EulerOS Virtualization for ARM 64 3.0.6.0 : grub2 (EulerOS-SA-2020-2000)

2020-09-29T00:00:00
ID EULEROS_SA-2020-2000.NASL
Type nessus
Reporter This script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.
Modified 2020-09-29T00:00:00

Description

According to the versions of the grub2 packages installed, the EulerOS Virtualization for ARM 64 installation on the remote host is affected by the following vulnerabilities :

  • Integer overflows were discovered in the functions grub_cmd_initrd and grub_initrd_init in the efilinux component of GRUB2, as shipped in Debian, Red Hat, and Ubuntu (the functionality is not included in GRUB2 upstream), leading to a heap-based buffer overflow. These could be triggered by an extremely large number of arguments to the initrd command on 32-bit architectures, or a crafted filesystem with very large files on any architecture. An attacker could use this to execute arbitrary code and bypass UEFI Secure Boot restrictions. This issue affects GRUB2 version 2.04 and prior versions.(CVE-2020-15707)

  • GRUB2 contains a race condition in grub_script_function_create() leading to a use-after-free vulnerability which can be triggered by redefining a function whilst the same function is already executing, leading to arbitrary code execution and secure boot restriction bypass. This issue affects GRUB2 version 2.04 and prior versions.(CVE-2020-15706)

  • There is an issue with grub2 before version 2.06 while handling symlink on ext filesystems. A filesystem containing a symbolic link with an inode size of UINT32_MAX causes an arithmetic overflow leading to a zero-sized memory allocation with subsequent heap-based buffer overflow.(CVE-2020-14311)

  • There is an issue on grub2 before version 2.06 at function read_section_as_string(). It expects a font name to be at max UINT32_MAX - 1 length in bytes but it doesn't verify it before proceed with buffer allocation to read the value from the font value. An attacker may leverage that by crafting a malicious font file which has a name with UINT32_MAX, leading to read_section_as_string() to an arithmetic overflow, zero-sized allocation and further heap-based buffer overflow.(CVE-2020-14310)

  • There's an issue with grub2 in all versions before 2.06 when handling squashfs filesystems containing a symbolic link with name length of UINT32 bytes in size. The name size leads to an arithmetic overflow leading to a zero-size allocation further causing a heap-based buffer overflow with attacker controlled data.(CVE-2020-14309)

  • In grub2 versions before 2.06 the grub memory allocator doesn't check for possible arithmetic overflows on the requested allocation size. This leads the function to return invalid memory allocations which can be further used to cause possible integrity, confidentiality and availability impacts during the boot process.(CVE-2020-14308)

  • GRUB2 fails to validate kernel signature when booted directly without shim, allowing secure boot to be bypassed. This only affects systems where the kernel signing certificate has been imported directly into the secure boot database and the GRUB image is booted directly without the use of shim. This issue affects GRUB2 version 2.04 and prior versions.(CVE-2020-15705)

Note that Tenable Network Security has extracted the preceding description block directly from the EulerOS security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

                                        
                                            #%NASL_MIN_LEVEL 80502
#
# (C) Tenable Network Security, Inc.
#

include("compat.inc");

if (description)
{
  script_id(140948);
  script_version("1.3");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/11/13");

  script_cve_id(
    "CVE-2020-14308",
    "CVE-2020-14309",
    "CVE-2020-14310",
    "CVE-2020-14311",
    "CVE-2020-15705",
    "CVE-2020-15706",
    "CVE-2020-15707"
  );

  script_name(english:"EulerOS Virtualization for ARM 64 3.0.6.0 : grub2 (EulerOS-SA-2020-2000)");
  script_summary(english:"Checks the rpm output for the updated packages.");

  script_set_attribute(attribute:"synopsis", value:
"The remote EulerOS Virtualization for ARM 64 host is missing multiple security
updates.");
  script_set_attribute(attribute:"description", value:
"According to the versions of the grub2 packages installed, the
EulerOS Virtualization for ARM 64 installation on the remote host is
affected by the following vulnerabilities :

  - Integer overflows were discovered in the functions
    grub_cmd_initrd and grub_initrd_init in the efilinux
    component of GRUB2, as shipped in Debian, Red Hat, and
    Ubuntu (the functionality is not included in GRUB2
    upstream), leading to a heap-based buffer overflow.
    These could be triggered by an extremely large number
    of arguments to the initrd command on 32-bit
    architectures, or a crafted filesystem with very large
    files on any architecture. An attacker could use this
    to execute arbitrary code and bypass UEFI Secure Boot
    restrictions. This issue affects GRUB2 version 2.04 and
    prior versions.(CVE-2020-15707)

