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Diffstat (limited to 'guides/source/security.md')
| -rw-r--r-- | guides/source/security.md | 26 |
1 files changed, 18 insertions, 8 deletions
diff --git a/guides/source/security.md b/guides/source/security.md index 125dd82666..184af98d65 100644 --- a/guides/source/security.md +++ b/guides/source/security.md @@ -1,3 +1,5 @@ +**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.** + Ruby on Rails Security Guide ============================ @@ -237,7 +239,7 @@ Or the attacker places the code into the onmouseover event handler of an image: <img src="http://www.harmless.com/img" width="400" height="400" onmouseover="..." /> ``` -There are many other possibilities, like using a `<script>` tag to make a cross-site request to a URL with a JSONP or JavaScript response. The response is executable code that the attacker can find a way to run, possibly extracting sensitive data. To protect against this data leakage, we disallow cross-site `<script>` tags. Only Ajax requests may have JavaScript responses since XmlHttpRequest is subject to the browser Same-Origin policy - meaning only your site can initiate the request. +There are many other possibilities, like using a `<script>` tag to make a cross-site request to a URL with a JSONP or JavaScript response. The response is executable code that the attacker can find a way to run, possibly extracting sensitive data. To protect against this data leakage, we disallow cross-site `<script>` tags. Only Ajax requests may have JavaScript responses since `XMLHttpRequest` is subject to the browser Same-Origin policy - meaning only your site can initiate the request. To protect against all other forged requests, we introduce a _required security token_ that our site knows but other sites don't know. We include the security token in requests and verify it on the server. This is a one-liner in your application controller, and is the default for newly created rails applications: @@ -247,6 +249,15 @@ protect_from_forgery with: :exception This will automatically include a security token in all forms and Ajax requests generated by Rails. If the security token doesn't match what was expected, an exception will be thrown. +NOTE: By default, Rails includes jQuery and an [unobtrusive scripting adapter for +jQuery](https://github.com/rails/jquery-ujs), which adds a header called +`X-CSRF-Token` on every non-GET Ajax call made by jQuery with the security token. +Without this header, non-GET Ajax requests won't be accepted by Rails. When using +another library to make Ajax calls, it is necessary to add the security token as +a default header for Ajax calls in your library. To get the token, have a look at +`<meta name='csrf-token' content='THE-TOKEN'>` tag printed by +`<%= csrf_meta_tags %>` in your application view. + It is common to use persistent cookies to store user information, with `cookies.permanent` for example. In this case, the cookies will not be cleared and the out of the box CSRF protection will not be effective. If you are using a different cookie store than the session for this information, you must handle what to do with it yourself: ```ruby @@ -362,7 +373,7 @@ Refer to the Injection section for countermeasures against XSS. It is _recommend **CSRF** Cross-Site Request Forgery (CSRF), also known as Cross-Site Reference Forgery (XSRF), is a gigantic attack method, it allows the attacker to do everything the administrator or Intranet user may do. As you have already seen above how CSRF works, here are a few examples of what attackers can do in the Intranet or admin interface. -A real-world example is a [router reconfiguration by CSRF](http://www.h-online.com/security/Symantec-reports-first-active-attack-on-a-DSL-router--/news/102352). The attackers sent a malicious e-mail, with CSRF in it, to Mexican users. The e-mail claimed there was an e-card waiting for them, but it also contained an image tag that resulted in a HTTP-GET request to reconfigure the user's router (which is a popular model in Mexico). The request changed the DNS-settings so that requests to a Mexico-based banking site would be mapped to the attacker's site. Everyone who accessed the banking site through that router saw the attacker's fake web site and had their credentials stolen. +A real-world example is a [router reconfiguration by CSRF](http://www.h-online.com/security/news/item/Symantec-reports-first-active-attack-on-a-DSL-router-735883.html). The attackers sent a malicious e-mail, with CSRF in it, to Mexican users. The e-mail claimed there was an e-card waiting for them, but it also contained an image tag that resulted in a HTTP-GET request to reconfigure the user's router (which is a popular model in Mexico). The request changed the DNS-settings so that requests to a Mexico-based banking site would be mapped to the attacker's site. Everyone who accessed the banking site through that router saw the attacker's fake web site and had their credentials stolen. Another example changed Google Adsense's e-mail address and password by. If the victim was logged into Google Adsense, the administration interface for Google advertisements campaigns, an attacker could change their credentials.
@@ -699,7 +710,7 @@ The log files on www.attacker.com will read like this: GET http://www.attacker.com/_app_session=836c1c25278e5b321d6bea4f19cb57e2 ``` -You can mitigate these attacks (in the obvious way) by adding the [httpOnly](http://dev.rubyonrails.org/ticket/8895) flag to cookies, so that document.cookie may not be read by JavaScript. Http only cookies can be used from IE v6.SP1, Firefox v2.0.0.5 and Opera 9.5. Safari is still considering, it ignores the option. But other, older browsers (such as WebTV and IE 5.5 on Mac) can actually cause the page to fail to load. Be warned that cookies [will still be visible using Ajax](http://ha.ckers.org/blog/20070719/firefox-implements-httponly-and-is-vulnerable-to-xmlhttprequest/), though. +You can mitigate these attacks (in the obvious way) by adding the **httpOnly** flag to cookies, so that document.cookie may not be read by JavaScript. Http only cookies can be used from IE v6.SP1, Firefox v2.0.0.5 and Opera 9.5. Safari is still considering, it ignores the option. But other, older browsers (such as WebTV and IE 5.5 on Mac) can actually cause the page to fail to load. Be warned that cookies [will still be visible using Ajax](http://ha.ckers.org/blog/20070719/firefox-implements-httponly-and-is-vulnerable-to-xmlhttprequest/), though. ##### Defacement @@ -942,7 +953,7 @@ unless params[:token].nil? end ``` -When `params[:token]` is one of: `[]`, `[nil]`, `[nil, nil, ...]` or +When `params[:token]` is one of: `[nil]`, `[nil, nil, ...]` or `['foo', nil]` it will bypass the test for `nil`, but `IS NULL` or `IN ('foo', NULL)` where clauses still will be added to the SQL query. @@ -953,9 +964,9 @@ request: | JSON | Parameters | |-----------------------------------|--------------------------| | `{ "person": null }` | `{ :person => nil }` | -| `{ "person": [] }` | `{ :person => nil }` | -| `{ "person": [null] }` | `{ :person => nil }` | -| `{ "person": [null, null, ...] }` | `{ :person => nil }` | +| `{ "person": [] }` | `{ :person => [] }` | +| `{ "person": [null] }` | `{ :person => [] }` | +| `{ "person": [null, null, ...] }` | `{ :person => [] }` | | `{ "person": ["foo", null] }` | `{ :person => ["foo"] }` | It is possible to return to old behaviour and disable `deep_munge` configuring @@ -1018,7 +1029,6 @@ Additional Resources The security landscape shifts and it is important to keep up to date, because missing a new vulnerability can be catastrophic. You can find additional resources about (Rails) security here: -* The Ruby on Rails security project posts security news regularly: [http://www.rorsecurity.info](http://www.rorsecurity.info) * Subscribe to the Rails security [mailing list](http://groups.google.com/group/rubyonrails-security) * [Keep up to date on the other application layers](http://secunia.com/) (they have a weekly newsletter, too) * A [good security blog](http://ha.ckers.org/blog/) including the [Cross-Site scripting Cheat Sheet](http://ha.ckers.org/xss.html) |