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Difference between revisions of "Top 10 2017-A8-Cross-Site Request Forgery (CSRF)"
(Launch the new page for Top 10 2017-A8-Cross-Site Request Forgery (CSRF) (RC1) with content of 2013-A8 as a reference to compare changes) |
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| − | Consider anyone who can load content into your users’ browsers, and thus force them to submit a request to your website. Any website or other HTML feed that your users access could do this. | + | <!--- Threat Agents: --->Consider anyone who can load content into your users’ browsers, and thus force them to submit a request to your website. Any website or other HTML feed that your users access could do this. |
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| − | Attacker creates forged HTTP requests and tricks a victim into submitting them via image tags, XSS, or numerous other techniques. <u>If the user is authenticated</u>, the attack succeeds. | + | <!--- Attack Vectors --->Attacker creates forged HTTP requests and tricks a victim into submitting them via image tags, XSS, or numerous other techniques. <u>If the user is authenticated</u>, the attack succeeds. |
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| − | <td colspan=2 {{Template:Top 10 2010:SummaryTableRowStyleTemplate|year=2017}}>[https://www.owasp.org/index.php/CSRF CSRF] takes advantage the fact that most web apps allow attackers to predict all the details of a particular action. | + | <td colspan=2 {{Template:Top 10 2010:SummaryTableRowStyleTemplate|year=2017}}> |
| + | <!--- Security Weakness --->[https://www.owasp.org/index.php/CSRF CSRF] takes advantage the fact that most web apps allow attackers to predict all the details of a particular action. | ||
Because browsers send credentials like session cookies automatically, attackers can create malicious web pages which generate forged requests that are indistinguishable from legitimate ones. | Because browsers send credentials like session cookies automatically, attackers can create malicious web pages which generate forged requests that are indistinguishable from legitimate ones. | ||
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| − | Attackers can trick victims into performing any state changing operation the victim is authorized to perform, e.g., updating account details, making purchases, logout and even login. | + | <!--- Technical Impacts --->Attackers can trick victims into performing any state changing operation the victim is authorized to perform, e.g., updating account details, making purchases, logout and even login. |
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| − | Consider the business value of the affected data or application functions. Imagine not being sure if users intended to take these actions. | + | <!--- Business Impacts --->Consider the business value of the affected data or application functions. Imagine not being sure if users intended to take these actions. |
Consider the impact to your reputation. | Consider the impact to your reputation. | ||
Revision as of 09:26, 22 April 2017
| ← A7-Cross-Site Scripting (XSS) | A9-Using Components with Known Vulnerabilities → |
| Threat Agents / Attack Vectors | Security Weakness | Impacts | |||
|---|---|---|---|---|---|
| App Specific | Exploitability AVERAGE |
Prevalence COMMON |
Detectability EASY |
Impact MODERATE |
Business ? |
|
Consider anyone who can load content into your users’ browsers, and thus force them to submit a request to your website. Any website or other HTML feed that your users access could do this. |
Attacker creates forged HTTP requests and tricks a victim into submitting them via image tags, XSS, or numerous other techniques. If the user is authenticated, the attack succeeds. |
CSRF takes advantage the fact that most web apps allow attackers to predict all the details of a particular action. Because browsers send credentials like session cookies automatically, attackers can create malicious web pages which generate forged requests that are indistinguishable from legitimate ones. Detection of CSRF flaws is fairly easy via penetration testing or code analysis. |
Attackers can trick victims into performing any state changing operation the victim is authorized to perform, e.g., updating account details, making purchases, logout and even login. |
Consider the business value of the affected data or application functions. Imagine not being sure if users intended to take these actions. Consider the impact to your reputation. |
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Am I Vulnerable To 'Insecure Deserialization'?
To check whether an application is vulnerable, see if any links and forms lack an unpredictable CSRF token. Without such a token, attackers can forge malicious requests. An alternate defense is to require the user to prove they intended to submit the request, either through reauthentication, or some other proof they are a real user (e.g., a CAPTCHA). Focus on the links and forms that invoke state-changing functions, since those are the most important CSRF targets. You should check multistep transactions, as they are not inherently immune. Attackers can easily forge a series of requests by using multiple tags or possibly JavaScript. Note that session cookies, source IP addresses, and other information automatically sent by the browser don’t provide any defense against CSRF since this information is also included in forged requests. OWASP’s CSRF Tester tool can help generate test cases to demonstrate the dangers of CSRF flaws. |
How Do I Prevent 'Insecure Deserialization'?
Preventing CSRF usually requires the inclusion of an unpredictable token in each HTTP request. Such tokens should, at a minimum, be unique per user session.
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Example Attack Scenarios
The application allows a user to submit a state changing request that does not include anything secret. For example: http://example.com/app/transferFunds?amount=1500&destinationAccount=4673243243 So, the attacker constructs a request that will transfer money from the victim’s account to the attacker’s account, and then embeds this attack in an image request or iframe stored on various sites under the attacker’s control: <img src="http://example.com/app/transferFunds?amount=1500&destinationAccount=attackersAcct#" width="0" height="0" /> If the victim visits any of the attacker’s sites while already authenticated to example.com, these forged requests will automatically include the user’s session info, authorizing the attacker’s request.
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References
OWASP
External |
| ← A7-Cross-Site Scripting (XSS) | A9-Using Components with Known Vulnerabilities → |
