Monday, June 22, 2020

On "Ransomware"

Forty years ago, my friend and colleague, Donn Parker, suggested that "employees" would use cryptography to hide enterprise data from management.  Employees because forty years ago only one's employees could send a message to one's systems.  I laughed.  It was obvious to me that such an activity would require both "read" and "write" access to the data.  I was so young and naive that I could not foresee a world in which most of those connected to enterprise systems would be outsiders, including sophisticated criminal enterprises.  Mostly, I could not anticipate a world in which "read/write" would be the default access control rule, not only for data, but also for programs.  

We are now three years since the first "ransomware" attacks.  We are still paying.  Indeed, a popular strategy is to pay an insurance underwriter to share some of the risk.  This is a strategy that only the underwriters and the extortioners can like.  While this was an appropriate strategy to follow early, it is no substitute for resisting and mitigating the attacks as time permits.  Has three years not been enough to address these attacks?  One would be hard pressed to make that case.  

The decision to pay is a business decision.  However, the decision to accept or assign the risk, rather than resisting or mitigating the attack, that is a security decision.  It seems clear that our plans for resisting and mitigating are not adequate and that paying the extortion is simply encouraging more attacks.  

By now every enterprise should have a plan to resist and mitigate, on a timely basis, any such attack.  If an enterprise pays a ransom, then, by definition its plan to resist and mitigate has failed.  As always an efficient plan for resisting attacks will employ layered defense.  It will include strong authentication, "least privilege" access control, and a structured network or end-to-end application layer encryption.  The measures for mitigating will include early detection, safe backup, and timely recovery of mission critical applications.  "Safe backup" will include at least three copies of all critical data, two of which are hidden from all users and at least one of which is off-site.  "Timely recovery" will include the ability to restore, not simply a file or two, but all corrupted data and critical applications within hours to days.  (While some enterprises already meat the three copy requirement, few have the capability to recover access to large quantities of data in hours to days, rather than days to weeks.)

One last observation.  If there is ransomware on your system, network, or enterprise, you have first been breached.  Hiding your data from you to extort money, is only one of the bad things that can result from the breach.  If one is vulnerable to extortion attacks, one is also vulnerable to industrial espionage, sabotage, credential and identity theft, account takeover and more.  The same measures that resist and mitigate ransomware resist and mitigate all of these other risks.

Ransomware attacks will persist as long as any significant number of victims choose to pay the ransom, as long as the value of a successful attack is greater than its cost.  The implication is that to resist attack one must increase its cost, not simply marginally but perhaps by as much as an order of magnitude.  Failure to do so is at least negligent, probably reckless.  Do, and protect, your job.  

Wednesday, June 10, 2020

On "Patching" III

One cannot patch to a secure system.

The rate of published "fixes" suggests that there is a reservoir of known and unknown vulnerabilities in these popular products (e.g., operating systems, browsers, readers, content managers). No matter how religiously one patches, the products are never whole.

They present an attack surface much larger than the applications for which they are used and cannot be relied upon to resist those attacks.  However, in part because they are standard across enterprises and applications, they are a favored target.  

They should not be exposed to the public networks. Hiding them behind firewalls and end-to-end application layer encryption moves from "good" practice to "essential."

Patching may be mandatory but it is expensive, a cost of using the product.  

On the "Expectation of Privacy"

In assessing the "search and seizure" of personal data by law enforcement, modern courts have applied the test of "reasonable expectation of privacy." This test implies that if the citizen has used his data in such a way that exposes it to others, for example, used it in a business transaction, then law enforcement may use it against them without restriction.  

The Framers never conceived of this test and might well be surprised by it.  Rather, the tests that they wrote into the Bill of Rights were "reasonable" and "probable cause."  If a search or seizure is "unreasonable," then law enforcement must have a warrant from a court.  The test for the issuance of a warrant is probable cause to believe that a crime has been, not will be, committed.  

These are constitutional tests and they are independent of how the citizen uses his personal information or what his expectations are.  He should not need to do, think, or "expect" anything in order for them to apply.  The tests apply to the behavior of the state, not the expectation of the citizen.  They restrict what the state, the police, may do.  The Bill of Rights places the burden on the state to show that its behavior is lawful, not on the citizen to demonstrate a right or "expectation."  Note that while information obtained in violation of these tests may not be used to convict the citizen of a crime, it is routinely used to investigate, threaten, and coerce, the very things that the Framers feared from a powerful government.  

In some cases, the state, with the tacit consent of the courts, pretends to get a warrant for all searches.  It pretends that it can legitimately collect anything as long as it does not look at it.  However, the Bill of Rights does not limit the tests to searches but also to "seizures." The government operates a data center in Bluffdale Utah.  In a world in which one can put a terabyte of data in one's pocket for $100, the government requires 26 acres of floor space to accommodate the data that it collects world-wide on citizens' communications.  It claims that this seizure is not "unreasonable" and that it does not need a warrant unless it "searches" or looks at the data.  By what reasoning can the arbitrary collection of so much data be called "reasonable?"

I am not hopeful that this view will be argued before the courts or that, even it argued, it will change much.  Nonetheless, I had to argue it.