Linux下EDR产品设计：高危命令阻断<\/h1>

概述<\/h2>
本文档详细介绍了在Linux环境下设计EDR(终端检测与响应)产品中高危命令阻断功能的实现方法。该功能主要通过eBPF技术监控和阻断危险系统命令的执行，如`rm<\/code>和killall<\/code>等可能对系统造成破坏的操作。<\/p>`

技术实现<\/h2>
1. 产品对比<\/h3>
在实现高危命令阻断功能前，需要对不同EDR产品方案进行对比评估：<\/p>

1号产品服务<\/strong>：提供基础命令监控功能<\/li>
2号产品服务<\/strong>：提供更全面的命令阻断和审计功能<\/li>
<\/ul>
2. 核心组件<\/h3>
Probe & Kprobe<\/h4>
使用Linux内核的kprobe机制来监控系统调用：<\/p>

kprobe允许在内核函数执行前后插入钩子<\/li>
可以捕获系统调用的参数和返回值<\/li>
特别关注execve<\/code>系统调用，这是命令执行的关键入口<\/li>
<\/ul>
3. 设计流程<\/h3>


部署准备<\/strong>：<\/p>

确认系统支持eBPF<\/li>
安装必要的开发工具和内核头文件<\/li>
<\/ul>
<\/li>

eBPF程序开发<\/strong>：<\/p>

编写内核态eBPF代码<\/li>
实现命令匹配逻辑<\/li>
设计阻断机制<\/li>
<\/ul>
<\/li>

用户态程序开发<\/strong>：<\/p>

编写与eBPF程序交互的用户态代码<\/li>
实现日志记录和报警功能<\/li>
<\/ul>
<\/li>

系统集成<\/strong>：<\/p>

将程序打包为系统服务<\/li>
配置自动启动<\/li>
<\/ul>
<\/li>
<\/ol>
4. 具体实现步骤<\/h3>
安装eBPF依赖<\/h4>
# 安装必要的开发工具<\/span>
<\/span><\/span>sudo apt-get install -y build-essential git make libelf-dev clang llvm
<\/span><\/span>
<\/span><\/span># 安装内核头文件<\/span>
<\/span><\/span>sudo apt-get install -y linux-headers-$(<\/span>uname -r)<\/span>
<\/span><\/span><\/code><\/pre>eBPF代码实现（以rm & killall为例）<\/h4>
\/\/ block_execve.c
<\/span><\/span><\/span><\/span>#include<\/span> <linux\/bpf.h><\/span>
<\/span><\/span><\/span>#include<\/span> <linux\/version.h><\/span>
<\/span><\/span><\/span>#include<\/span> <linux\/ptrace.h><\/span>
<\/span><\/span><\/span>#include<\/span> <linux\/sched.h><\/span>
<\/span><\/span><\/span>#include<\/span> <linux\/fs.h><\/span>
<\/span><\/span><\/span>#include<\/span> <uapi\/linux\/bpf.h><\/span>
<\/span><\/span><\/span>#include<\/span> "bpf_helpers.h"<\/span>
<\/span><\/span><\/span><\/span>
<\/span><\/span>\/\/ 定义需要阻断的命令
<\/span><\/span><\/span><\/span>static<\/span> const<\/span> char<\/span> *<\/span>blocked_commands[] =<\/span> {
<\/span><\/span>    "rm"<\/span>,
<\/span><\/span>    "killall"<\/span>,
<\/span><\/span>    \/\/ 可以添加更多危险命令
<\/span><\/span><\/span><\/span>    NULL
<\/span><\/span>};
<\/span><\/span>
<\/span><\/span>SEC("kprobe\/sys_execve"<\/span>)
<\/span><\/span>int<\/span> kprobe__sys_execve(struct<\/span> pt_regs *<\/span>ctx)
<\/span><\/span>{
<\/span><\/span>    char<\/span> comm[16<\/span>];
<\/span><\/span>    bpf_get_current_comm(&<\/span>comm, sizeof<\/span>(comm));
<\/span><\/span>    
<\/span><\/span>    \/\/ 检查当前执行的命令是否在阻断列表中
<\/span><\/span><\/span><\/span>    for<\/span> (int<\/span> i =<\/span> 0<\/span>; blocked_commands[i] !=<\/span> NULL; i++<\/span>) {
<\/span><\/span>        if<\/span> (__builtin_memcmp(comm, blocked_commands[i], strlen(blocked_commands[i])) ==<\/span> 0<\/span>) {
<\/span><\/span>            \/\/ 匹配到危险命令，返回错误码阻断执行
<\/span><\/span><\/span><\/span>            return<\/span> -<\/span>EPERM;
<\/span><\/span>        }
<\/span><\/span>    }
<\/span><\/span>    
<\/span><\/span>    return<\/span> 0<\/span>;
<\/span><\/span>}
<\/span><\/span>
<\/span><\/span>char<\/span> _license[] SEC("license"<\/span>) =<\/span> "GPL"<\/span>;
<\/span><\/span><\/code><\/pre>编译eBPF程序<\/h4>
clang -O2 -target bpf -c block_execve.c -o block_execve.o
<\/span><\/span><\/code><\/pre>用户态代码<\/h4>
\/\/ user_program.c
<\/span><\/span><\/span><\/span>#include<\/span> <stdio.h><\/span>
<\/span><\/span><\/span>#include<\/span> <stdlib.h><\/span>
<\/span><\/span><\/span>#include<\/span> <string.h><\/span>
<\/span><\/span><\/span>#include<\/span> <unistd.h><\/span>
<\/span><\/span><\/span>#include<\/span> <sys\/resource.h><\/span>
<\/span><\/span><\/span>#include<\/span> <bpf\/libbpf.h><\/span>
<\/span><\/span><\/span>#include<\/span> "block_execve.skel.h"<\/span>
<\/span><\/span><\/span><\/span>
<\/span><\/span>int<\/span> main<\/span>(int<\/span> argc, char<\/span> **<\/span>argv)
<\/span><\/span>{
<\/span><\/span>    struct<\/span> block_execve_bpf *<\/span>obj;
<\/span><\/span>    int<\/span> err;
<\/span><\/span>    
<\/span><\/span>    \/\/ 加载eBPF程序
<\/span><\/span><\/span><\/span>    obj =<\/span> block_execve_bpf__open();
<\/span><\/span>    if<\/span> (!<\/span>obj) {
<\/span><\/span>        fprintf(stderr, "Failed to open BPF object<\/span>\n<\/span>"<\/span>);
<\/span><\/span>        return<\/span> 1<\/span>;
<\/span><\/span>    }
<\/span><\/span>    
<\/span><\/span>    \/\/ 加载并验证BPF程序
<\/span><\/span><\/span><\/span>    err =<\/span> block_execve_bpf__load(obj);
<\/span><\/span>    if<\/span> (err) {
<\/span><\/span>        fprintf(stderr, "Failed to load BPF object: %d<\/span>\n<\/span>"<\/span>, err);
<\/span><\/span>        goto<\/span> cleanup;
<\/span><\/span>    }
<\/span><\/span>    
<\/span><\/span>    \/\/ 附加kprobe
<\/span><\/span><\/span><\/span>    err =<\/span> block_execve_bpf__attach(obj);
<\/span><\/span>    if<\/span> (err) {
<\/span><\/span>        fprintf(stderr, "Failed to attach BPF programs: %d<\/span>\n<\/span>"<\/span>, err);
<\/span><\/span>        goto<\/span> cleanup;
<\/span><\/span>    }
<\/span><\/span>    
<\/span><\/span>    printf("eBPF program loaded and attached. Press Ctrl+C to exit.<\/span>\n<\/span>"<\/span>);
<\/span><\/span>    
<\/span><\/span>    \/\/ 保持程序运行
<\/span><\/span><\/span><\/span>    while<\/span> (1<\/span>) {
<\/span><\/span>        sleep(1<\/span>);
<\/span><\/span>    }
<\/span><\/span>    
<\/span><\/span>cleanup:
<\/span><\/span>    block_execve_bpf__destroy(obj);
<\/span><\/span>    return<\/span> err !=<\/span> 0<\/span>;
<\/span><\/span>}
<\/span><\/span><\/code><\/pre>查询监控日志<\/h4>
# 查看内核日志中记录的阻断事件<\/span>
<\/span><\/span>sudo cat \/var\/log\/kern.log | grep "Command blocked"<\/span>
<\/span><\/span><\/code><\/pre>停止eBPF程序<\/h4>
# 查找并杀死用户态程序<\/span>
<\/span><\/span>ps aux | grep user_program
<\/span><\/span>kill <pid>
<\/span><\/span>
<\/span><\/span># 卸载eBPF程序<\/span>
<\/span><\/span>sudo rm \/sys\/fs\/bpf\/block_execve
<\/span><\/span><\/code><\/pre>高级功能扩展<\/h2>


