Microsoft Edge Chakra JIT - Bound Check Elimination Bug Exploit

Exploit for windows platform in category dos / poc / Chakra uses the InvariantBlockBackwardIterator class to backpropagate the information about the hoisted bound checks. But the class follows the linked list instaed of the control flow. This may lead to incorrectly remove the bound checks. In th...

Microsoft Edge Chakra JIT - Stack-to-Heap Copy (Incomplete Fix) (1)

Microsoft Edge Chakra JIT - Stack-to-Heap Copy Incomplete Fix 1 / Here's a snippet of JavascriptArray::BoxStackInstance. To fix issue 1420 , "deepCopy" was introduced. But it only deep-copies the array when "instance-head" is on the stack. So simply by adding a single line of code that allocates...

Microsoft Edge Chakra JIT - Stack-to-Heap Copy (Incomplete Fix) Exploit

Exploit for windows platform in category dos / poc / Here's a snippet of JavascriptArray::BoxStackInstance. To fix issue 1420 , "deepCopy" was introduced. But it only deep-copies the array when "instance-head" is on the stack. So simply by adding a single line of code that allocates "head" to the...

Microsoft Edge Chakra JIT - Stack-to-Heap Copy (Incomplete Fix) (2)

/ Here's a snippet of JavascriptArray::BoxStackInstance. template T JavascriptArray::BoxStackInstanceT instance, bool deepCopy AssertThreadContext::IsOnStackinstance; // On the stack, the we reserved a pointer before the object as to store the boxed value T boxedInstanceRef = T instance - 1; T...

Microsoft Edge Chakra JIT CallRegExSymbolFunction Return Check Fail Exploit

Exploit for windows platform in category dos / poc Microsoft Edge: Chakra: JIT: CallRegExSymbolFunction doesn't check the return type The "CallRegExSymbolFunction" method is used to call symbol functions in regexp objects. But it doesn't check the return value's type. Since the user can define th...

Microsoft Edge Chakra JIT - ImplicitCallFlags Checks Bypass

Microsoft Edge Chakra JIT - ImplicitCallFlags Checks Bypass / Here's a snippet of ExecuteImplicitCall which is responsible for updating the ImplicitCallFlags flag. template inline Js::Var ExecuteImplicitCallJs::RecyclableObject function, Js::ImplicitCallFlags flags, Fn implicitCall...

Microsoft Edge Chakra JIT - NewScObjectNoCtor Array Type Confusion Exploit

Exploit for windows platform in category dos / poc / This is similar to the previous issues 1457, 1459 MSRC 42551, MSRC 42552. If a JavaScript function is used as a consturctor, it sets the new object's "proto" to its "prototype". The JIT compiler uses NewScObjectNoCtor instructions to perform it...

Microsoft Edge Chakra JIT - Array.prototype.reverse Array Type Confusion Exploit

Exploit for windows platform in category dos / poc / This is simillar to the previous issue 1457. But this time, we use Array.prototype.reverse. Array.prototype.reverse can be inlined and may invoke EnsureNonNativeArray to convert the prototype of "this" to a Var array. Call flow:...

Microsoft Edge Chakra JIT - GlobOpt::OptTagChecks Must Consider IsLoopPrePass Properly (2)

Microsoft Edge Chakra JIT - GlobOpt::OptTagChecks Must Consider IsLoopPrePass Properly 2 It seems this is the patch for the bug. https://github.com/Microsoft/ChakraCore/pull/4226/commits/874551dd00ff6f404e593c7e0162efb54b953f5a The following two cases will bypass the fix. 1: function opt let obj ...

Microsoft Edge Chakra JIT - 'GlobOpt::OptTagChecks' Must Consider IsLoopPrePass Properly (2)

It seems this is the patch for the bug. https://github.com/Microsoft/ChakraCore/pull/4226/commits/874551dd00ff6f404e593c7e0162efb54b953f5a The following two cases will bypass the fix. 1: function opt let obj = new Number2.3023e-320; for let i = 0; i 1; i++ obj.x = 1; obj = +obj; obj.x = 1; functi...

