Category Archives: Security

How to Trace an Email Message

email iconThere is no way to verify an email’s contents except through cryptography. Until every email client includes encryption and reliable authentication, we should always doubt an email’s source.

We can increase our confidence in an email a little, though, by tracing its path through the mail system. I use this technique more-or-less daily to look at potential phishing emails. If the final Received header didn’t come from my bank, then I know it’s fake.

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HR and Phishing

UMN phishing exampleI receive thousands of emails every month. I do a lot of (for me) critical activities online. I never receive legitimate emails demanding a suspicious online action any more.

Except from HR departments.

IT security people know this is a problem. The upper left image comes from the University of Minnesota’s phishing awareness blog. HR people as individuals also seem to know that phishing is a problem. But they still insist on sending suspicious-looking emails that demand personal information. No doubt it saves their department a few dollars.

Full disclosure: as noted at the end of this posting, Minnesota’s HR department has taken several steps to reduce these risks.

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The Six Types of Cyber-Risks

BombMy textbook lists categories of cyber-attacks that focus on an attack’s lasting impact: how does it affect the target’s assets and resources? Since the categories really reflect the attack’s impact on the target, they really represent risks. Here are the categories I use right now:

Denial of service – Pillage – Subversion

Masquerade – Forgery – Disclosure

This is a work in progress as I figure out some conceptual ideas.

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Quantum Skepticism

img_0540-1Quantum computing gives us a way in theory to quickly crack certain types of cryptography. Well-funded startups are working on prototype quantum circuits, as are big guns like Intel, Microsoft, and IBM. Success could render a lot of today’s encryption obsolete. In theory.

Academic and industrial research labs have built basic quantum circuits. If Moore’s Law applies to quantum circuits, they will be the next big thing.

I remain skeptical. Quantum computing seems like perpetual motion machines to me, though I’ve never researched reasons to support my intuition. Researcher Gil Kalai presents an argument based on computational theory and models of noise. He argues that practical computations will lose out to noise effects. I’ll be interested to see more about this.

The Big Bug in the News: the WPA2 flaw

Wi Fi signal graphicThe big news this week is a protocol flaw in the Wireless Protected Access protocol, version 2 (WPA2). The Ars Technica article covers the details pretty well. This is what every Wi-Fi wireless router on the planet uses these days. The problem does not directly damage your system, but it can uncover data you had intended to encrypt.

The technique can trick the system into reusing a cryptographic key. To keep encrypted data safe we must avoid encrypting the same data twice (here’s an example of how it fails). While crypto system designs usually account for this, the attack on WPA2 tricks the system into reusing the key.

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Comparing Leaks: Trump vs. Hillary

Lattice for Secret, Top Secret, and compartmentsAs I said in an earlier post, no crime is committed if the appropriate official leaks sensitive classified information. This applies to both Secretary Clinton’s email server and President Trump’s unfortunate meeting with Russian diplomats. Both carried the authority to disclose what they disclosed. One question remains: what damage might have ensued from each leak?

I would argue that in both cases the initial lapse of judgement did not explicitly damage the United States. In both cases, however, the subsequent brouhaha may have leaked classified information. I personally doubt that the country will suffer much from either leak, though that is based on my own assessment of national threats (a political opinion).

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Tiptoeing Through Vulnerabilities

BombI sympathize with developers who throw up their hands and say, “I don’t do security stuff.” No matter what you choose, there’s a trade off that could go wrong. It’s especially troublesome if one deploys a “security website.” I’ve deployed security education websites in many environments over the past 20 years, and I rarely achieve the security level I’d like.

I wanted to watch a security webinar today.  But the webinar requires Adobe Flash, in which security researchers seem to uncover 1 or 2 vulnerabilities a month. I discarded Flash when upgrading my OS a couple years ago. It’s ironic that a security webinar might tempt it back onto my machine.

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Cryptosmith Video Series

Banner for Transport Layer Security videoThe Cryptosmith video series uses animation to explain well-known crypto techniques. This should help more people understand crypto technology. This is particularly important as people rely more and more on mobile and Internet security mechanisms. Aside from protecting online commerce and financial activities, many professionals are realizing that their daily activities require strong protection.

[UPDATE: See the latest post to summarize the video series.]

After publishing three books on cybersecurity and cryptography I’m looking for a different medium for explaining technical concepts. While there are many online tutorial videos, most are narrated slide presentations. I’m trying something else.

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#PodestaEmails are NOT obvious fakes

Wikileaks globe-hourglass logoEmails are notoriously hard to validate. Emails are like typed, signed contracts with no section or page numbers: you can take out or add whatever pages you want as long as you keep the signatures.

Intelligence expert Malcom Nance has tweeted that Wikileaks’ recent collection of Podesta emails contain “obvious forgeries.” It is hard to detect emails forgeries in general, but easy to find obvious forgeries. For details, check out Chapter 15 of Elementary Information Security, my textbook.

I searched recent news reports highlighting specific Podesta emails. I looked at about a dozen of those emails, plus similar “unimportant” emails. I checked the email delivery data for tampering or forgery. The email headers look correct. Thus there are no “obvious forgeries.”

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