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19 KiB
19 KiB
6.1.22 pwn HITCONCTF2016 Sleepy_Holder
题目复现
$ file SleepyHolder
SleepyHolder: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 2.6.24, BuildID[sha1]=46f0e70abd9460828444d7f0975a8b2f2ddbad46, stripped
$ checksec -f SleepyHolder
RELRO STACK CANARY NX PIE RPATH RUNPATH FORTIFY Fortified Fortifiable FILE
Partial RELRO Canary found NX enabled No PIE No RPATH No RUNPATH Yes 0 2 SleepyHolder
$ strings libc.so.6 | grep "GNU C"
GNU C Library (Ubuntu GLIBC 2.23-0ubuntu3) stable release version 2.23, by Roland McGrath et al.
Compiled by GNU CC version 5.3.1 20160413.
64 位程序，开启了 Canary 和 NX，默认开启 ASLR。
在 Ubuntu-16.04 上玩一下：
$ ./SleepyHolder
Waking Sleepy Holder up ...
Hey! Do you have any secret?
I can help you to hold your secrets, and no one will be able to see it :)
1. Keep secret
2. Wipe secret
3. Renew secret
1
What secret do you want to keep?
1. Small secret
2. Big secret
3. Keep a huge secret and lock it forever
1
Tell me your secret:
AAAA
1. Keep secret
2. Wipe secret
3. Renew secret
1
What secret do you want to keep?
1. Small secret
2. Big secret
3. Keep a huge secret and lock it forever
3
Tell me your secret:
CCCC
1. Keep secret
2. Wipe secret
3. Renew secret
3
Which Secret do you want to renew?
1. Small secret
2. Big secret
1
Tell me your secret:
BBBB
1. Keep secret
2. Wipe secret
3. Renew secret
2
Which Secret do you want to wipe?
1. Small secret
2. Big secret
1
这一题看起来和上一题 Secret_Holder 差不多。同样是 small、big、huge 三种 secret，不同的是这里的 huge secret 是不可修改和删除的。另外在程序开始时会 sleep 几秒钟，不知道对利用有没有帮助。
题目解析
下面我们逐个来逆向这些功能。
Keep secret
[0x00400850]> pdf @ sub.What_secret_do_you_want_to_keep_93d
/ (fcn) sub.What_secret_do_you_want_to_keep_93d 452
| sub.What_secret_do_you_want_to_keep_93d ();
| ; var int local_14h @ rbp-0x14
| ; var int local_10h @ rbp-0x10
| ; var int local_8h @ rbp-0x8
| ; CALL XREF from 0x00400e3c (main)
| 0x0040093d push rbp
| 0x0040093e mov rbp, rsp
| 0x00400941 sub rsp, 0x20
| 0x00400945 mov rax, qword fs:[0x28] ; [0x28:8]=-1 ; '(' ; 40
| 0x0040094e mov qword [local_8h], rax
| 0x00400952 xor eax, eax
| 0x00400954 mov edi, str.What_secret_do_you_want_to_keep ; 0x400ee8 ; "What secret do you want to keep?"
