Faiblesses connexes
CWE-ID |
Nom de la faiblesse |
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
Metric |
Score |
Sévérité |
CVSS Vecteur |
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 MetricsThe Exploitability metrics reflect the characteristics of the thing that is vulnerable, which we refer to formally as the vulnerable component. Attack VectorThis metric reflects the context by which vulnerability exploitation is possible. 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 ComplexityThis metric describes the conditions beyond the attacker's control that must exist in order to exploit the vulnerability. Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component. Privileges RequiredThis metric describes the level of privileges an attacker must possess before successfully exploiting the vulnerability. 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 InteractionThis metric captures the requirement for a user, other than the attacker, to participate in the successful compromise of the vulnerable component. The vulnerable system can be exploited without interaction from any user. Base: Scope MetricsAn 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. ScopeFormally, 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. 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 MetricsThe Impact metrics refer to the properties of the impacted component. Confidentiality ImpactThis metric measures the impact to the confidentiality of the information resources managed by a software component due to a successfully exploited vulnerability. 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 ImpactThis metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. 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 ImpactThis metric measures the impact to the availability of the impacted component resulting from a successfully exploited vulnerability. 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 MetricsThe 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 est un modèle de notation qui prédit la probabilité qu'une vulnérabilité soit exploitée.
EPSS Score
Le modèle EPSS produit un score de probabilité compris entre 0 et 1 (0 et 100 %). Plus la note est élevée, plus la probabilité qu'une vulnérabilité soit exploitée est grande.
EPSS Percentile
Le percentile est utilisé pour classer les CVE en fonction de leur score EPSS. Par exemple, une CVE dans le 95e percentile selon son score EPSS est plus susceptible d'être exploitée que 95 % des autres CVE. Ainsi, le percentile sert à comparer le score EPSS d'une CVE par rapport à d'autres CVE.
Informations sur l'Exploit
Exploit Database EDB-ID : 45436
Date de publication : 2018-09-18 22:00 +00:00
Auteur : Google Security Research
EDB Vérifié : 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 objects 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