Vulnerabilities > CVE-2020-9817 - Incorrect Default Permissions vulnerability in Apple mac OS X

047910
CVSS 7.8 - HIGH
Attack vector
LOCAL
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
HIGH
Integrity impact
HIGH
Availability impact
HIGH
local
low complexity
apple
CWE-276
nessus

Summary

A permissions issue existed. This issue was addressed with improved permission validation. This issue is fixed in macOS Catalina 10.15.5. A malicious application may be able to gain root privileges.

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Accessing Functionality Not Properly Constrained by ACLs
    In applications, particularly web applications, access to functionality is mitigated by the authorization framework, whose job it is to map ACLs to elements of the application's functionality; particularly URL's for web apps. In the case that the administrator failed to specify an ACL for a particular element, an attacker may be able to access it with impunity. An attacker with the ability to access functionality not properly constrained by ACLs can obtain sensitive information and possibly compromise the entire application. Such an attacker can access resources that must be available only to users at a higher privilege level, can access management sections of the application or can run queries for data that he is otherwise not supposed to.
  • Directory Indexing
    An adversary crafts a request to a target that results in the target listing/indexing the content of a directory as output. One common method of triggering directory contents as output is to construct a request containing a path that terminates in a directory name rather than a file name since many applications are configured to provide a list of the directory's contents when such a request is received. An adversary can use this to explore the directory tree on a target as well as learn the names of files. This can often end up revealing test files, backup files, temporary files, hidden files, configuration files, user accounts, script contents, as well as naming conventions, all of which can be used by an attacker to mount additional attacks.
  • Footprinting
    An attacker engages in probing and exploration activity to identify constituents and properties of the target. Footprinting is a general term to describe a variety of information gathering techniques, often used by attackers in preparation for some attack. It consists of using tools to learn as much as possible about the composition, configuration, and security mechanisms of the targeted application, system or network. Information that might be collected during a footprinting effort could include open ports, applications and their versions, network topology, and similar information. While footprinting is not intended to be damaging (although certain activities, such as network scans, can sometimes cause disruptions to vulnerable applications inadvertently) it may often pave the way for more damaging attacks.
  • Embedding Scripts within Scripts
    An attack of this type exploits a programs' vulnerabilities that are brought on by allowing remote hosts to execute scripts. The attacker leverages this capability to execute scripts to execute his/her own script by embedding it within other scripts that the target software is likely to execute. The attacker must have the ability to inject script into script that is likely to be executed. If this is done, then the attacker can potentially launch a variety of probes and attacks against the web server's local environment, in many cases the so-called DMZ, back end resources the web server can communicate with, and other hosts. With the proliferation of intermediaries, such as Web App Firewalls, network devices, and even printers having JVMs and Web servers, there are many locales where an attacker can inject malicious scripts. Since this attack pattern defines scripts within scripts, there are likely privileges to execute said attack on the host. Of course, these attacks are not solely limited to the server side, client side scripts like Ajax and client side JavaScript can contain malicious scripts as well. In general all that is required is for there to be sufficient privileges to execute a script, but not protected against writing.
  • Web Logs Tampering
    Web Logs Tampering attacks involve an attacker injecting, deleting or otherwise tampering with the contents of web logs typically for the purposes of masking other malicious behavior. Additionally, writing malicious data to log files may target jobs, filters, reports, and other agents that process the logs in an asynchronous attack pattern. This pattern of attack is similar to "Log Injection-Tampering-Forging" except that in this case, the attack is targeting the logs of the web server and not the application.

Nessus

NASL familyMacOS X Local Security Checks
NASL idMACOS_HT211170.NASL
descriptionThe remote host is running a version of macOS / Mac OS X that is 10.15.x prior to 10.15.5, 10.13.x prior to 10.13.6 Security Update 2020-003, 10.14.x prior to 10.14.6 Security Update 2020-003. It is, therefore, affected by multiple vulnerabilities: - In ksh version 20120801, a flaw was found in the way it evaluates certain environment variables. An attacker could use this flaw to override or bypass environment restrictions to execute shell commands. Services and applications that allow remote unauthenticated attackers to provide one of those environment variables could allow them to exploit this issue remotely. (CVE-2019-14868) - In Zsh before 5.8, attackers able to execute commands can regain privileges dropped by the --no-PRIVILEGED option. Zsh fails to overwrite the saved uid, so the original privileges can be restored by executing MODULE_PATH=/dir/with/module zmodload with a module that calls setuid(). (CVE-2019-20044) - An out-of-bounds read was addressed with improved input validation. This issue is fixed in iOS 13.3.1 and iPadOS 13.3.1, macOS Catalina 10.15.3, tvOS 13.3.1, watchOS 6.1.2. Processing a maliciously crafted image may lead to arbitrary code execution. (CVE-2020-3878) Note that Nessus has not tested for this issue but has instead relied only on the operating system
last seen2020-06-12
modified2020-05-28
plugin id136930
published2020-05-28
reporterThis script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.
sourcehttps://www.tenable.com/plugins/nessus/136930
titlemacOS 10.15.x < 10.15.5 / 10.14.x < 10.14.6 Security Update 2020-003 / 10.13.x < 10.13.6 Security Update 2020-003
code
#
# (C) Tenable Network Security, Inc.
#

