CentOS: Security Advisory for shim-unsigned-ia32 (CESA-2020:3217)

# Copyright (C) 2020 Greenbone Networks GmbH
# Some text descriptions might be excerpted from (a) referenced
# source(s), and are Copyright (C) by the respective right holder(s).
#
# SPDX-License-Identifier: GPL-2.0-or-later
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.883265");
  script_version("2021-07-06T02:00:40+0000");
  script_cve_id("CVE-2020-10713", "CVE-2020-14308", "CVE-2020-14309", "CVE-2020-14310", "CVE-2020-14311", "CVE-2020-15705", "CVE-2020-15706", "CVE-2020-15707");
  script_tag(name:"cvss_base", value:"4.6");
  script_tag(name:"cvss_base_vector", value:"AV:L/AC:L/Au:N/C:P/I:P/A:P");
  script_tag(name:"last_modification", value:"2021-07-06 02:00:40 +0000 (Tue, 06 Jul 2021)");
  script_tag(name:"severity_vector", value:"CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H");
  script_tag(name:"severity_origin", value:"NVD");
  script_tag(name:"severity_date", value:"2021-05-01 02:15:00 +0000 (Sat, 01 May 2021)");
  script_tag(name:"creation_date", value:"2020-07-30 03:01:24 +0000 (Thu, 30 Jul 2020)");
  script_name("CentOS: Security Advisory for shim-unsigned-ia32 (CESA-2020:3217)");
  script_category(ACT_GATHER_INFO);
  script_copyright("Copyright (C) 2020 Greenbone Networks GmbH");
  script_family("CentOS Local Security Checks");
  script_dependencies("gather-package-list.nasl");
  script_mandatory_keys("ssh/login/centos", "ssh/login/rpms", re:"ssh/login/release=CentOS7");

  script_xref(name:"CESA", value:"2020:3217");
  script_xref(name:"URL", value:"https://lists.centos.org/pipermail/centos-announce/2020-July/035781.html");

  script_tag(name:"summary", value:"The remote host is missing an update for the 'shim-unsigned-ia32'
  package(s) announced via the CESA-2020:3217 advisory.");

  script_tag(name:"vuldetect", value:"Checks if a vulnerable package version is present on the target host.");

  script_tag(name:"insight", value:"The grub2 packages provide version 2 of the Grand Unified Boot Loader
(GRUB), a highly configurable and customizable boot loader with modular
architecture. The packages support a variety of kernel formats, file
systems, computer architectures, and hardware devices.

The shim package contains a first-stage UEFI boot loader that handles
chaining to a trusted full boot loader under secure boot environments.

The fwupdate packages provide a service that allows session software to
update device firmware.

Security Fix(es):

  * grub2: Crafted grub.cfg file can lead to arbitrary code execution during
boot process (CVE-2020-10713)

  * grub2: grub_malloc does not validate allocation size allowing for
arithmetic overflow and subsequent heap-based buffer overflow
(CVE-2020-14308)

  * grub2: Integer overflow in grub_squash_read_symlink may lead to
heap-based buffer overflow (CVE-2020-14309)

  * grub2: Integer overflow read_section_as_string may lead to heap-based
buffer overflow (CVE-2020-14310)

  * grub2: Integer overflow in grub_ext2_read_link leads to heap-based buffer
overflow (CVE-2020-14311)

  * grub2: Fail kernel validation without shim protocol (CVE-2020-15705)

  * grub2: Use-after-free redefining a function whilst the same function is
already executing (CVE-2020-15706)

  * grub2: Integer overflow in initrd size handling (CVE-2020-15707)

For more details about the security issue(s), including the impact, a CVSS
score, acknowledgments, and other related information, refer to the CVE
page(s) listed in the References section.

Bug Fix(es):

  * grub2 doesn't handle relative paths correctly for UEFI HTTP Boot
(BZ#1616395)

  * UEFI HTTP boot over IPv6 does not work (BZ#1732765)

Users of grub2 are advised to upgrade to these updated packages, which fix
these bugs.");

  script_tag(name:"affected", value:"'shim-unsigned-ia32' package(s) on CentOS 7.");

  script_tag(name:"solution", value:"Please install the updated package(s).");

  script_tag(name:"solution_type", value:"VendorFix");
  script_tag(name:"qod_type", value:"package");

  exit(0);
}

include("revisions-lib.inc");
include("pkg-lib-rpm.inc");

release = rpm_get_ssh_release();
if(!release)
  exit(0);

res = "";
report = "";

if(release == "CentOS7") {

  if(!isnull(res = isrpmvuln(pkg:"shim-unsigned-ia32", rpm:"shim-unsigned-ia32~15~7.el7_9", rls:"CentOS7"))) {
    report += res;
  }

  if(!isnull(res = isrpmvuln(pkg:"shim-unsigned-x64", rpm:"shim-unsigned-x64~15~7.el7_9", rls:"CentOS7"))) {
    report += res;
  }

  if(!isnull(res = isrpmvuln(pkg:"shim", rpm:"shim~15~7.el7_9", rls:"CentOS7"))) {
    report += res;
  }

  if(report != "") {
    security_message(data:report);
  } else if(__pkg_match) {
    exit(99);
  }
  exit(0);
}

exit(0);