Microsoft Edge Chakra JIT - ImplicitCallFlags Checks Bypass

/ Here's a snippet of ExecuteImplicitCall which is responsible for updating the ImplicitCallFlags flag. template inline Js::Var ExecuteImplicitCallJs::RecyclableObject function, Js::ImplicitCallFlags flags, Fn implicitCall ... Js::ImplicitCallFlags saveImplicitCallFlags = this-GetImplicitCallFlag...

Microsoft Edge Chakra JIT - Array Type Confusion via InitProto Instructions

Microsoft Edge Chakra JIT - Array Type Confusion via InitProto Instructions / If a native array is used as a prototype, it is converted to a Var array by the Js::JavascriptNativeFloatArray::SetIsPrototype method. In the JIT compiler, it uses InitProto instructions to set object literals' prototyp...

Microsoft Edge Chakra JIT - NewScObjectNoCtor Array Type Confusion

Microsoft Edge Chakra JIT - NewScObjectNoCtor Array Type Confusion / This is similar to the previous issues 1457, 1459 MSRC 42551, MSRC 42552. If a JavaScript function is used as a consturctor, it sets the new object's "proto" to its "prototype". The JIT compiler uses NewScObjectNoCtor instructio...

Microsoft Edge Chakra JIT - ImplicitCallFlags Checks Bypass Exploit

Exploit for windows platform in category dos / poc / Here's a snippet of ExecuteImplicitCall which is responsible for updating the ImplicitCallFlags flag. template inline Js::Var ExecuteImplicitCallJs::RecyclableObject function, Js::ImplicitCallFlags flags, Fn implicitCall ... Js::ImplicitCallFla...

Microsoft Edge Chakra JIT - Array Type Confusion via InitProto Instructions Exploit

Exploit for windows platform in category dos / poc / If a native array is used as a prototype, it is converted to a Var array by the Js::JavascriptNativeFloatArray::SetIsPrototype method. In the JIT compiler, it uses InitProto instructions to set object literals' prototype. But when optimizing...

Microsoft Edge Chakra JIT - 'Array.prototype.reverse' Array Type Confusion

/ This is simillar to the previous issue 1457. But this time, we use Array.prototype.reverse. Array.prototype.reverse can be inlined and may invoke EnsureNonNativeArray to convert the prototype of "this" to a Var array. Call flow: JavascriptArray::EntryReverse - FillFromPrototypes -...

Microsoft Edge Chakra JIT - 'LdThis' Type Confusion

/ LdThis instructions' value type is assumed to be "Object". Since "this" can be other objects like an array, it has to be assumed to be "LikelyObject", otherwise, operations to "this" will not be checked properly. PoC: / function optarr arr0 = 1.1; this0 = ; arr0 = 2.3023e-320; function main let...

Microsoft Edge Chakra JIT - Array.prototype.reverse Array Type Confusion

Microsoft Edge Chakra JIT - Array.prototype.reverse Array Type Confusion / This is simillar to the previous issue 1457. But this time, we use Array.prototype.reverse. Array.prototype.reverse can be inlined and may invoke EnsureNonNativeArray to convert the prototype of "this" to a Var array. Call...

Microsoft Edge Chakra JIT - GlobOpt::OptTagChecks Must Consider IsLoopPrePass Properly (2)

Exploit for windows platform in category dos / poc It seems this is the patch for the bug. https://github.com/Microsoft/ChakraCore/pull/4226/commits/874551dd00ff6f404e593c7e0162efb54b953f5a The following two cases will bypass the fix. 1: function opt let obj = new Number2.3023e-320; for let i = 0...

Microsoft Edge Chakra JIT - LdThis Type Confusion Exploit

Exploit for windows platform in category dos / poc / LdThis instructions' value type is assumed to be "Object". Since "this" can be other objects like an array, it has to be assumed to be "LikelyObject", otherwise, operations to "this" will not be checked properly. PoC: / function optarr arr0 =...