those devoted to new features or products.  Furthermore, the original developers for such features have often moved on, leaving no subject matter experts to drive reviews.  The astute reader will ask “How do I apply the principles of the Microsoft SDL to legacy code when I have no development resources and nobody knows how it works?”

The answer is “Start small, and build expertise over time.”

A Rising Tide Lifts All Boats

The best thing a security engineering team can do to improve security in the short term is to drive code quality, and the first step in this process is to define and enforce a secure coding standard.  This helps on two fronts: 

1.       It will improve code quality and reduce implementation flaws across the entire code base.  Unlike other security processes, driving a secure coding standard is relatively easy to accomplish across an entire code base, regardless of the code’s age, by a focused security team.  That is not to say that it is easy without qualification – a large batch of spaghetti code will require a lot of work to untangle!  Such an effort can only be called “easy” when compared to, say, comprehensive identification and remediation of design flaws across legacy features.  Even so, improving code quality through the use of secure coding standards offers a unique combination of high impact, applicability to features, and ability to be carried out by a core team that makes it a sensible first step.

2.       The security team might notice that some sections of code have more standards violations or outright flaws than others.  This is an instance of vulnerability clustering, a concept that has been used to predict vulnerability rates and improve quality in the functional realm.  The evidence is anecdotal, but it stands to reason that portions of code that consistently violate secure coding standards are good places to start looking for other classes of security flaw.  These are security hotspots, and should be high on the prioritized list for further review.

Security testing may also be applied to legacy code, but initial activities should be considered on a case-by-case basis based on the expected return on investment.  Such testing ranges from using inexpensive off-the-shelf tools to exercise common interfaces to rather expensive custom testing and formal analysis.  It is worthwhile to begin with off-the-shelf tools, such as those that target file parsers or web applications, and tools created as part of your greater secure development efforts.  These can help identify easily-found flaws and suggest improvements to the coding standards.  Comprehensive security testing, on the other hand, is best tackled after the Legacy Security Push.

The Legacy Security Push

Coding standards and basic testing provide bang for the buck, but formal security processes seek to provide security assurance.  The challenge for legacy code is that it needs to play catch-up.  Security processes that occur early in the development cycle, such as requirements analysis, design review, and threat modeling, are particularly difficult to achieve years after the fact.  The main goal of the Legacy Security Push is to create the deliverables from these efforts, the most important of which are security requirements and a full risk analysis.

It may sound trivial, but security requirements are essential.  Not only do they define proper operation for the system in question, they also define assumptions that are suitable for relying systems.   It is very common to find security flaws in legacy systems that arise from well-intentioned but incorrect assumptions such as “I assume that the Foo authenticates server Bar when initiating a bank transfer.”  It stands to reason that Foo would do so for such an important activity, but this assumption must be validated.  It is very common for older features to have been deployed in and written for different environments where the security assumptions that are "obvious" today just didn't apply at the time.

When reviewing legacy systems, the first step is to identify such requirements.  If the original architects, developers or managers are available, they can provide valuable insight at this stage.  More often than not this is not the case, and analysis must instead rely on what documentation is present and interaction between the software and its consumers.  The goal is the same as in requirements analysis during project inception, except that in this case one must turn the process on its head and reverse engineer requirements from system behavior.  At the conclusion of this effort, requirements can be theorized – “Foo must authenticate its server Bar before initiating a bank transfer.” 

Risk analysis can be performed once a plausible set of requirements have been identified.  Threat modeling is a more structured means of performing such an analysis, with the eventual goal of identifying means by which requirements can be violated by an attacker. 

As with requirements analysis, original developers would be a valuable resource to consult.  With or without such help, the first step is to identify how the software works.  In many cases, help is not available and performing this task requires a great deal of effort.  For features of moderate size, this author has spent upwards of a month reading code, using process profiling tools, and walking through the software with a debugger to identify program flow and security-sensitive functionality.

Once completed, actual system behavior should be documented and compared against the requirements theorized.   It might be that the requirements should be re-evaluated (New requirement:  Do not assume that Foo requires server authentication) or the system may need to be changed (New bug:   Foo does not verify the CN for Bar).  At the end, this information should be sufficient to support a comprehensive threat modeling exercise where security requirements, risks, and their mitigations can be documented.

Next Steps

Bringing a legacy feature up to par with its newer kin requires a relatively small number of items:  improved code quality, clear security requirements, and a thorough threat model.  As we have seen, performing even these tasks is quite the effort!  I am sure that it is little comfort to be reminded that accomplishing these tasks has simply laid the foundation, and that the true benefit is that the newly-reviewed legacy feature is able to participate fully in the security processes that remain: reviewing cross-component security requirements and assumptions, comprehensive testing, and incident planning, to name a few.

Unfortunately, there is no silver bullet in security assurance.  The soundness of the design and implementation of legacy software is just as important as in newer software, which is why any complete secure software development process will look backwards as well as forwards.  Feature by feature, from higher priority to lower, the overall security of the software improves as legacy code receives the full security treatment it deserves.

The researchers from the Security and Cryptography Laboratory at Ecole Polytechnique Federale de Lausanne are able to capture keystrokes by monitoring the electromagnetic radiation of PS/2, universal serial bus, or laptop keyboards. They've outline four separate attack methods, some that work at a distance of as much as 65 feet from the target.

In one video demonstration, researchers Martin Vuagnoux and Sylvain Pasini sniff out the the keystrokes typed into a standard keyboard using a large antenna that's about 20 to 30 feet away in an adjacent room.

Website here.