简单看下最近的Spring Secrurity、Spring漏洞（CVE-2024-22234、CVE-2024-22243）

来源：cnblogs　　作者：9eek　　时间：2024/2/28 9:08:19　　对本文有异议

最近的这两个cve我看国内很多情报将其评为高危，所以想着去看看原理，看完发现都比较简单，利用要求的场景也相对有限(特别是第一个)，所以就随便看下就行了

Spring Security 用户认证绕过(CVE-2024-22234)

先看下官网的公告（https://spring.io/security/cve-2024-22234）

In Spring Security, versions 6.1.x prior to 6.1.7 and versions 6.2.x prior to 6.2.2, an application is vulnerable to broken access control when it directly uses the AuthenticationTrustResolver.isFullyAuthenticated(Authentication) method.

Specifically, an application is vulnerable if:

The application uses AuthenticationTrustResolver.isFullyAuthenticated(Authentication) directly and a null authentication parameter is passed to it resulting in an erroneous true return value.

An application is not vulnerable if any of the following is true:

The application does not use AuthenticationTrustResolver.isFullyAuthenticated(Authentication) directly.

The application does not pass null to AuthenticationTrustResolver.isFullyAuthenticated

The application only uses isFullyAuthenticated via Method Security or HTTP Request Security

大概意思是直接调用``AuthenticationTrustResolver.isFullyAuthenticated(Authentication)` ，若Authentication为null，则方法会永远返回真，从而产生一些与预期相反的结果。

AuthenticationTrustResolver 接口中的 isFullyAuthenticated 方法用于检查 Authentication 对象是否完全经过身份验证，即是否不是匿名用户。在 Spring Security 中，可以使用这个方法来确定用户是否已经进行了完整的身份验证。

影响版本为：

6.1.0 to 6.1.6
6.2.0 to 6.2.1

环境搭建

引入pom，实际调用：

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-security</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-test</artifactId>
    <scope>test</scope>
</dependency>

增加下密码验证和/index的无鉴权的配置（交给应用手动配置）

@Configuration
@EnableWebSecurity
public class WebSecurityConfig {
    @Bean
    public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {
        http
                .authorizeHttpRequests((requests) -> requests
                        .requestMatchers("/", "/index").permitAll()  // 端点/、/index 无需鉴权，交给应用直接控制
                        .anyRequest().authenticated()
                )
                .formLogin((form) -> form
                        .loginPage("/login")
                        .permitAll()
                )
                .logout((logout) -> logout.permitAll());
        return http.build();
    }
    @Bean
    public UserDetailsService userDetailsService() {
        UserDetails user =
                User.withDefaultPasswordEncoder()
                        .username("user")
                        .password("password")
                        .roles("USER")
                        .build();
        return new InMemoryUserDetailsManager(user);
    }
}

新增控制器并配置需要用户手动输入密码（isFullyAuthenticated）后才能访问的逻辑：

    @GetMapping("/index")
    @ResponseBody
    public String index(){
        // CVE-2024-22234
        // 获取当前的认证对象
        Authentication authentication = SecurityContextHolder.getContext().getAuthentication();
        System.out.println(authentication);
        // 创建 AuthenticationTrustResolver 实例
        AuthenticationTrustResolver trustResolver = new AuthenticationTrustResolverImpl();
        // 使用 isFullyAuthenticated 方法检查是否完全经过身份验证
        boolean fullyAuthenticated = trustResolver.isFullyAuthenticated(authentication);  // 传递null返回即为true
        String msg = "";
        if (fullyAuthenticated) {
            msg = "用户已完全经过身份验证";
        } else {
            msg = "用户可能是匿名用户或者仅部分经过身份验证";
        }
        return msg;
    }

复现

正常情况下，如果没有经过认证，返回的页面为：

进入登录页面正常登录后

返回的页面为：

如果开发在某些情况，比如手动清除SecurityContextHolder中的Authentication信息或通过异步处理导致在异步线程中没有可用的信息getAuthentication()返回null, 则会导致认证校验的失效，我们这里为了复现就手动置为null，

boolean fullyAuthenticated = trustResolver.isFullyAuthenticated(null);

重启应用，在不登陆的情况下，重新访问/index ，发现isFullyAuthenticated已经直接返回了true 。访问鉴权后的页面

![image-20240227115847155](/Users/shellfeel/Library/Application Support/typora-user-images/image-20240227115847155.png)

修复

修复方式也比较简单在isFullyAuthenticated 中增加了对authentication对象为空的判断

Spring Framework SSRF or open redirect( CVE-2024-22243)

Applications that use UriComponentsBuilder to parse an externally provided URL (e.g. through a query parameter) AND perform validation checks on the host of the parsed URL may be vulnerable to a open redirect attack or to a SSRF attack if the URL is used after passing validation checks.

这个看官网描述只知道使用UriComponentsBuilder这个方法来做host校验，会导致重定向和ssrf，粗看下源码不知道是怎么回事，看了下代码更新记录，很简单只是将uri匹配中userinfo匹配的正则表达式去掉[。

pre：

private static final String USERINFO_PATTERN = "([^@\\[/?#]*)";

now:

private static final String USERINFO_PATTERN = "([^@/?#]*)";

环境搭建

这里假设存在一个场景，后端会将用户输入的url交给UriComponentsBuilder进行验证，通过后进行正常的访问，后端有个简单的黑名单host判断（evil.com）：

String url = "http://xxx.com";
UriComponents uriComponents = UriComponents uriComponents = UriComponentsBuilder.fromUriString(url).build();
String host = uriComponents.getHost();
System.out.println("userinfo: " + uriComponents.getUserInfo());
System.out.println("host: " + host);
// 如果host为 evil.com 则会被拦截
if (host != null && host.equals("evil.com")) {
    System.out.println("403");
}else {
    System.out.println("pass");
}