  - GRUB2 contains a race condition in
    grub_script_function_create() leading to a
    use-after-free vulnerability which can be triggered by
    redefining a function whilst the same function is
    already executing, leading to arbitrary code execution
    and secure boot restriction bypass. This issue affects
    GRUB2 version 2.04 and prior versions.(CVE-2020-15706)

  - There is an issue with grub2 before version 2.06 while
    handling symlink on ext filesystems. A filesystem
    containing a symbolic link with an inode size of
    UINT32_MAX causes an arithmetic overflow leading to a
    zero-sized memory allocation with subsequent heap-based
    buffer overflow.(CVE-2020-14311)

  - There is an issue on grub2 before version 2.06 at
    function read_section_as_string(). It expects a font
    name to be at max UINT32_MAX - 1 length in bytes but it
    doesn't verify it before proceed with buffer allocation
    to read the value from the font value. An attacker may
    leverage that by crafting a malicious font file which
    has a name with UINT32_MAX, leading to
    read_section_as_string() to an arithmetic overflow,
    zero-sized allocation and further heap-based buffer
    overflow.(CVE-2020-14310)

  - There's an issue with grub2 in all versions before 2.06
    when handling squashfs filesystems containing a
    symbolic link with name length of UINT32 bytes in size.
    The name size leads to an arithmetic overflow leading
    to a zero-size allocation further causing a heap-based
    buffer overflow with attacker controlled
    data.(CVE-2020-14309)

  - In grub2 versions before 2.06 the grub memory allocator
    doesn't check for possible arithmetic overflows on the
    requested allocation size. This leads the function to
    return invalid memory allocations which can be further
    used to cause possible integrity, confidentiality and
    availability impacts during the boot
    process.(CVE-2020-14308)

  - GRUB2 fails to validate kernel signature when booted
    directly without shim, allowing secure boot to be
    bypassed. This only affects systems where the kernel
    signing certificate has been imported directly into the
    secure boot database and the GRUB image is booted
    directly without the use of shim. This issue affects
    GRUB2 version 2.04 and prior versions.(CVE-2020-15705)

Note that Tenable Network Security has extracted the preceding
description block directly from the EulerOS security advisory. Tenable
has attempted to automatically clean and format it as much as possible
without introducing additional issues.");
  # https://developer.huaweicloud.com/ict/en/site-euleros/euleros/security-advisories/EulerOS-SA-2020-2000
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?1436ffb8");
  script_set_attribute(attribute:"solution", value:
"Update the affected grub2 packages.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:P/I:P/A:P");
  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:H/UI:N/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:"exploitability_ease", value:"No known exploits are available");

  script_set_attribute(attribute:"patch_publication_date", value:"2020/09/25");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/09/29");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:huawei:euleros:grub2-common");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:huawei:euleros:grub2-efi-aa64");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:huawei:euleros:grub2-efi-aa64-modules");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:huawei:euleros:grub2-tools");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:huawei:euleros:grub2-tools-extra");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:huawei:euleros:grub2-tools-minimal");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:huawei:euleros:uvp:3.0.6.0");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Huawei 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");
  script_require_keys("Host/local_checks_enabled", "Host/cpu", "Host/EulerOS/release", "Host/EulerOS/rpm-list", "Host/EulerOS/uvp_version");

  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/EulerOS/release");
if (isnull(release) || release !~ "^EulerOS") audit(AUDIT_OS_NOT, "EulerOS");
uvp = get_kb_item("Host/EulerOS/uvp_version");
if (uvp != "3.0.6.0") audit(AUDIT_OS_NOT, "EulerOS Virtualization 3.0.6.0");
if (!get_kb_item("Host/EulerOS/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);

cpu = get_kb_item("Host/cpu");
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ("x86_64" >!< cpu && cpu !~ "^i[3-6]86$" && "aarch64" >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "EulerOS", cpu);
if ("aarch64" >!< cpu) audit(AUDIT_ARCH_NOT, "aarch64", cpu);

flag = 0;

pkgs = ["grub2-common-2.02-62.h27.eulerosv2r8",
        "grub2-efi-aa64-2.02-62.h27.eulerosv2r8",
        "grub2-efi-aa64-modules-2.02-62.h27.eulerosv2r8",
        "grub2-tools-2.02-62.h27.eulerosv2r8",
        "grub2-tools-extra-2.02-62.h27.eulerosv2r8",
        "grub2-tools-minimal-2.02-62.h27.eulerosv2r8"];

foreach (pkg in pkgs)
  if (rpm_check(release:"EulerOS-2.0", reference:pkg)) flag++;

if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_WARNING,
    extra      : rpm_report_get()
  );
  exit(0);
}
else
{
  tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "grub2");
}