include('compat.inc');

if (description)
{
  script_id(136930);
  script_version("1.6");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/07/17");

  script_cve_id(
    "CVE-2019-14868",
    "CVE-2019-20044",
    "CVE-2020-3878",
    "CVE-2020-3882",
    "CVE-2020-9771",
    "CVE-2020-9772",
    "CVE-2020-9788",
    "CVE-2020-9789",
    "CVE-2020-9790",
    "CVE-2020-9791",
    "CVE-2020-9792",
    "CVE-2020-9793",
    "CVE-2020-9794",
    "CVE-2020-9795",
    "CVE-2020-9797",
    "CVE-2020-9804",
    "CVE-2020-9808",
    "CVE-2020-9809",
    "CVE-2020-9811",
    "CVE-2020-9812",
    "CVE-2020-9813",
    "CVE-2020-9814",
    "CVE-2020-9815",
    "CVE-2020-9816",
    "CVE-2020-9817",
    "CVE-2020-9821",
    "CVE-2020-9822",
    "CVE-2020-9824",
    "CVE-2020-9825",
    "CVE-2020-9826",
    "CVE-2020-9827",
    "CVE-2020-9828",
    "CVE-2020-9830",
    "CVE-2020-9831",
    "CVE-2020-9832",
    "CVE-2020-9833",
    "CVE-2020-9834",
    "CVE-2020-9837",
    "CVE-2020-9839",
    "CVE-2020-9841",
    "CVE-2020-9842",
    "CVE-2020-9844",
    "CVE-2020-9847",
    "CVE-2020-9851",
    "CVE-2020-9852",
    "CVE-2020-9855",
    "CVE-2020-9856",
    "CVE-2020-9857"
  );
  script_xref(name:"APPLE-SA", value:"HT211170");
  script_xref(name:"APPLE-SA", value:"APPLE-SA-2020-05-18");
  script_xref(name:"IAVA", value:"2020-A-0227-S");

  script_name(english:"macOS 10.15.x < 10.15.5 / 10.14.x < 10.14.6 Security Update 2020-003 / 10.13.x < 10.13.6 Security Update 2020-003");

  script_set_attribute(attribute:"synopsis", value:
"The remote host is missing a macOS update that fixes multiple vulnerabilities");
  script_set_attribute(attribute:"description", value:
"The remote host is running a version of macOS / Mac OS X that is 10.15.x prior to 10.15.5, 10.13.x prior to 10.13.6
Security Update 2020-003, 10.14.x prior to 10.14.6 Security Update 2020-003. It is, therefore, affected by multiple
vulnerabilities:

  - In ksh version 20120801, a flaw was found in the way it
    evaluates certain environment variables. An attacker
    could use this flaw to override or bypass environment
    restrictions to execute shell commands. Services and
    applications that allow remote unauthenticated attackers
    to provide one of those environment variables could
    allow them to exploit this issue remotely.
    (CVE-2019-14868)

  - In Zsh before 5.8, attackers able to execute commands
    can regain privileges dropped by the --no-PRIVILEGED
    option. Zsh fails to overwrite the saved uid, so the
    original privileges can be restored by executing
    MODULE_PATH=/dir/with/module zmodload with a module that
    calls setuid(). (CVE-2019-20044)

  - An out-of-bounds read was addressed with improved input
    validation. This issue is fixed in iOS 13.3.1 and iPadOS
    13.3.1, macOS Catalina 10.15.3, tvOS 13.3.1, watchOS
    6.1.2. Processing a maliciously crafted image may lead
    to arbitrary code execution. (CVE-2020-3878)

Note that Nessus has not tested for this issue but has instead relied only on the operating system's self-reported
version number.");
  script_set_attribute(attribute:"see_also", value:"https://support.apple.com/en-us/HT211170");
  script_set_attribute(attribute:"solution", value:
"Upgrade to macOS 10.15.5 / 10.14.x < 10.14.6 Security Update 2020-003 / 10.13.x < 10.13.6 Security Update 2020-003 or
later");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2020-9852");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2020/02/24");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/05/18");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/05/28");

  script_set_attribute(attribute:"plugin_type", value:"combined");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:apple:mac_os_x");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:apple:macos");
  script_set_attribute(attribute:"stig_severity", value:"I");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"MacOS X Local Security Checks");

  script_copyright(english:"This script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info.nasl", "os_fingerprint.nasl");
  script_require_ports("Host/MacOSX/Version", "Host/OS");

  exit(0);
}

include('vcf.inc');
include('lists.inc');
include('vcf_extras_apple.inc'); 

app_info = vcf::apple::macos::get_app_info();

constraints = [
  { 'max_version' : '10.15.4', 'min_version' : '10.15', 'fixed_build' : '19F96', 'fixed_display' : 'macOS Catalina 10.15.5' },
  { 'max_version' : '10.13.6', 'min_version' : '10.13', 'fixed_build' : '17G13033', 'fixed_display' : '10.13.6 Security Update 2020-003' },
  { 'max_version' : '10.14.6', 'min_version' : '10.14', 'fixed_build' : '18G5033', 'fixed_display' : '10.14.6 Security Update 2020-003' }
];

vcf::apple::macos::check_version_and_report(app_info:app_info, constraints:constraints, severity:SECURITY_HOLE);