| 0x00400959 call sym.imp.puts ; int puts(const char *s)
| 0x0040095e mov edi, str.1._Small_secret ; 0x400f09 ; "1. Small secret"
| 0x00400963 call sym.imp.puts ; int puts(const char *s)
| 0x00400968 mov edi, str.2._Big_secret ; 0x400f19 ; "2. Big secret"
| 0x0040096d call sym.imp.puts ; int puts(const char *s)
| 0x00400972 mov eax, dword [0x006020dc] ; [0x6020dc:4]=0
| 0x00400978 test eax, eax
| ,=< 0x0040097a jne 0x400986
| | 0x0040097c mov edi, str.3._Keep_a_huge_secret_and_lock_it_forever ; 0x400f28 ; "3. Keep a huge secret and lock it forever"
| | 0x00400981 call sym.imp.puts ; int puts(const char *s)
| | ; JMP XREF from 0x0040097a (sub.What_secret_do_you_want_to_keep_93d)
| `-> 0x00400986 lea rax, [local_10h]
| 0x0040098a mov edx, 4
| 0x0040098f mov esi, 0
| 0x00400994 mov rdi, rax
| 0x00400997 call sym.imp.memset ; void *memset(void *s, int c, size_t n)
| 0x0040099c lea rax, [local_10h]
| 0x004009a0 mov edx, 4
| 0x004009a5 mov rsi, rax
| 0x004009a8 mov edi, 0
| 0x004009ad mov eax, 0
| 0x004009b2 call sym.imp.read ; ssize_t read(int fildes, void *buf, size_t nbyte)
| 0x004009b7 lea rax, [local_10h]
| 0x004009bb mov rdi, rax
| 0x004009be call sym.imp.atoi ; int atoi(const char *str)
| 0x004009c3 mov dword [local_14h], eax
| 0x004009c6 mov eax, dword [local_14h]
| 0x004009c9 cmp eax, 2 ; 2
| ,=< 0x004009cc je 0x400a3d
| | 0x004009ce cmp eax, 3 ; 3
| ,==< 0x004009d1 je 0x400a96
| || 0x004009d7 cmp eax, 1 ; 1
| ,===< 0x004009da je 0x4009e1
| ,====< 0x004009dc jmp 0x400aeb
| |||| ; JMP XREF from 0x004009da (sub.What_secret_do_you_want_to_keep_93d)
| |`---> 0x004009e1 mov eax, dword [0x006020e0] ; [0x6020e0:4]=0
| | || 0x004009e7 test eax, eax
| |,===< 0x004009e9 je 0x4009f0
| ,=====< 0x004009eb jmp 0x400aeb
| ||||| ; JMP XREF from 0x004009e9 (sub.What_secret_do_you_want_to_keep_93d)
| ||`---> 0x004009f0 mov esi, 0x28 ; '(' ; 40
| || || 0x004009f5 mov edi, 1
| || || 0x004009fa call sym.imp.calloc ; void *calloc(size_t nmeb, size_t size)
| || || 0x004009ff mov qword [0x006020d0], rax ; [0x6020d0:8]=0
| || || 0x00400a06 mov dword [0x006020e0], 1 ; [0x6020e0:4]=0
| || || 0x00400a10 mov edi, str.Tell_me_your_secret: ; 0x400f52 ; "Tell me your secret: "
| || || 0x00400a15 call sym.imp.puts ; int puts(const char *s)
| || || 0x00400a1a mov rax, qword [0x006020d0] ; [0x6020d0:8]=0
| || || 0x00400a21 mov edx, 0x28 ; '(' ; 40
| || || 0x00400a26 mov rsi, rax
| || || 0x00400a29 mov edi, 0
| || || 0x00400a2e mov eax, 0
| || || 0x00400a33 call sym.imp.read ; ssize_t read(int fildes, void *buf, size_t nbyte)
| ||,===< 0x00400a38 jmp 0x400aeb
| ||||| ; JMP XREF from 0x004009cc (sub.What_secret_do_you_want_to_keep_93d)
| ||||`-> 0x00400a3d mov eax, dword [0x006020d8] ; [0x6020d8:4]=0
| |||| 0x00400a43 test eax, eax
| ||||,=< 0x00400a45 je 0x400a4c
| ,======< 0x00400a47 jmp 0x400aeb
| |||||| ; JMP XREF from 0x00400a45 (sub.What_secret_do_you_want_to_keep_93d)
