CVE-2018-8410 : Detail

CVE-2018-8410

7.8
/
High
73.72%V3
Local
2018-09-12
22h00 +00:00
2018-09-21
07h57 +00:00
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CVE Descriptions

An elevation of privilege vulnerability exists when the Windows Kernel API improperly handles registry objects in memory, aka "Windows Registry Elevation of Privilege Vulnerability." This affects Windows 7, Windows Server 2012 R2, Windows RT 8.1, Windows Server 2012, Windows 8.1, Windows Server 2016, Windows Server 2008 R2, Windows 10, Windows 10 Servers.

CVE Informations

Related Weaknesses

CWE-ID Weakness Name Source
CWE-404 Improper Resource Shutdown or Release
The product does not release or incorrectly releases a resource before it is made available for re-use.

Metrics

Metrics Score Severity CVSS Vector Source
V3.0 7.8 HIGH CVSS:3.0/AV:L/AC:L/PR:L/UI:N/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.

Local

A vulnerability exploitable with Local access means that the vulnerable component is not bound to the network stack, and the attacker's path is via read/write/execute capabilities. In some cases, the attacker may be logged in locally in order to exploit the vulnerability, otherwise, she may rely on User Interaction to execute a malicious file.

Attack Complexity

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

Low

Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.

Privileges Required

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

Low

The attacker is authorized with (i.e. requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.

User Interaction

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

None

The vulnerable system can be exploited without interaction from any user.

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 7.2 AV:L/AC:L/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 : 45436

Publication date : 2018-09-18 22h00 +00:00
Author : Google Security Research
EDB Verified : Yes

