Ubuntu: Security Advisory (USN-4432-2)

# SPDX-FileCopyrightText: 2020 Greenbone AG
# 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-only

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.844526");
  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:"creation_date", value:"2020-08-05 03:00:27 +0000 (Wed, 05 Aug 2020)");
  script_version("2024-02-02T05:06:07+0000");
  script_tag(name:"last_modification", value:"2024-02-02 05:06:07 +0000 (Fri, 02 Feb 2024)");
  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:"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:"2020-08-05 14:34:24 +0000 (Wed, 05 Aug 2020)");

  script_name("Ubuntu: Security Advisory (USN-4432-2)");
  script_category(ACT_GATHER_INFO);
  script_copyright("Copyright (C) 2020 Greenbone AG");
  script_family("Ubuntu Local Security Checks");
  script_dependencies("gather-package-list.nasl");
  script_mandatory_keys("ssh/login/ubuntu_linux", "ssh/login/packages", re:"ssh/login/release=UBUNTU(14\.04\ LTS|16\.04\ LTS|18\.04\ LTS|20\.04\ LTS)");

  script_xref(name:"Advisory-ID", value:"USN-4432-2");
  script_xref(name:"URL", value:"https://ubuntu.com/security/notices/USN-4432-2");
  script_xref(name:"URL", value:"https://launchpad.net/bugs/1889556");
  script_xref(name:"URL", value:"https://wiki.ubuntu.com/SecurityTeam/KnowledgeBase/GRUB2SecureBootBypass");

  script_tag(name:"summary", value:"The remote host is missing an update for the 'grub2, grub2-signed' package(s) announced via the USN-4432-2 advisory.");

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

  script_tag(name:"insight", value:"USN-4432-1 fixed vulnerabilities in GRUB2 affecting Secure Boot
environments. Unfortunately, the update introduced regressions for
some BIOS systems (either pre-UEFI or UEFI configured in Legacy mode),
preventing them from successfully booting. This update addresses
the issue.

Users with BIOS systems that installed GRUB2 versions from USN-4432-1
should verify that their GRUB2 installation has a correct understanding
of their boot device location and installed the boot loader correctly.

We apologize for the inconvenience.

Original advisory details:

 Jesse Michael and Mickey Shkatov discovered that the configuration parser
 in GRUB2 did not properly exit when errors were discovered, resulting in
 heap-based buffer overflows. A local attacker could use this to execute
 arbitrary code and bypass UEFI Secure Boot restrictions. (CVE-2020-10713)

 Chris Coulson discovered that the GRUB2 function handling code did not
 properly handle a function being redefined, leading to a use-after-free
 vulnerability. A local attacker could use this to execute arbitrary code
 and bypass UEFI Secure Boot restrictions. (CVE-2020-15706)

 Chris Coulson discovered that multiple integer overflows existed in GRUB2
 when handling certain filesystems or font files, leading to heap-based
 buffer overflows. A local attacker could use these to execute arbitrary
 code and bypass UEFI Secure Boot restrictions. (CVE-2020-14309,
 CVE-2020-14310, CVE-2020-14311)

 It was discovered that the memory allocator for GRUB2 did not validate
 allocation size, resulting in multiple integer overflows and heap-based
 buffer overflows when handling certain filesystems, PNG images or disk
 metadata. A local attacker could use this to execute arbitrary code and
 bypass UEFI Secure Boot restrictions. (CVE-2020-14308)

 Mathieu Trudel-Lapierre discovered that in certain situations, GRUB2
 failed to validate kernel signatures. A local attacker could use this
 to bypass Secure Boot restrictions. (CVE-2020-15705)

 Colin Watson and Chris Coulson discovered that an integer overflow
 existed in GRUB2 when handling the initrd command, leading to a heap-based
 buffer overflow. A local attacker could use this to execute arbitrary code
 and bypass UEFI Secure Boot restrictions. (CVE-2020-15707)");

  script_tag(name:"affected", value:"'grub2, grub2-signed' package(s) on Ubuntu 14.04, Ubuntu 16.04, Ubuntu 18.04, Ubuntu 20.04.");

