![]() This includes required software & services to be running, files and folders that are protected, limited administration rights and so on. ![]() Windows Domain's are able to enforce security policies of many kinds. If you really need protection on one or more computers, you need to make them part of a Windows Domain. With regard to the second part of the question: you can't I'm afraid. A determined person would still be able to delete the file if they really wanted to. But I've no real idea if this is workable. You could try to fool Windows into adding the file into the list used by the Windows File Protection feature. Perhaps someone with better Windows security knowledge knows of a way but as far as I know, a user with Admin rights on a non-Domain (stand alone) computer can do anything they want to if they know what they are doing. AbstractCMSPage page sets ViewStateUserKey to a unique value for every user and thus prevents one click attacks.īecause ASP.NET ViewState validation and the Kentico security tokens protect the application against POST CSRF by default, only use POST requests for actions.īy default (on the level of the global web.config file), ASP.I actually can't think of a reliable way to do this as stated I'm afraid. All Kentico pages must inherit from AbstractCMSPage (the base page for all Kentico pages). The recommended value is a user's session ID. However, you can specify a key corresponding to the current user through the ViewStateUserKey page property. The problem is simple – ViewState is the same for all users. Avoiding CSRFĮven if your application uses ViewState validation and the Kentico security tokens, a special case of CSRF is still possible: one click attacks. If a page does not have these features and does not perform any actions, it also does not need to be protected against CSRF. ViewState validation helps a lot to avoid POST CSRF, so globally, we strongly recommend keeping it enabled. If you find the second string in the page directive, it means that a developer turned off ViewState validation. For example, try to find the following and similar strings in your code: If you find any page/control/etc., that performs an action on GET requests, there is a possibility of a CSRF vulnerability. For example, if the application is poorly implemented, then attackers can do anything that the victims of the attack could normally do. Vulnerability to CSRF attacks depends on individual applications and on the security of the web server. ViewState is taken from the page that can be generated after postback on that page and the validation is successful. The attacker can change the part to any other value. VIEWSTATE=/wEPDwULLTE0MDM4MzYxMjNkZIb5PxpCoDI4Dt3C2LKzz8CnHkbd&txtUserID=&btnSend=Send&_EVENTVALIDATION=/wEWAwLdr4fPBgLT8dy8BQKFzrr8AbhBL27NfMMamif/pHIFUlo41HNI But the attacker can forge a link and send it to an authorized user: ![]() Users typically insert a value into the txtUserID textbox and click the button. Protected void btnSend_Click(object sender, EventArgs e) The trick is that the attacker can use ViewState generated by ASP.NET after POST and change the values of fields and the validation will still succeed. An attacker simply sends ViewState and the values of form fields via GET. This is the reason why it is possible to perform so-called One click attacks, a special type of CSRF. ASP.NET does not take form values from Request.Form but from Request.Params.For this reason, many developers think that ASP.NET applications are bulletproof against CSRF. If ViewState is enabled, you cannot send tampered POST requests to an ASP.NET application because validation of ViewState fails. These days, almost every application provides the "keep me logged in" functionality, so this condition is easily met.ĪSP.NET complicates such attacks because of ViewState. Another condition is that the user must be logged in to a vulnerable website. So a user has to click an attacker's link or fill in an attacker's form. This is called Cross Site Request Forgery. The user then clicks the link and the action is performed without the user even noticing. An attacker can create a link for a certain action and send it to the user. A problem occurs if the web application does not check if the requests are generated by the application itself (a user clicks a link or submits a filled in form). The application typically performs some action as a result, for example, inserting of a new user into a table, deleting a forum post, etc. It either sends data via URL parameters where a HTTP GET request is used or sends data via forms where HTTP POST is used. A browser typically sends requests to web applications in one of two ways.
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