动态规则更新<\/strong>：<\/p>

实现用户态和内核态的通信机制<\/li>
允许运行时更新阻断命令列表<\/li>
<\/ul>
<\/li>

上下文感知阻断<\/strong>：<\/p>

结合进程树分析<\/li>
区分不同用户和环境的执行权限<\/li>
<\/ul>
<\/li>

审计日志增强<\/strong>：<\/p>

记录完整的命令参数<\/li>
关联用户信息和时间戳<\/li>
<\/ul>
<\/li>

性能优化<\/strong>：<\/p>

使用eBPF map优化命令匹配<\/li>
实现高效的哈希查找<\/li>
<\/ul>
<\/li>
<\/ol>
注意事项<\/h2>


内核兼容性<\/strong>：<\/p>

不同Linux内核版本可能需要调整eBPF代码<\/li>
测试目标系统内核的eBPF特性支持情况<\/li>
<\/ul>
<\/li>

安全考虑<\/strong>：<\/p>

保护eBPF程序不被恶意卸载<\/li>
防止权限绕过攻击<\/li>
<\/ul>
<\/li>

误报处理<\/strong>：<\/p>

设计白名单机制<\/li>
实现精细化的命令参数过滤<\/li>
<\/ul>
<\/li>
<\/ol>
总结<\/h2>
通过eBPF技术实现Linux下的高危命令阻断功能，能够在不影响系统性能的前提下提供有效的安全防护。该方案具有以下优势：<\/p>

内核级监控，难以被绕过<\/li>
低性能开销<\/li>
灵活的规则配置<\/li>
丰富的审计信息<\/li>
<\/ul>
随着eBPF技术的不断发展，EDR产品的检测和响应能力将得到进一步提升。<\/p>

Linux下EDR产品设计：高危命令阻断<\/h1>

概述<\/h2> 本文档详细介绍了在Linux环境下设计EDR(终端检测与响应)产品中高危命令阻断功能的实现方法。该功能主要通过eBPF技术监控和阻断危险系统命令的执行，如rm<\/code>和killall<\/code>等可能对系统造成破坏的操作。<\/p>

2. 核心组件<\/h3>

4. 具体实现步骤<\/h3>

概述<\/h2>
本文档详细介绍了在Linux环境下设计EDR(终端检测与响应)产品中高危命令阻断功能的实现方法。该功能主要通过eBPF技术监控和阻断危险系统命令的执行，如`rm<\/code>和killall<\/code>等可能对系统造成破坏的操作。<\/p>`