Windows: Double Dereference in NtEnumerateKey Elevation of Privilege Platform: Windows 10 1803 (not vulnerable in earlier versions) Class: Elevation of Privilege Summary: A number of registry system calls do not correctly handle pre-defined keys resulting in a double dereference which can lead to EoP. Description: The registry contains a couple of predefined keys, to generate performance information. These actually exist in the the machine hive under \Registry\Machine\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Perflib. When these keys are opened the kernel returns a status code of STATUS_PREDEFINED_KEY, but it also returns a handle to the key. The kernel doesn’t allow these keys to be used for many operations such as enumeration of subkeys and values, so these system calls check before the key is used and returns STATUS_INVALID_HANDLE. The code for this in NtEnumerateKey looks like the following: status = ObReferenceObjectByHandle(Handle, KEY_ENUMERATE, CmKeyObjectType, &Object); if ( status >= 0 && Object->Type != 'ky02' ) { status = STATUS_INVALID_HANDLE; ObfDereferenceObject(Object); <-- Dereference object, } if (status < 0) { goto EXIT_LABEL; } This code in itself is fine, but in 1803 at the exit label we find the following additional code: if (Object) ObfDereferenceObject(Object); This results in the object being dereferenced twice. Due the way the object reference counting works this will not be noticed until the key handle is closed, which results in a REFERENCE_BY_POINTER bugcheck being generated. This might only be a local DoS if the issue was caught earlier, but because the caller can do other things with the corrupted object we can potentially turn this into a UaF and from there elevate privileges. For example the provided PoC passes the handle to NtDuplicateObject which results in the kernel modifying a free pool allocation. I’d recommend ensuring you check all similar functions such as NtEnumerateValueKey as there seems to be a common issue, perhaps it’s a macro or template which is generating the bad code. The following is an example dump from a crash, at the end the !pool command is used on the object address to demonstrate the memory allocation was freed before being modified. Use !analyze -v to get detailed debugging information. BugCheck 18, {0, ffff8e0db3a0f7a0, 2, ffffffffffffffff} Probably caused by : ntkrnlmp.exe ( nt!ObfDereferenceObjectWithTag+155dd9 ) Followup: MachineOwner --------- 0: kd> !analyze -v ******************************************************************************* * * * Bugcheck Analysis * * * ******************************************************************************* REFERENCE_BY_POINTER (18) Arguments: Arg1: 0000000000000000, Object type of the object whose reference count is being lowered Arg2: ffff8e0db3a0f7a0, Object whose reference count is being lowered Arg3: 0000000000000002, Reserved Arg4: ffffffffffffffff, Reserved The reference count of an object is illegal for the current state of the object. Each time a driver uses a pointer to an object the driver calls a kernel routine to increment the reference count of the object. When the driver is done with the pointer the driver calls another kernel routine to decrement the reference count. Drivers must match calls to the increment and decrement routines. This bugcheck can occur because an object's reference count goes to zero while there are still open handles to the object, in which case the fourth parameter indicates the number of opened handles. It may also occur when the object’s reference count drops below zero whether or not there are open handles to the object, and in that case the fourth parameter contains the actual value of the pointer references count. Debugging Details: ------------------ DUMP_CLASS: 1 DUMP_QUALIFIER: 401 BUILD_VERSION_STRING: 17134.1.amd64fre.rs4_release.180410-1804 SYSTEM_MANUFACTURER: Microsoft Corporation VIRTUAL_MACHINE: HyperV SYSTEM_PRODUCT_NAME: Virtual Machine SYSTEM_SKU: None SYSTEM_VERSION: Hyper-V UEFI Release v3.0 BIOS_VENDOR: Microsoft Corporation BIOS_VERSION: Hyper-V UEFI Release v3.0 BIOS_DATE: 03/02/2018 BASEBOARD_MANUFACTURER: Microsoft Corporation BASEBOARD_PRODUCT: Virtual Machine BASEBOARD_VERSION: Hyper-V UEFI Release v3.0 DUMP_TYPE: 1 BUGCHECK_P1: 0 BUGCHECK_P2: ffff8e0db3a0f7a0 BUGCHECK_P3: 2 BUGCHECK_P4: ffffffffffffffff CPU_COUNT: 2 CPU_MHZ: a98 CPU_VENDOR: GenuineIntel CPU_FAMILY: 6 CPU_MODEL: 8e CPU_STEPPING: 9 CPU_MICROCODE: 6,8e,9,0 (F,M,S,R) SIG: FFFFFFFF'00000000 (cache) FFFFFFFF'00000000 (init) DEFAULT_BUCKET_ID: WIN8_DRIVER_FAULT BUGCHECK_STR: 0x18 PROCESS_NAME: PoC_NtEnumerateKey_EoP.exe CURRENT_IRQL: 0 ANALYSIS_SESSION_HOST: DESKTOP-JA4I3EF ANALYSIS_SESSION_TIME: 06-19-2018 13:36:38.0158 ANALYSIS_VERSION: 10.0.15063.468 amd64fre LAST_CONTROL_TRANSFER: from fffff80357473ab9 to fffff8035742c330 STACK_TEXT: