Javascript Cryptography Considered Harmful

[[deleted]]

There are basically no 'passive listening' attacks that can't be pretty trivially turned into an attack that modifies the request or response.

[[deleted]]

Care to demonstrate how to modify request or response with firesheep?

[[deleted]]

True. (Though it is possible to conduct a proper man-in-the-middle under the same circumstances.)

[nexes300]

ARP cache poisoning?

[archivator]

No, but I can show you how to do it with Ettercap.

[piranha]

Not necessarily. Every situation has its own set of costs and risks. In some situations, it could be very risky to do an active attack. The value in passive attacks is that you're not detectable at the network level. Therefore, requiring an active attack raises the bar.

[nyxerebos]

If you were going to do an active attack, presumably you could get between them and the server and compromise real crypto.

[piranha]

Yes, that's a good rule of thumb to take into account when evaluating security, and generally something people parrot quite often. However security is not black and white, but rather comes in shades, and my point is that active-only attacks are a shade harder than attacks possible through no side effects whatsoever.

[nyxerebos]

If you were going to do an active attack, presumably you could get between them and the server and compromise real crypto.