| |||||`-> 0x00400a4c mov esi, 0xfa0 ; 4000
| ||||| 0x00400a51 mov edi, 1
| ||||| 0x00400a56 call sym.imp.calloc ; void *calloc(size_t nmeb, size_t size)
| ||||| 0x00400a5b mov qword [0x006020c0], rax ; [0x6020c0:8]=0
| ||||| 0x00400a62 mov dword [0x006020d8], 1 ; [0x6020d8:4]=0
| ||||| 0x00400a6c mov edi, str.Tell_me_your_secret: ; 0x400f52 ; "Tell me your secret: "
| ||||| 0x00400a71 call sym.imp.puts ; int puts(const char *s)
| ||||| 0x00400a76 mov rax, qword [0x006020c0] ; [0x6020c0:8]=0
| ||||| 0x00400a7d mov edx, 0xfa0 ; 4000
| ||||| 0x00400a82 mov rsi, rax
| ||||| 0x00400a85 mov edi, 0
| ||||| 0x00400a8a mov eax, 0
| ||||| 0x00400a8f call sym.imp.read ; ssize_t read(int fildes, void *buf, size_t nbyte)
| |||||,=< 0x00400a94 jmp 0x400aeb
| |||||| ; JMP XREF from 0x004009d1 (sub.What_secret_do_you_want_to_keep_93d)
| ||||`--> 0x00400a96 mov eax, dword [0x006020dc] ; [0x6020dc:4]=0
| |||| | 0x00400a9c test eax, eax
| ||||,==< 0x00400a9e je 0x400aa2
| ,=======< 0x00400aa0 jmp 0x400aeb
| ||||||| ; JMP XREF from 0x00400a9e (sub.What_secret_do_you_want_to_keep_93d)
| |||||`--> 0x00400aa2 mov esi, 0x61a80
| ||||| | 0x00400aa7 mov edi, 1
| ||||| | 0x00400aac call sym.imp.calloc ; void *calloc(size_t nmeb, size_t size)
| ||||| | 0x00400ab1 mov qword [0x006020c8], rax ; [0x6020c8:8]=0
| ||||| | 0x00400ab8 mov dword [0x006020dc], 1 ; [0x6020dc:4]=0
| ||||| | 0x00400ac2 mov edi, str.Tell_me_your_secret: ; 0x400f52 ; "Tell me your secret: "
| ||||| | 0x00400ac7 call sym.imp.puts ; int puts(const char *s)
| ||||| | 0x00400acc mov rax, qword [0x006020c8] ; [0x6020c8:8]=0
| ||||| | 0x00400ad3 mov edx, 0x61a80
| ||||| | 0x00400ad8 mov rsi, rax
| ||||| | 0x00400adb mov edi, 0
| ||||| | 0x00400ae0 mov eax, 0
| ||||| | 0x00400ae5 call sym.imp.read ; ssize_t read(int fildes, void *buf, size_t nbyte)
| ||||| | 0x00400aea nop
| ||||| | ; XREFS: JMP 0x004009dc JMP 0x004009eb JMP 0x00400a38 JMP 0x00400a47 JMP 0x00400a94 JMP 0x00400aa0
| `````-`-> 0x00400aeb mov rax, qword [local_8h]
| 0x00400aef xor rax, qword fs:[0x28]
| ,=< 0x00400af8 je 0x400aff
| | 0x00400afa call sym.imp.__stack_chk_fail ; void __stack_chk_fail(void)
| | ; JMP XREF from 0x00400af8 (sub.What_secret_do_you_want_to_keep_93d)
| `-> 0x00400aff leave
\ 0x00400b00 ret
Wipe secret
[0x00400850]> pdf @ sub.Which_Secret_do_you_want_to_wipe_b01
/ (fcn) sub.Which_Secret_do_you_want_to_wipe_b01 207
| sub.Which_Secret_do_you_want_to_wipe_b01 ();
| ; var int local_14h @ rbp-0x14
| ; var int local_10h @ rbp-0x10
| ; var int local_8h @ rbp-0x8
| ; CALL XREF from 0x00400e48 (main)
| 0x00400b01 push rbp
| 0x00400b02 mov rbp, rsp
| 0x00400b05 sub rsp, 0x20
| 0x00400b09 mov rax, qword fs:[0x28] ; [0x28:8]=-1 ; '(' ; 40
| 0x00400b12 mov qword [local_8h], rax
| 0x00400b16 xor eax, eax
| 0x00400b18 mov edi, str.Which_Secret_do_you_want_to_wipe ; 0x400f68 ; "Which Secret do you want to wipe?"
