Nitesh Dhanjani released his research on issues within Apple’s Safari browser today.
Apprantly Apple has decided not to fix two of the issues and gave Dhanjani permission to discuss them with the security community.
1. Safari Carpet Bomb. It is possible for a rogue website to litter the user’s Desktop (Windows) or Downloads directory (~/Downloads/ in OSX). This can happen because the Safari browser cannot be configured to obtain the user’s permission before it downloads a resource. Safari downloads the resource without the user’s consent and places it in a default location (unless changed).
The implication of this is obvious: Malware downloaded to the user’s desktop without the user’s consent.
Apple does not feel this is a issue they want to tackle at this time. In my most recent email to Apple, I suggested that they incorporate an option in Safari so the browser can be configured to ask the user before anything is downloaded to the local file system. Apple agreed it was a good suggestion:
…the ability to have a preference to “Ask me before downloading anything” is a good suggestion. We can file that as an enhancement request for the Safari team. Please note that we are not treating this as a security issue, but a further measure to raise the bar against unwanted downloads. This will require a review with the Human Interface team. We want to set your expectations that this could take quite a while, if it ever gets incorporated.
[credit to BK have-it-your-way Rios for suggesting the term "Carpet Bomb" to describe this issue].
2. Sandbox not Applied to Local Resources. This issue is more of a feature set request than a vulnerability. For example, Internet Explorer warns users when a local resource such as an HTML file attempts to invoke client side scripting. I feel this is an important security feature because of user expectations: even the most sophisticated users differentiate between the risk of clicking on an executable they have downloaded (risk perceived to be higher) to clicking on a HTML file they have downloaded (risk perceived to be lower).
Apple’s response was positive:
…we have been investigating the potential for a “safe” mode for local HTML. This is an area that requires a fairly deep investigation to address compatibility issues, and to determine the proper operation. Please understand that when we label this as a security hardening measure, we are not discounting the benefits that this could have.
http://www.dhanjani.com/archives/2008/05/safari_carpet_bomb.html
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