CVSS2
Attack Vector
NETWORK
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
PARTIAL
Availability Impact
PARTIAL
AV:N/AC:L/Au:N/C:P/I:P/A:P
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
Percentile
93.0%
The version of expat installed on the remote host is prior to 2.1.0-12.27. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS-2022-1573 advisory.
xmltok_impl.c in Expat (aka libexpat) before 2.4.5 lacks certain validation of encoding, such as checks for whether a UTF-8 character is valid in a certain context. (CVE-2022-25235)
xmlparse.c in Expat (aka libexpat) before 2.4.5 allows attackers to insert namespace-separator characters into namespace URIs. (CVE-2022-25236)
Note that Nessus has not tested for this issue but has instead relied only on the application’s self-reported version number.
#%NASL_MIN_LEVEL 70300
##
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux AMI Security Advisory ALAS-2022-1573.
##
include('deprecated_nasl_level.inc');
include('compat.inc');
if (description)
{
script_id(158790);
script_version("1.3");
script_set_attribute(attribute:"plugin_modification_date", value:"2022/05/25");
script_cve_id("CVE-2022-25235", "CVE-2022-25236");
script_xref(name:"ALAS", value:"2022-1573");
script_name(english:"Amazon Linux AMI : expat (ALAS-2022-1573)");
script_set_attribute(attribute:"synopsis", value:
"The remote Amazon Linux AMI host is missing a security update.");
script_set_attribute(attribute:"description", value:
"The version of expat installed on the remote host is prior to 2.1.0-12.27. It is, therefore, affected by multiple
vulnerabilities as referenced in the ALAS-2022-1573 advisory.
- xmltok_impl.c in Expat (aka libexpat) before 2.4.5 lacks certain validation of encoding, such as checks
for whether a UTF-8 character is valid in a certain context. (CVE-2022-25235)
- xmlparse.c in Expat (aka libexpat) before 2.4.5 allows attackers to insert namespace-separator characters
into namespace URIs. (CVE-2022-25236)
Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version
number.");
script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/ALAS-2022-1573.html");
script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2022-25235.html");
script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2022-25236.html");
script_set_attribute(attribute:"solution", value:
"Run 'yum update expat' to update your system.");
script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P");
script_set_cvss_temporal_vector("CVSS2#E:POC/RL:OF/RC:C");
script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H");
script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
script_set_attribute(attribute:"cvss_score_source", value:"CVE-2022-25236");
script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
script_set_attribute(attribute:"exploit_available", value:"true");
script_set_attribute(attribute:"vuln_publication_date", value:"2022/02/16");
script_set_attribute(attribute:"patch_publication_date", value:"2022/03/09");
script_set_attribute(attribute:"plugin_publication_date", value:"2022/03/10");
script_set_attribute(attribute:"plugin_type", value:"local");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:expat");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:expat-debuginfo");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:expat-devel");
script_set_attribute(attribute:"cpe", value:"cpe:/o:amazon:linux");
script_end_attributes();
script_category(ACT_GATHER_INFO);
script_family(english:"Amazon Linux Local Security Checks");
script_copyright(english:"This script is Copyright (C) 2022 and is owned by Tenable, Inc. or an Affiliate thereof.");
script_dependencies("ssh_get_info.nasl");
script_require_keys("Host/local_checks_enabled", "Host/AmazonLinux/release", "Host/AmazonLinux/rpm-list");
exit(0);
}
include("audit.inc");
include("global_settings.inc");
include("rpm.inc");
if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var release = get_kb_item("Host/AmazonLinux/release");
if (isnull(release) || !strlen(release)) audit(AUDIT_OS_NOT, "Amazon Linux");
var os_ver = pregmatch(pattern: "^AL(A|\d)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Amazon Linux");
var os_ver = os_ver[1];
if (os_ver != "A")
{
if (os_ver == 'A') os_ver = 'AMI';
audit(AUDIT_OS_NOT, "Amazon Linux AMI", "Amazon Linux " + os_ver);
}
if (!get_kb_item("Host/AmazonLinux/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);
var pkgs = [
{'reference':'expat-2.1.0-12.27.amzn1', 'cpu':'i686', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
{'reference':'expat-2.1.0-12.27.amzn1', 'cpu':'x86_64', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
{'reference':'expat-debuginfo-2.1.0-12.27.amzn1', 'cpu':'i686', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
{'reference':'expat-debuginfo-2.1.0-12.27.amzn1', 'cpu':'x86_64', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
{'reference':'expat-devel-2.1.0-12.27.amzn1', 'cpu':'i686', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
{'reference':'expat-devel-2.1.0-12.27.amzn1', 'cpu':'x86_64', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE}
];
var flag = 0;
foreach package_array ( pkgs ) {
var reference = NULL;
var release = NULL;
var cpu = NULL;
var el_string = NULL;
var rpm_spec_vers_cmp = NULL;
var allowmaj = NULL;
if (!empty_or_null(package_array['reference'])) reference = package_array['reference'];
if (!empty_or_null(package_array['release'])) release = package_array['release'];
if (!empty_or_null(package_array['cpu'])) cpu = package_array['cpu'];
if (!empty_or_null(package_array['el_string'])) el_string = package_array['el_string'];
if (!empty_or_null(package_array['rpm_spec_vers_cmp'])) rpm_spec_vers_cmp = package_array['rpm_spec_vers_cmp'];
if (!empty_or_null(package_array['allowmaj'])) allowmaj = package_array['allowmaj'];
if (reference && release) {
if (rpm_check(release:release, cpu:cpu, reference:reference, el_string:el_string, rpm_spec_vers_cmp:rpm_spec_vers_cmp, allowmaj:allowmaj)) flag++;
}
}
if (flag)
{
security_report_v4(
port : 0,
severity : SECURITY_HOLE,
extra : rpm_report_get()
);
exit(0);
}
else
{
var tested = pkg_tests_get();
if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
else audit(AUDIT_PACKAGE_NOT_INSTALLED, "expat / expat-debuginfo / expat-devel");
}
CVSS2
Attack Vector
NETWORK
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
PARTIAL
Availability Impact
PARTIAL
AV:N/AC:L/Au:N/C:P/I:P/A:P
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
Percentile
93.0%