| 0x00400b1d call sym.imp.puts ; int puts(const char *s)
| 0x00400b22 mov edi, str.1._Small_secret ; 0x400f09 ; "1. Small secret"
| 0x00400b27 call sym.imp.puts ; int puts(const char *s)
| 0x00400b2c mov edi, str.2._Big_secret ; 0x400f19 ; "2. Big secret"
| 0x00400b31 call sym.imp.puts ; int puts(const char *s)
| 0x00400b36 lea rax, [local_10h]
| 0x00400b3a mov edx, 4
| 0x00400b3f mov esi, 0
| 0x00400b44 mov rdi, rax
| 0x00400b47 call sym.imp.memset ; void *memset(void *s, int c, size_t n)
| 0x00400b4c lea rax, [local_10h]
| 0x00400b50 mov edx, 4
| 0x00400b55 mov rsi, rax
| 0x00400b58 mov edi, 0
| 0x00400b5d mov eax, 0
| 0x00400b62 call sym.imp.read ; ssize_t read(int fildes, void *buf, size_t nbyte)
| 0x00400b67 lea rax, [local_10h]
| 0x00400b6b mov rdi, rax
| 0x00400b6e call sym.imp.atoi ; int atoi(const char *str)
| 0x00400b73 mov dword [local_14h], eax
| 0x00400b76 mov eax, dword [local_14h]
| 0x00400b79 cmp eax, 1 ; 1
| ,=< 0x00400b7c je 0x400b85
| | 0x00400b7e cmp eax, 2 ; 2
| ,==< 0x00400b81 je 0x400ba0
| ,===< 0x00400b83 jmp 0x400bba
| ||| ; JMP XREF from 0x00400b7c (sub.Which_Secret_do_you_want_to_wipe_b01)
| ||`-> 0x00400b85 mov rax, qword [0x006020d0] ; [0x6020d0:8]=0
| || 0x00400b8c mov rdi, rax
| || 0x00400b8f call sym.imp.free ; void free(void *ptr)
| || 0x00400b94 mov dword [0x006020e0], 0 ; [0x6020e0:4]=0
| ||,=< 0x00400b9e jmp 0x400bba
| ||| ; JMP XREF from 0x00400b81 (sub.Which_Secret_do_you_want_to_wipe_b01)
| |`--> 0x00400ba0 mov rax, qword [0x006020c0] ; [0x6020c0:8]=0
| | | 0x00400ba7 mov rdi, rax
| | | 0x00400baa call sym.imp.free ; void free(void *ptr)
| | | 0x00400baf mov dword [0x006020d8], 0 ; [0x6020d8:4]=0
| | | 0x00400bb9 nop
| | | ; JMP XREF from 0x00400b83 (sub.Which_Secret_do_you_want_to_wipe_b01)
| | | ; JMP XREF from 0x00400b9e (sub.Which_Secret_do_you_want_to_wipe_b01)
| `-`-> 0x00400bba mov rax, qword [local_8h]
| 0x00400bbe xor rax, qword fs:[0x28]
| ,=< 0x00400bc7 je 0x400bce
| | 0x00400bc9 call sym.imp.__stack_chk_fail ; void __stack_chk_fail(void)
| | ; JMP XREF from 0x00400bc7 (sub.Which_Secret_do_you_want_to_wipe_b01)
| `-> 0x00400bce leave
\ 0x00400bcf ret
Renew secret
[0x00400850]> pdf @ sub.Which_Secret_do_you_want_to_renew_bd0
/ (fcn) sub.Which_Secret_do_you_want_to_renew_bd0 259
| sub.Which_Secret_do_you_want_to_renew_bd0 ();
| ; var int local_14h @ rbp-0x14
| ; var int local_10h @ rbp-0x10
| ; var int local_8h @ rbp-0x8
| ; CALL XREF from 0x00400e54 (main)
| 0x00400bd0 push rbp
| 0x00400bd1 mov rbp, rsp
| 0x00400bd4 sub rsp, 0x20
| 0x00400bd8 mov rax, qword fs:[0x28] ; [0x28:8]=-1 ; '(' ; 40
| 0x00400be1 mov qword [local_8h], rax
| 0x00400be5 xor eax, eax
| 0x00400be7 mov edi, str.Which_Secret_do_you_want_to_renew ; 0x400f90 ; "Which Secret do you want to renew?"
