7.5 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.7 High
AI Score
Confidence
Low
0.05 Low
EPSS
Percentile
92.9%
The remote Ubuntu 16.04 LTS / 18.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-6657-2 advisory.
An issue was discovered in Dnsmasq before 2.90. The default maximum EDNS.0 UDP packet size was set to 4096 but should be 1232 because of DNS Flag Day 2020. (CVE-2023-28450)
Certain DNSSEC aspects of the DNS protocol (in RFC 4033, 4034, 4035, 6840, and related RFCs) allow remote attackers to cause a denial of service (CPU consumption) via one or more DNSSEC responses, aka the KeyTrap issue. One of the concerns is that, when there is a zone with many DNSKEY and RRSIG records, the protocol specification implies that an algorithm must evaluate all combinations of DNSKEY and RRSIG records. (CVE-2023-50387)
The Closest Encloser Proof aspect of the DNS protocol (in RFC 5155 when RFC 9276 guidance is skipped) allows remote attackers to cause a denial of service (CPU consumption for SHA-1 computations) via DNSSEC responses in a random subdomain attack, aka the NSEC3 issue. The RFC 5155 specification implies that an algorithm must perform thousands of iterations of a hash function in certain situations. (CVE-2023-50868)
Note that Nessus has not tested for these issues but has instead relied only on the application’s self-reported version number.
#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-6657-2. The text
# itself is copyright (C) Canonical, Inc. See
# <https://ubuntu.com/security/notices>. Ubuntu(R) is a registered
# trademark of Canonical, Inc.
##
include('compat.inc');
if (description)
{
script_id(193872);
script_version("1.0");
script_set_attribute(attribute:"plugin_modification_date", value:"2024/04/25");
script_cve_id("CVE-2023-28450", "CVE-2023-50387", "CVE-2023-50868");
script_xref(name:"USN", value:"6657-2");
script_name(english:"Ubuntu 16.04 LTS / 18.04 LTS : Dnsmasq vulnerabilities (USN-6657-2)");
script_set_attribute(attribute:"synopsis", value:
"The remote Ubuntu host is missing one or more security updates.");
script_set_attribute(attribute:"description", value:
"The remote Ubuntu 16.04 LTS / 18.04 LTS host has packages installed that are affected by multiple vulnerabilities as
referenced in the USN-6657-2 advisory.
- An issue was discovered in Dnsmasq before 2.90. The default maximum EDNS.0 UDP packet size was set to 4096
but should be 1232 because of DNS Flag Day 2020. (CVE-2023-28450)
- Certain DNSSEC aspects of the DNS protocol (in RFC 4033, 4034, 4035, 6840, and related RFCs) allow remote
attackers to cause a denial of service (CPU consumption) via one or more DNSSEC responses, aka the
KeyTrap issue. One of the concerns is that, when there is a zone with many DNSKEY and RRSIG records, the
protocol specification implies that an algorithm must evaluate all combinations of DNSKEY and RRSIG
records. (CVE-2023-50387)
- The Closest Encloser Proof aspect of the DNS protocol (in RFC 5155 when RFC 9276 guidance is skipped)
allows remote attackers to cause a denial of service (CPU consumption for SHA-1 computations) via DNSSEC
responses in a random subdomain attack, aka the NSEC3 issue. The RFC 5155 specification implies that an
algorithm must perform thousands of iterations of a hash function in certain situations. (CVE-2023-50868)
Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version
number.");
script_set_attribute(attribute:"see_also", value:"https://ubuntu.com/security/notices/USN-6657-2");
script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C");
script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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-2023-50387");
script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
script_set_attribute(attribute:"exploit_available", value:"false");
script_set_attribute(attribute:"vuln_publication_date", value:"2023/03/15");
