Vulnerabilities > CVE-2020-9792 - Improper Input Validation vulnerability in Apple mac OS X

047910
CVSS 4.6 - MEDIUM
Attack vector
PHYSICAL
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
NONE
Integrity impact
NONE
Availability impact
HIGH
low complexity
apple
CWE-20
nessus

Summary

A validation issue was addressed with improved input sanitization. This issue is fixed in iOS 13.5 and iPadOS 13.5, macOS Catalina 10.15.5. A USB device may be able to cause a denial of service.

Vulnerable Configurations

Part Description Count
OS
Apple
415

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Buffer Overflow via Environment Variables
    This attack pattern involves causing a buffer overflow through manipulation of environment variables. Once the attacker finds that they can modify an environment variable, they may try to overflow associated buffers. This attack leverages implicit trust often placed in environment variables.
  • Server Side Include (SSI) Injection
    An attacker can use Server Side Include (SSI) Injection to send code to a web application that then gets executed by the web server. Doing so enables the attacker to achieve similar results to Cross Site Scripting, viz., arbitrary code execution and information disclosure, albeit on a more limited scale, since the SSI directives are nowhere near as powerful as a full-fledged scripting language. Nonetheless, the attacker can conveniently gain access to sensitive files, such as password files, and execute shell commands.
  • Cross Zone Scripting
    An attacker is able to cause a victim to load content into their web-browser that bypasses security zone controls and gain access to increased privileges to execute scripting code or other web objects such as unsigned ActiveX controls or applets. This is a privilege elevation attack targeted at zone-based web-browser security. In a zone-based model, pages belong to one of a set of zones corresponding to the level of privilege assigned to that page. Pages in an untrusted zone would have a lesser level of access to the system and/or be restricted in the types of executable content it was allowed to invoke. In a cross-zone scripting attack, a page that should be assigned to a less privileged zone is granted the privileges of a more trusted zone. This can be accomplished by exploiting bugs in the browser, exploiting incorrect configuration in the zone controls, through a cross-site scripting attack that causes the attackers' content to be treated as coming from a more trusted page, or by leveraging some piece of system functionality that is accessible from both the trusted and less trusted zone. This attack differs from "Restful Privilege Escalation" in that the latter correlates to the inadequate securing of RESTful access methods (such as HTTP DELETE) on the server, while cross-zone scripting attacks the concept of security zones as implemented by a browser.
  • Cross Site Scripting through Log Files
    An attacker may leverage a system weakness where logs are susceptible to log injection to insert scripts into the system's logs. If these logs are later viewed by an administrator through a thin administrative interface and the log data is not properly HTML encoded before being written to the page, the attackers' scripts stored in the log will be executed in the administrative interface with potentially serious consequences. This attack pattern is really a combination of two other attack patterns: log injection and stored cross site scripting.
  • Command Line Execution through SQL Injection
    An attacker uses standard SQL injection methods to inject data into the command line for execution. This could be done directly through misuse of directives such as MSSQL_xp_cmdshell or indirectly through injection of data into the database that would be interpreted as shell commands. Sometime later, an unscrupulous backend application (or could be part of the functionality of the same application) fetches the injected data stored in the database and uses this data as command line arguments without performing proper validation. The malicious data escapes that data plane by spawning new commands to be executed on the host.

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);