ffffb78e`5a91f678 fffff803`57473ab9 : 00000000`00000018 00000000`00000000 ffff8e0d`b3a0f7a0 00000000`00000002 : nt!KeBugCheckEx ffffb78e`5a91f680 fffff803`57751b9b : 00000000`00000000 00000000`00000000 00020019`00000000 ffffb78e`5a91f7c0 : nt!ObfDereferenceObjectWithTag+0x155dd9 ffffb78e`5a91f6c0 fffff803`5775157d : ffffe58b`763cf580 00000a50`00000040 ffffe58b`75c75f20 00000000`00000001 : nt!ObDuplicateObject+0x58b ffffb78e`5a91f980 fffff803`5743c943 : ffffe58b`763c4700 00000000`008fe098 ffffb78e`5a91fa28 00000000`00000000 : nt!NtDuplicateObject+0x12d ffffb78e`5a91fa10 00007ffa`f3cda634 : 00000000`00000000 00000000`00000000 00000000`00000000 00000000`00000000 : nt!KiSystemServiceCopyEnd+0x13 00000000`008fe078 00000000`00000000 : 00000000`00000000 00000000`00000000 00000000`00000000 00000000`00000000 : 0x00007ffa`f3cda634 STACK_COMMAND: kb THREAD_SHA1_HASH_MOD_FUNC: 4fc60443ee144421725d502d6e3b53056b889c26 THREAD_SHA1_HASH_MOD_FUNC_OFFSET: c219a3da6c3050112ed885b130b5ebbab9cdff96 THREAD_SHA1_HASH_MOD: f08ac56120cad14894587db086f77ce277bfae84 FOLLOWUP_IP: nt!ObfDereferenceObjectWithTag+155dd9 fffff803`57473ab9 cc int 3 FAULT_INSTR_CODE: 4e8d48cc SYMBOL_STACK_INDEX: 1 SYMBOL_NAME: nt!ObfDereferenceObjectWithTag+155dd9 FOLLOWUP_NAME: MachineOwner MODULE_NAME: nt IMAGE_NAME: ntkrnlmp.exe DEBUG_FLR_IMAGE_TIMESTAMP: 5b1a4590 BUCKET_ID_FUNC_OFFSET: 155dd9 FAILURE_BUCKET_ID: 0x18_OVER_DEREFERENCE_nt!ObfDereferenceObjectWithTag BUCKET_ID: 0x18_OVER_DEREFERENCE_nt!ObfDereferenceObjectWithTag PRIMARY_PROBLEM_CLASS: 0x18_OVER_DEREFERENCE_nt!ObfDereferenceObjectWithTag TARGET_TIME: 2018-06-19T20:33:20.000Z OSBUILD: 17134 OSSERVICEPACK: 0 SERVICEPACK_NUMBER: 0 OS_REVISION: 0 SUITE_MASK: 272 PRODUCT_TYPE: 1 OSPLATFORM_TYPE: x64 OSNAME: Windows 10 OSEDITION: Windows 10 WinNt TerminalServer SingleUserTS OS_LOCALE: USER_LCID: 0 OSBUILD_TIMESTAMP: 2018-06-08 02:00:00 BUILDDATESTAMP_STR: 180410-1804 BUILDLAB_STR: rs4_release BUILDOSVER_STR: 10.0.17134.1.amd64fre.rs4_release.180410-1804 ANALYSIS_SESSION_ELAPSED_TIME: 13a4 ANALYSIS_SOURCE: KM FAILURE_ID_HASH_STRING: km:0x18_over_dereference_nt!obfdereferenceobjectwithtag FAILURE_ID_HASH: {4139309c-4e9f-52f0-ac5e-4041e7a86a20} Followup: MachineOwner --------- 0: kd> !pool ffff8e0db3a0f7a0 Pool page ffff8e0db3a0f7a0 region is Paged pool ffff8e0db3a0f000 size: 150 previous size: 0 (Free ) FMfn ffff8e0db3a0f150 size: 130 previous size: 150 (Free) Free ffff8e0db3a0f280 size: 40 previous size: 130 (Allocated) MPan ffff8e0db3a0f2c0 size: 50 previous size: 40 (Free ) SeAt ffff8e0db3a0f310 size: c0 previous size: 50 (Free ) Se ffff8e0db3a0f3d0 size: 50 previous size: c0 (Free) Free ffff8e0db3a0f420 size: 220 previous size: 50 (Allocated) FMfn ffff8e0db3a0f640 size: a0 previous size: 220 (Allocated) Sect ffff8e0db3a0f6e0 size: 50 previous size: a0 (Free) Free *ffff8e0db3a0f730 size: 100 previous size: 50 (Free ) *Key Pooltag Key : Key objects ffff8e0db3a0f830 size: 10 previous size: 100 (Free) Free ffff8e0db3a0f840 size: e0 previous size: 10 (Allocated) NtFs ffff8e0db3a0f920 size: c0 previous size: e0 (Allocated) FIcs ffff8e0db3a0f9e0 size: c0 previous size: c0 (Free ) SeTd ffff8e0db3a0faa0 size: 560 previous size: c0 (Allocated) Ntff Proof of Concept: I’ve provided a PoC as a C# project. This only demonstrates the issue and proves that it would be possible to force this issue into a UaF even with the mitigations on reference counting. 1) Compile the C# project. It will need to grab the NtApiDotNet from NuGet to work. 2) Run the PoC on an machine with Windows 10 1803, I’ve only tested x64. 3) The OS should crash, inspect it in a kernel debugger or from the crash dump. Expected Result: The OS ignores the pre-defined key as expected. Observed Result: The object’s reference count is corrupted. Proof of Concept: https://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/45436.zip

Products Mentioned

Configuraton 0

Microsoft>>Windows_10 >> Version -

Microsoft>>Windows_10 >> Version 1607

Microsoft>>Windows_10 >> Version 1703

Microsoft>>Windows_10 >> Version 1709

Microsoft>>Windows_10 >> Version 1803

Microsoft>>Windows_7 >> Version -

Microsoft>>Windows_8.1 >> Version -

Microsoft>>Windows_rt_8.1 >> Version -

Microsoft>>Windows_server >> Version 2008

    Microsoft>>Windows_server >> Version 2008

      Microsoft>>Windows_server >> Version 2012

      Microsoft>>Windows_server >> Version 2012

      Microsoft>>Windows_server >> Version 2016

        Microsoft>>Windows_server >> Version 2016

          Microsoft>>Windows_server >> Version 2016

            References

            http://www.securitytracker.com/id/1041635
            Tags : vdb-entry, x_refsource_SECTRACK
            https://www.exploit-db.com/exploits/45436/
            Tags : exploit, x_refsource_EXPLOIT-DB
            http://www.securityfocus.com/bid/105256
            Tags : vdb-entry, x_refsource_BID