script_set_attribute(attribute:"patch_publication_date", value:"2024/04/24");
script_set_attribute(attribute:"plugin_publication_date", value:"2024/04/25");
script_set_attribute(attribute:"plugin_type", value:"local");
script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:16.04:-:lts");
script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:18.04:-:lts");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:dnsmasq");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:dnsmasq-base");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:dnsmasq-base-lua");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:dnsmasq-utils");
script_set_attribute(attribute:"generated_plugin", value:"current");
script_end_attributes();
script_category(ACT_GATHER_INFO);
script_family(english:"Ubuntu Local Security Checks");
script_copyright(english:"Ubuntu Security Notice (C) 2024 Canonical, Inc. / NASL script (C) 2024 and is owned by Tenable, Inc. or an Affiliate thereof.");
script_dependencies("ssh_get_info.nasl");
script_require_keys("Host/cpu", "Host/Ubuntu", "Host/Ubuntu/release", "Host/Debian/dpkg-l");
exit(0);
}
include('debian_package.inc');
if ( ! get_kb_item('Host/local_checks_enabled') ) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var os_release = get_kb_item('Host/Ubuntu/release');
if ( isnull(os_release) ) audit(AUDIT_OS_NOT, 'Ubuntu');
os_release = chomp(os_release);
if (! ('16.04' >< os_release || '18.04' >< os_release)) audit(AUDIT_OS_NOT, 'Ubuntu 16.04 / 18.04', 'Ubuntu ' + os_release);
if ( ! get_kb_item('Host/Debian/dpkg-l') ) audit(AUDIT_PACKAGE_LIST_MISSING);
var cpu = get_kb_item('Host/cpu');
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ('x86_64' >!< cpu && cpu !~ "^i[3-6]86$" && 's390' >!< cpu && 'aarch64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Ubuntu', cpu);
var pkgs = [
{'osver': '16.04', 'pkgname': 'dnsmasq', 'pkgver': '2.90-0ubuntu0.16.04.1+esm1'},
{'osver': '16.04', 'pkgname': 'dnsmasq-base', 'pkgver': '2.90-0ubuntu0.16.04.1+esm1'},
{'osver': '16.04', 'pkgname': 'dnsmasq-base-lua', 'pkgver': '2.90-0ubuntu0.16.04.1+esm1'},
{'osver': '16.04', 'pkgname': 'dnsmasq-utils', 'pkgver': '2.90-0ubuntu0.16.04.1+esm1'},
{'osver': '18.04', 'pkgname': 'dnsmasq', 'pkgver': '2.90-0ubuntu0.18.04.1+esm1'},
{'osver': '18.04', 'pkgname': 'dnsmasq-base', 'pkgver': '2.90-0ubuntu0.18.04.1+esm1'},
{'osver': '18.04', 'pkgname': 'dnsmasq-base-lua', 'pkgver': '2.90-0ubuntu0.18.04.1+esm1'},
{'osver': '18.04', 'pkgname': 'dnsmasq-utils', 'pkgver': '2.90-0ubuntu0.18.04.1+esm1'}
];
var flag = 0;
foreach package_array ( pkgs ) {
var osver = NULL;
var pkgname = NULL;
var pkgver = NULL;
if (!empty_or_null(package_array['osver'])) osver = package_array['osver'];
if (!empty_or_null(package_array['pkgname'])) pkgname = package_array['pkgname'];
if (!empty_or_null(package_array['pkgver'])) pkgver = package_array['pkgver'];
if (osver && pkgname && pkgver) {
if (ubuntu_check(osver:osver, pkgname:pkgname, pkgver:pkgver)) flag++;
}
}
if (flag)
{
security_report_v4(
port : 0,
severity : SECURITY_HOLE,
extra : ubuntu_report_get()
);
exit(0);
}
else
{
var tested = ubuntu_pkg_tests_get();
if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'dnsmasq / dnsmasq-base / dnsmasq-base-lua / dnsmasq-utils');
}
Vendor | Product | Version | CPE |
---|---|---|---|
canonical | ubuntu_linux | 16.04 | cpe:/o:canonical:ubuntu_linux:16.04:-:lts |
canonical | ubuntu_linux | 18.04 | cpe:/o:canonical:ubuntu_linux:18.04:-:lts |
canonical | ubuntu_linux | dnsmasq | p-cpe:/a:canonical:ubuntu_linux:dnsmasq |
canonical | ubuntu_linux | dnsmasq-base | p-cpe:/a:canonical:ubuntu_linux:dnsmasq-base |
canonical | ubuntu_linux | dnsmasq-utils | p-cpe:/a:canonical:ubuntu_linux:dnsmasq-utils |
canonical | ubuntu_linux | dnsmasq-base-lua | p-cpe:/a:canonical:ubuntu_linux:dnsmasq-base-lua |
7.5 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.7 High
AI Score
Confidence
Low
0.05 Low
EPSS
Percentile
92.9%