在大多数现代单页应用程序中，我们确实必须将令牌存储在客户端某处(最常见的用例——在页面刷新后保持用户登录)。

总共有2个选项可用:Web Storage(会话存储，本地存储)和客户端cookie。这两种方法都被广泛使用，但这并不意味着它们非常安全。

Tom Abbott很好地总结了JWT sessionStorage和localStorage安全性:

Web Storage (localStorage/sessionStorage) is accessible through JavaScript on the same domain. This means that any JavaScript running on your site will have access to web storage, and because of this can be vulnerable to cross-site scripting (XSS) attacks. XSS, in a nutshell, is a type of vulnerability where an attacker can inject JavaScript that will run on your page. Basic XSS attacks attempt to inject JavaScript through form inputs, where the attacker puts <script>alert('You are Hacked');</script> into a form to see if it is run by the browser and can be viewed by other users.

为了防止XSS，常见的响应是转义和编码所有不可信的数据。React(主要)为您做这些!这里有一个关于React在多大程度上负责XSS漏洞保护的很好的讨论。

但这并没有涵盖所有可能的漏洞!另一个潜在威胁是JavaScript托管在cdn或外部基础设施上的使用。

汤姆说:

Modern web apps include 3rd party JavaScript libraries for A/B testing, funnel/market analysis, and ads. We use package managers like Bower to import other peoples’ code into our apps. What if only one of the scripts you use is compromised? Malicious JavaScript can be embedded on the page, and Web Storage is compromised. These types of XSS attacks can get everyone’s Web Storage that visits your site, without their knowledge. This is probably why a bunch of organizations advise not to store anything of value or trust any information in web storage. This includes session identifiers and tokens.

因此，我的结论是，作为一种存储机制，Web storage在传输过程中没有强制执行任何安全标准。任何阅读Web Storage并使用它的人都必须尽职尽责，以确保始终通过HTTPS而不是HTTP发送JWT。

localStorage和httpOnly cookie都不能接受吗?关于一个妥协的第三方库，我所知道的唯一能减少/防止敏感信息被窃取的解决方案是强制执行子资源完整性。

子资源完整性(SRI)是一种安全特性 浏览器验证它们获取的资源(例如从CDN) 交付时没有意外的操作。它通过允许 您可以提供所获取资源必须的加密散列 匹配。

只要受感染的第三方库在您的网站上是活跃的，键盘记录程序就可以开始收集信息，如用户名，密码，以及您输入到网站的任何其他内容。

httpOnly cookie将阻止来自另一台计算机的访问，但不会阻止黑客操纵用户的计算机。

基本上可以将JWT存储在localStorage中。

我认为这是一个好方法。 如果我们谈论的是XSS, XSS使用CDN，这也是一个潜在的风险，获得您客户的登录/通行证。将数据存储在本地至少可以防止CSRF攻击。

你需要了解这两点，然后选择你想要的。这两种攻击都不是你所需要注意的，只要记住:你的整个应用程序的安全性仅与你的应用程序的最不安全的点一样。

再次重申，存储是OK的，易受XSS, CSRF，…不是

Localstorage被设计成可以通过javascript访问，所以它不提供任何XSS保护。正如在其他回答中提到的，有很多可能的方式来进行XSS攻击，默认情况下，本地存储不受保护。

However, cookies have security flags which protect from XSS and CSRF attacks. HttpOnly flag prevents client side javascript from accessing the cookie, Secure flag only allows the browser to transfer the cookie through ssl, and SameSite flag ensures that the cookie is sent only to the origin. Although I just checked and SameSite is currently supported only in Opera and Chrome, so to protect from CSRF it's better to use other strategies. For example, sending an encrypted token in another cookie with some public user data.

因此，cookie是存储身份验证数据的更安全的选择。

在大多数现代单页应用程序中，我们确实必须将令牌存储在客户端某处(最常见的用例——在页面刷新后保持用户登录)。

总共有2个选项可用:Web Storage(会话存储，本地存储)和客户端cookie。这两种方法都被广泛使用，但这并不意味着它们非常安全。

Tom Abbott很好地总结了JWT sessionStorage和localStorage安全性:

Web Storage (localStorage/sessionStorage) is accessible through JavaScript on the same domain. This means that any JavaScript running on your site will have access to web storage, and because of this can be vulnerable to cross-site scripting (XSS) attacks. XSS, in a nutshell, is a type of vulnerability where an attacker can inject JavaScript that will run on your page. Basic XSS attacks attempt to inject JavaScript through form inputs, where the attacker puts <script>alert('You are Hacked');</script> into a form to see if it is run by the browser and can be viewed by other users.

为了防止XSS，常见的响应是转义和编码所有不可信的数据。React(主要)为您做这些!这里有一个关于React在多大程度上负责XSS漏洞保护的很好的讨论。

但这并没有涵盖所有可能的漏洞!另一个潜在威胁是JavaScript托管在cdn或外部基础设施上的使用。

汤姆说:

Modern web apps include 3rd party JavaScript libraries for A/B testing, funnel/market analysis, and ads. We use package managers like Bower to import other peoples’ code into our apps. What if only one of the scripts you use is compromised? Malicious JavaScript can be embedded on the page, and Web Storage is compromised. These types of XSS attacks can get everyone’s Web Storage that visits your site, without their knowledge. This is probably why a bunch of organizations advise not to store anything of value or trust any information in web storage. This includes session identifiers and tokens.

因此，我的结论是，作为一种存储机制，Web storage在传输过程中没有强制执行任何安全标准。任何阅读Web Storage并使用它的人都必须尽职尽责，以确保始终通过HTTPS而不是HTTP发送JWT。

Philippe De Ryck博士写了一篇有用的文章，深入分析了漏洞(尤其是XSS)的真正影响。

这篇文章让人大开眼界!

简而言之，开发人员最关心的应该是保护web应用程序不受XSS的影响，而不应该太担心使用哪种类型的存储区域。

菲利普医生建议采取以下3个步骤:

Don't worry too much about the storage area. Saving an access token in localStorage area will save the developer a massive amount of time for development of next phases of the application. Review your app for XSS vulnerabilities. Perform a through code review and learn how to avoid XSS within the scope of your templating framework. Build a defense-in-depth mechanism against XSS. Learn how you could further lock down your application. E.g. utilising Content Security Policy (CSP) and HTML5 sandboxing.

记住，一旦你被XSS攻击了，游戏就结束了!