An out-of-bounds access issue was found in the way Linux kernel’s KVM hypervisor implements the Coalesced MMIO write operation. It operates on an MMIO ring buffer ‘struct kvm_coalesced_mmio’ object, wherein write indices ‘ring->first’ and ‘ring->last’ value could be supplied by a host user-space process. An unprivileged host user or process with access to ‘/dev/kvm’ device could use this flaw to crash the host kernel, resulting in a denial of service or potentially escalating privileges on the system. (CVE-2019-14821)
A buffer overflow flaw was found in the way Linux kernel’s vhost functionality that translates virtqueue buffers to IOVs, logged the buffer descriptors during migration. A privileged guest user able to pass descriptors with invalid length to the host when migration is underway, could use this flaw to increase their privileges on the host.(CVE-2019-14835)
#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux AMI Security Advisory ALAS-2019-1293.
#
include("compat.inc");
if (description)
{
script_id(129407);
script_version("1.5");
script_set_attribute(attribute:"plugin_modification_date", value:"2022/05/23");
script_cve_id("CVE-2019-14821", "CVE-2019-14835");
script_xref(name:"ALAS", value:"2019-1293");
script_name(english:"Amazon Linux AMI : kernel (ALAS-2019-1293)");
script_summary(english:"Checks rpm output for the updated packages");
script_set_attribute(
attribute:"synopsis",
value:"The remote Amazon Linux AMI host is missing a security update."
);
script_set_attribute(
attribute:"description",
value:
"An out-of-bounds access issue was found in the way Linux kernel's KVM
hypervisor implements the Coalesced MMIO write operation. It operates
on an MMIO ring buffer 'struct kvm_coalesced_mmio' object, wherein
write indices 'ring->first' and 'ring->last' value could be supplied
by a host user-space process. An unprivileged host user or process
with access to '/dev/kvm' device could use this flaw to crash the host
kernel, resulting in a denial of service or potentially escalating
privileges on the system. (CVE-2019-14821)
A buffer overflow flaw was found in the way Linux kernel's vhost
functionality that translates virtqueue buffers to IOVs, logged the
buffer descriptors during migration. A privileged guest user able to
pass descriptors with invalid length to the host when migration is
underway, could use this flaw to increase their privileges on the
host.(CVE-2019-14835)"
);
script_set_attribute(
attribute:"see_also",
value:"https://alas.aws.amazon.com/ALAS-2019-1293.html"
);
script_set_attribute(
attribute:"solution",
value:"Run 'yum update kernel' to update your system."
);
script_set_cvss_base_vector("CVSS2#AV:L/AC:L/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:L/UI:N/S:C/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-2019-14835");
script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
script_set_attribute(attribute:"exploit_available", value:"false");
script_set_attribute(attribute:"plugin_type", value:"local");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:kernel");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:kernel-debuginfo");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:kernel-debuginfo-common-i686");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:kernel-debuginfo-common-x86_64");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:kernel-devel");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:kernel-headers");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:kernel-tools");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:kernel-tools-debuginfo");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:kernel-tools-devel");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:perf");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:perf-debuginfo");
script_set_attribute(attribute:"cpe", value:"cpe:/o:amazon:linux");
script_set_attribute(attribute:"vuln_publication_date", value:"2019/09/17");
script_set_attribute(attribute:"patch_publication_date", value:"2019/09/25");
script_set_attribute(attribute:"plugin_publication_date", value:"2019/09/30");
script_set_attribute(attribute:"generated_plugin", value:"current");
script_end_attributes();
script_category(ACT_GATHER_INFO);
script_copyright(english:"This script is Copyright (C) 2019-2022 and is owned by Tenable, Inc. or an Affiliate thereof.");
script_family(english:"Amazon Linux Local Security Checks");
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);
release = get_kb_item("Host/AmazonLinux/release");
if (isnull(release) || !strlen(release)) audit(AUDIT_OS_NOT, "Amazon Linux");
os_ver = pregmatch(pattern: "^AL(A|\d)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Amazon Linux");
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);
flag = 0;
if (rpm_check(release:"ALA", reference:"kernel-4.14.146-93.123.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"kernel-debuginfo-4.14.146-93.123.amzn1")) flag++;
if (rpm_check(release:"ALA", cpu:"i686", reference:"kernel-debuginfo-common-i686-4.14.146-93.123.amzn1")) flag++;
if (rpm_check(release:"ALA", cpu:"x86_64", reference:"kernel-debuginfo-common-x86_64-4.14.146-93.123.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"kernel-devel-4.14.146-93.123.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"kernel-headers-4.14.146-93.123.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"kernel-tools-4.14.146-93.123.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"kernel-tools-debuginfo-4.14.146-93.123.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"kernel-tools-devel-4.14.146-93.123.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"perf-4.14.146-93.123.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"perf-debuginfo-4.14.146-93.123.amzn1")) flag++;
if (flag)
{
if (report_verbosity > 0) security_hole(port:0, extra:rpm_report_get());
else security_hole(0);
exit(0);
}
else
{
tested = pkg_tests_get();
if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
else audit(AUDIT_PACKAGE_NOT_INSTALLED, "kernel / kernel-debuginfo / kernel-debuginfo-common-i686 / etc");
}