| 0x00400bec call sym.imp.puts ; int puts(const char *s)
| 0x00400bf1 mov edi, str.1._Small_secret ; 0x400f09 ; "1. Small secret"
| 0x00400bf6 call sym.imp.puts ; int puts(const char *s)
| 0x00400bfb mov edi, str.2._Big_secret ; 0x400f19 ; "2. Big secret"
| 0x00400c00 call sym.imp.puts ; int puts(const char *s)
| 0x00400c05 lea rax, [local_10h]
| 0x00400c09 mov edx, 4
| 0x00400c0e mov esi, 0
| 0x00400c13 mov rdi, rax
| 0x00400c16 call sym.imp.memset ; void *memset(void *s, int c, size_t n)
| 0x00400c1b lea rax, [local_10h]
| 0x00400c1f mov edx, 4
| 0x00400c24 mov rsi, rax
| 0x00400c27 mov edi, 0
| 0x00400c2c mov eax, 0
| 0x00400c31 call sym.imp.read ; ssize_t read(int fildes, void *buf, size_t nbyte)
| 0x00400c36 lea rax, [local_10h]
| 0x00400c3a mov rdi, rax
| 0x00400c3d call sym.imp.atoi ; int atoi(const char *str)
| 0x00400c42 mov dword [local_14h], eax
| 0x00400c45 mov eax, dword [local_14h]
| 0x00400c48 cmp eax, 1 ; 1
| ,=< 0x00400c4b je 0x400c54
| | 0x00400c4d cmp eax, 2 ; 2
| ,==< 0x00400c50 je 0x400c8a
| ,===< 0x00400c52 jmp 0x400cbd
| ||| ; JMP XREF from 0x00400c4b (sub.Which_Secret_do_you_want_to_renew_bd0)
| ||`-> 0x00400c54 mov eax, dword [0x006020e0] ; [0x6020e0:4]=0
| || 0x00400c5a test eax, eax
| ||,=< 0x00400c5c je 0x400c88
| ||| 0x00400c5e mov edi, str.Tell_me_your_secret: ; 0x400f52 ; "Tell me your secret: "
| ||| 0x00400c63 call sym.imp.puts ; int puts(const char *s)
| ||| 0x00400c68 mov rax, qword [0x006020d0] ; [0x6020d0:8]=0
| ||| 0x00400c6f mov edx, 0x28 ; '(' ; 40
| ||| 0x00400c74 mov rsi, rax
| ||| 0x00400c77 mov edi, 0
| ||| 0x00400c7c mov eax, 0
| ||| 0x00400c81 call sym.imp.read ; ssize_t read(int fildes, void *buf, size_t nbyte)
| ,====< 0x00400c86 jmp 0x400cbd
| |||| ; JMP XREF from 0x00400c5c (sub.Which_Secret_do_you_want_to_renew_bd0)
| ,===`-> 0x00400c88 jmp 0x400cbd
| |||| ; JMP XREF from 0x00400c50 (sub.Which_Secret_do_you_want_to_renew_bd0)
| |||`--> 0x00400c8a mov eax, dword [0x006020d8] ; [0x6020d8:4]=0
| ||| 0x00400c90 test eax, eax
| ||| ,=< 0x00400c92 je 0x400cbc
| ||| | 0x00400c94 mov edi, str.Tell_me_your_secret: ; 0x400f52 ; "Tell me your secret: "
| ||| | 0x00400c99 call sym.imp.puts ; int puts(const char *s)
| ||| | 0x00400c9e mov rax, qword [0x006020c0] ; [0x6020c0:8]=0
| ||| | 0x00400ca5 mov edx, 0xfa0 ; 4000
| ||| | 0x00400caa mov rsi, rax
| ||| | 0x00400cad mov edi, 0
| ||| | 0x00400cb2 mov eax, 0
| ||| | 0x00400cb7 call sym.imp.read ; ssize_t read(int fildes, void *buf, size_t nbyte)
| ||| | ; JMP XREF from 0x00400c92 (sub.Which_Secret_do_you_want_to_renew_bd0)
| ||| `-> 0x00400cbc nop
| ||| ; JMP XREF from 0x00400c52 (sub.Which_Secret_do_you_want_to_renew_bd0)
| ||| ; JMP XREF from 0x00400c86 (sub.Which_Secret_do_you_want_to_renew_bd0)
| ||| ; JMP XREF from 0x00400c88 (sub.Which_Secret_do_you_want_to_renew_bd0)
| ```---> 0x00400cbd mov rax, qword [local_8h]
| 0x00400cc1 xor rax, qword fs:[0x28]
| ,=< 0x00400cca je 0x400cd1
| | 0x00400ccc call sym.imp.__stack_chk_fail ; void __stack_chk_fail(void)
| | ; JMP XREF from 0x00400cca (sub.Which_Secret_do_you_want_to_renew_bd0)
| `-> 0x00400cd1 leave
\ 0x00400cd2 ret