Simon Willison’s Weblog

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Items tagged security, cookies

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Exploring the SameSite cookie attribute for preventing CSRF

In reading Yan Zhu’s excellent write-up of the JSON CSRF vulnerability she found in OkCupid one thing puzzled me: I was under the impression that browsers these days default to treating cookies as SameSite=Lax, so I would expect attacks like the one Yan described not to work in modern browsers.

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Firesheep (via) Oh wow. A Firefox extension that makes sniffing for insecured (non-HTTPS) cookie requests on your current WiFi network and logging in as that person a case of clicking a couple of buttons. Always possible of course, but it’s never been made easy before. Private VPNs are about to become a lot more popular. # 25th October 2010, 9:11 am

Django ponies: Proposals for Django 1.2

I’ve decided to step up my involvement in Django development in the run-up to Django 1.2, so I’m currently going through several years worth of accumulated pony requests figuring out which ones are worth advocating for. I’m also ensuring I have the code to back them up—my innocent AutoEscaping proposal a few years ago resulted in an enormous amount of work by Malcolm and I don’t think he’d appreciate a repeat performance.

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Adding signing (and signed cookies) to Django core. I’ve been increasing my participation in Django recently—here’s my proposal for adding signing and signed cookies to Django, which I’d personally like to see ship as part of Django 1.2. # 24th September 2009, 7:31 pm

You Deleted Your Cookies? Think Again (via) Flash cookies last longer than browser cookies and are harder to delete. Some services are sneakily “respawning” their cookies—if you clear the regular tracking cookie it will be reinstated from the Flash data next time you visit a page. # 17th August 2009, 3:23 pm

Django snippets: Sign a string using SHA1, then shrink it using url-safe base65. I needed a way to create tamper-proof URLs and cookies by signing them, but didn’t want the overhead of a full 40 character SHA1 hash. After some experimentation, it turns out you can knock a 40 char hash down to 27 characters by encoding it using a custom base65 encoding which only uses URL-safe characters. # 27th August 2008, 10:18 pm

Site-specific browsers and GreaseKit. New site-specific browser tool which lets you include a bunch of Greasemonkey scripts. For me, the killer feature of site-specific browsers is still cookie isolation (to minimise the impact of XSS and CSRF holes) but none of the current batch of tools advertise this as a feature, and most seem to want to share the system-wide cookie jar. # 25th October 2007, 7:56 am

Currently WebRunner applications share cookies with other WebRunner applications, but not with Firefox. WebRunner uses its own profile, not Firefox’s profile. There is a plan to allow WebRunner applications to create their own, private profiles as well.

Mark Finkle # 30th September 2007, 4:08 pm

IE vulnerability allows cookie stealing. Full exploit against the same-domain cookie origin policy, so malicious sites can steal cookies from elsewhere. Avoid using IE until this is patched. # 6th June 2007, 9:53 am