  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-deb.inc");

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

res = "";
report = "";

if(release == "UBUNTU14.04 LTS") {

  if(!isnull(res = isdpkgvuln(pkg:"grub-efi-amd64-bin", ver:"2.02~beta2-9ubuntu1.21", rls:"UBUNTU14.04 LTS"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"grub-efi-amd64-signed", ver:"1.34.20+2.02~beta2-9ubuntu1.21", rls:"UBUNTU14.04 LTS"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"grub-efi-arm-bin", ver:"2.02~beta2-9ubuntu1.21", rls:"UBUNTU14.04 LTS"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"grub-efi-arm64-bin", ver:"2.02~beta2-9ubuntu1.21", rls:"UBUNTU14.04 LTS"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"grub-efi-ia32-bin", ver:"2.02~beta2-9ubuntu1.21", rls:"UBUNTU14.04 LTS"))) {
    report += res;
  }

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

if(release == "UBUNTU16.04 LTS") {

  if(!isnull(res = isdpkgvuln(pkg:"grub-efi-amd64-bin", ver:"2.02~beta2-36ubuntu3.27", rls:"UBUNTU16.04 LTS"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"grub-efi-amd64-signed", ver:"1.66.27+2.02~beta2-36ubuntu3.27", rls:"UBUNTU16.04 LTS"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"grub-efi-arm-bin", ver:"2.02~beta2-36ubuntu3.27", rls:"UBUNTU16.04 LTS"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"grub-efi-arm64-bin", ver:"2.02~beta2-36ubuntu3.27", rls:"UBUNTU16.04 LTS"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"grub-efi-arm64-signed", ver:"1.66.27+2.02~beta2-36ubuntu3.27", rls:"UBUNTU16.04 LTS"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"grub-efi-ia32-bin", ver:"2.02~beta2-36ubuntu3.27", rls:"UBUNTU16.04 LTS"))) {
    report += res;
  }

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

if(release == "UBUNTU18.04 LTS") {

  if(!isnull(res = isdpkgvuln(pkg:"grub-efi-amd64-bin", ver:"2.02-2ubuntu8.17", rls:"UBUNTU18.04 LTS"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"grub-efi-amd64-signed", ver:"1.93.19+2.02-2ubuntu8.17", rls:"UBUNTU18.04 LTS"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"grub-efi-arm-bin", ver:"2.02-2ubuntu8.17", rls:"UBUNTU18.04 LTS"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"grub-efi-arm64-bin", ver:"2.02-2ubuntu8.17", rls:"UBUNTU18.04 LTS"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"grub-efi-arm64-signed", ver:"1.93.19+2.02-2ubuntu8.17", rls:"UBUNTU18.04 LTS"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"grub-efi-ia32-bin", ver:"2.02-2ubuntu8.17", rls:"UBUNTU18.04 LTS"))) {
    report += res;
  }

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

if(release == "UBUNTU20.04 LTS") {

  if(!isnull(res = isdpkgvuln(pkg:"grub-efi-amd64-bin", ver:"2.04-1ubuntu26.2", rls:"UBUNTU20.04 LTS"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"grub-efi-amd64-signed", ver:"1.142.4+2.04-1ubuntu26.2", rls:"UBUNTU20.04 LTS"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"grub-efi-arm-bin", ver:"2.04-1ubuntu26.2", rls:"UBUNTU20.04 LTS"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"grub-efi-arm64-bin", ver:"2.04-1ubuntu26.2", rls:"UBUNTU20.04 LTS"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"grub-efi-arm64-signed", ver:"1.142.4+2.04-1ubuntu26.2", rls:"UBUNTU20.04 LTS"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"grub-efi-ia32-bin", ver:"2.04-1ubuntu26.2", rls:"UBUNTU20.04 LTS"))) {
    report += res;
  }

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

exit(0);