{"id":16050,"date":"2016-10-13T16:48:38","date_gmt":"2016-10-13T20:48:38","guid":{"rendered":"http:\/\/mjtsai.com\/blog\/?p=16050"},"modified":"2020-12-24T11:57:51","modified_gmt":"2020-12-24T16:57:51","slug":"favicon-ico-is-a-privacy-leak","status":"publish","type":"post","link":"https:\/\/mjtsai.com\/blog\/2016\/10\/13\/favicon-ico-is-a-privacy-leak\/","title":{"rendered":"favicon.ico Is a Privacy Leak"},"content":{"rendered":"<p><a href=\"https:\/\/robinlinus.github.io\/socialmedia-leak\/\">Robin Linus<\/a> (via <a href=\"https:\/\/twitter.com\/codinghorror\/status\/786259854235009024\">Jeff Atwood<\/a>):<\/p>\n<blockquote cite=\"https:\/\/robinlinus.github.io\/socialmedia-leak\/\"><p>For most web platforms there&rsquo;s a way to abuse the login mechanism to detect whether a user is logged in to that service.<\/p>\n<p>[&#8230;]<\/p>\n<p>Well, the [Same Origin Policy] is strict for HTML pages, but it allows to receive images from other origins! So if the resource in the <code>next<\/code> parameter would be an image we could read it from our website. It can&rsquo;t be any image though. Facebook checks if the URL in the <code>next<\/code> parameter starts with <code>https:\/\/facebook.com<\/code>. So we need to find an image on facebook.com. Should be easy, right? Actually it isn&rsquo;t, because facebook hosts almost all images on their CDN servers under the domain <code>fbcdn.net<\/code>. Though there is one image that you can find on almost every webserver: the good old <code>favicon.ico<\/code>!<\/p><\/blockquote>","protected":false},"excerpt":{"rendered":"<p>Robin Linus (via Jeff Atwood): For most web platforms there&rsquo;s a way to abuse the login mechanism to detect whether a user is logged in to that service. [&#8230;] Well, the [Same Origin Policy] is strict for HTML pages, but it allows to receive images from other origins! So if the resource in the next [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"apple_news_api_created_at":"2020-12-24T16:57:53Z","apple_news_api_id":"a2f4b312-b490-47f3-8f5d-7441df6a8c2c","apple_news_api_modified_at":"2020-12-24T16:57:54Z","apple_news_api_revision":"AAAAAAAAAAD\/\/\/\/\/\/\/\/\/\/w==","apple_news_api_share_url":"https:\/\/apple.news\/AovSzErSQR_OPXXRB32qMLA","apple_news_coverimage":0,"apple_news_coverimage_caption":"","apple_news_is_hidden":false,"apple_news_is_paid":false,"apple_news_is_preview":false,"apple_news_is_sponsored":false,"apple_news_maturity_rating":"","apple_news_metadata":"\"\"","apple_news_pullquote":"","apple_news_pullquote_position":"","apple_news_slug":"","apple_news_sections":"\"\"","apple_news_suppress_video_url":false,"apple_news_use_image_component":false,"footnotes":""},"categories":[2],"tags":[2026,355,96],"class_list":["post-16050","post","type-post","status-publish","format-standard","hentry","category-technology","tag-favicons","tag-privacy","tag-web"],"apple_news_notices":[],"_links":{"self":[{"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/posts\/16050","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/comments?post=16050"}],"version-history":[{"count":1,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/posts\/16050\/revisions"}],"predecessor-version":[{"id":16051,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/posts\/16050\/revisions\/16051"}],"wp:attachment":[{"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/media?parent=16050"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/categories?post=16050"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/tags?post=16050"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}