December 15, 2007

MITM spotted in Tor

Bruce Schneier wrote in cryptogram:

Man-in-the-middle attack by Tor exit node. So often man-in-the-middle attacks are theoretical; it's fascinating to see one in the wild. The guy claims that he just misconfigured his Tor node. I don't know enough about Tor to have any comment about this. [German commetary.] I've written about anonymity and the Tor network before.

Can't agree more! MITMs are so rare that they really should not drive any threat model until shown to be economic. Making that mistake was one of the core failures that led to phishing (thanks guys!). Here's a more simple sniffing attack on the same network:

I previously wrote about Dan Egerstad, a security researcher who ran a Tor anonymity network and was able to sniff some pretty impressive usernames and passwords. Swedish police arrested him last month.

Pure eavesdropping is also worth recording because we need to establish the frequency so as to calculate how much attention to pay to it. For the interest of financial cryptographers here, let's add this one from the same source, pointing to BoingBoing pointing to b.wsj:

In 1941, the British Secret Service asked the game's British licensee John Waddington Ltd. to add secret extras to some sets, which had become standard elements of the aid packages that the Red Cross delivered to allied prisoners of war. Along with the usual dog, top hat and and thimble, the sets had a metal file, compass, and silk maps of safe houses (silk, because it folds into small spaces and unfolds silently). Even better, real French, German and Italian currency was hidden underneath the game's fake money. Departing allied soldiers and pilots were told that if they were captured they should look out for the special editions, identified by a red dot in the Free Parking space. Any sets remaining in the U.K. were destroyed after the war. Of the 35,000 prisoners of war who escaped German prison camps by the end of the war, "more than a few of those certainly owe their breakout to the classic board game," says Mr. McMahon.
Posted by iang at December 15, 2007 08:10 AM | TrackBack

for topic drift ... i mention here

in a thread about using on-screen visual keyboards (CAPTHAs obscured)

and mouse clicks as countermeasure to PC virus/trojans capturing online banking userid/passwords.

this is PC virus/trojan that waits until the session has been initiated ... and then executes fraudulent transactions w/o the person's knowledge

New Trojan Attacks Clients At Four Worldwide Banks
Sophisticated Trojan loots business bank accounts
Botnet-controlled Trojan robbing online bank customers

the original thread had drifted into topic that the threats/vulnerabilities had been well-studied and understood by at least the mid-90s ... along with the current spate of kneejerk, simple-minded, point solutions for each individual exploit that appears, rather than addressing underlying infrastructure weaknesses.

in the case of the online banking visual keyboard scenario ... it is obviously a countermeasure to compromised PC ... then where does it say that a ompromised PC will only be limited to keylogging.

one could claim that the original SSL design (before the mid-90s) was countermeasure to hostile environment ... not only did the session have to be authenticated ... but everything related to the session had to also be armored.

if the environment is really hostile, then it is much better going to individual armored transaction instead of assuming that everything within a session boundary is secure ... somewhat discussed in old thread here last summer on naked transactions

comments about the culture of kneejerk simple-minded point-solution reaction to exploits Securing financial transactions a high priority for 2007 John W. Backus, 82, Fortran developer, dies open source voting My Dream PC -- Chip-Based IBM 8000 series folklore indeed folklore indeed folklore indeed folklore indeed folklore indeed folklore indeed folklore indeed

Posted by: Lynn Wheeler at December 15, 2007 11:05 AM
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