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nessusUbuntu Security Notice (C) 2021-2023 Canonical, Inc. / NASL script (C) 2021-2023 and is owned by Tenable, Inc. or an Affiliate thereof.UBUNTU_USN-5088-1.NASL
HistorySep 23, 2021 - 12:00 a.m.

Ubuntu 20.04 LTS : EDK II vulnerabilities (USN-5088-1)

2021-09-2300:00:00
Ubuntu Security Notice (C) 2021-2023 Canonical, Inc. / NASL script (C) 2021-2023 and is owned by Tenable, Inc. or an Affiliate thereof.
www.tenable.com
22

The remote Ubuntu 20.04 LTS / 21.04 host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-5088-1 advisory.

  • NetworkPkg/IScsiDxe has remotely exploitable buffer overflows. (CVE-2021-38575)

  • Insufficient input validation in MdeModulePkg in EDKII may allow an unauthenticated user to potentially enable escalation of privilege, denial of service and/or information disclosure via physical access.
    (CVE-2019-11098)

  • ASN.1 strings are represented internally within OpenSSL as an ASN1_STRING structure which contains a buffer holding the string data and a field holding the buffer length. This contrasts with normal C strings which are repesented as a buffer for the string data which is terminated with a NUL (0) byte. Although not a strict requirement, ASN.1 strings that are parsed using OpenSSL’s own d2i functions (and other similar parsing functions) as well as any string whose value has been set with the ASN1_STRING_set() function will additionally NUL terminate the byte array in the ASN1_STRING structure. However, it is possible for applications to directly construct valid ASN1_STRING structures which do not NUL terminate the byte array by directly setting the data and length fields in the ASN1_STRING array. This can also happen by using the ASN1_STRING_set0() function. Numerous OpenSSL functions that print ASN.1 data have been found to assume that the ASN1_STRING byte array will be NUL terminated, even though this is not guaranteed for strings that have been directly constructed. Where an application requests an ASN.1 structure to be printed, and where that ASN.1 structure contains ASN1_STRINGs that have been directly constructed by the application without NUL terminating the data field, then a read buffer overrun can occur. The same thing can also occur during name constraints processing of certificates (for example if a certificate has been directly constructed by the application instead of loading it via the OpenSSL parsing functions, and the certificate contains non NUL terminated ASN1_STRING structures). It can also occur in the X509_get1_email(), X509_REQ_get1_email() and X509_get1_ocsp() functions. If a malicious actor can cause an application to directly construct an ASN1_STRING and then process it through one of the affected OpenSSL functions then this issue could be hit. This might result in a crash (causing a Denial of Service attack).
    It could also result in the disclosure of private memory contents (such as private keys, or sensitive plaintext). Fixed in OpenSSL 1.1.1l (Affected 1.1.1-1.1.1k). Fixed in OpenSSL 1.0.2za (Affected 1.0.2-1.0.2y). (CVE-2021-3712)

  • Calls to EVP_CipherUpdate, EVP_EncryptUpdate and EVP_DecryptUpdate may overflow the output length argument in some cases where the input length is close to the maximum permissable length for an integer on the platform. In such cases the return value from the function call will be 1 (indicating success), but the output length value will be negative. This could cause applications to behave incorrectly or crash.
    OpenSSL versions 1.1.1i and below are affected by this issue. Users of these versions should upgrade to OpenSSL 1.1.1j. OpenSSL versions 1.0.2x and below are affected by this issue. However OpenSSL 1.0.2 is out of support and no longer receiving public updates. Premium support customers of OpenSSL 1.0.2 should upgrade to 1.0.2y. Other users should upgrade to 1.1.1j. Fixed in OpenSSL 1.1.1j (Affected 1.1.1-1.1.1i).
    Fixed in OpenSSL 1.0.2y (Affected 1.0.2-1.0.2x). (CVE-2021-23840)

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 Ubuntu Security Notice USN-5088-1. The text
# itself is copyright (C) Canonical, Inc. See
# <https://ubuntu.com/security/notices>. Ubuntu(R) is a registered
# trademark of Canonical, Inc.
##

include('deprecated_nasl_level.inc');
include('compat.inc');

if (description)
{
  script_id(153591);
  script_version("1.8");
  script_set_attribute(attribute:"plugin_modification_date", value:"2023/10/20");

  script_cve_id(
    "CVE-2019-11098",
    "CVE-2021-3712",
    "CVE-2021-23840",
    "CVE-2021-38575"
  );
  script_xref(name:"USN", value:"5088-1");
  script_xref(name:"IAVA", value:"2021-A-0395-S");
  script_xref(name:"IAVA", value:"2021-A-0103-S");

  script_name(english:"Ubuntu 20.04 LTS : EDK II vulnerabilities (USN-5088-1)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Ubuntu host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The remote Ubuntu 20.04 LTS / 21.04 host has packages installed that are affected by multiple vulnerabilities as
referenced in the USN-5088-1 advisory.

  - NetworkPkg/IScsiDxe has remotely exploitable buffer overflows. (CVE-2021-38575)

  - Insufficient input validation in MdeModulePkg in EDKII may allow an unauthenticated user to potentially
    enable escalation of privilege, denial of service and/or information disclosure via physical access.
    (CVE-2019-11098)

  - ASN.1 strings are represented internally within OpenSSL as an ASN1_STRING structure which contains a
    buffer holding the string data and a field holding the buffer length. This contrasts with normal C strings
    which are repesented as a buffer for the string data which is terminated with a NUL (0) byte. Although not
    a strict requirement, ASN.1 strings that are parsed using OpenSSL's own d2i functions (and other similar
    parsing functions) as well as any string whose value has been set with the ASN1_STRING_set() function will
    additionally NUL terminate the byte array in the ASN1_STRING structure. However, it is possible for
    applications to directly construct valid ASN1_STRING structures which do not NUL terminate the byte array
    by directly setting the data and length fields in the ASN1_STRING array. This can also happen by using
    the ASN1_STRING_set0() function. Numerous OpenSSL functions that print ASN.1 data have been found to
    assume that the ASN1_STRING byte array will be NUL terminated, even though this is not guaranteed for
    strings that have been directly constructed. Where an application requests an ASN.1 structure to be
    printed, and where that ASN.1 structure contains ASN1_STRINGs that have been directly constructed by the
    application without NUL terminating the data field, then a read buffer overrun can occur. The same thing
    can also occur during name constraints processing of certificates (for example if a certificate has been
    directly constructed by the application instead of loading it via the OpenSSL parsing functions, and the
    certificate contains non NUL terminated ASN1_STRING structures). It can also occur in the
    X509_get1_email(), X509_REQ_get1_email() and X509_get1_ocsp() functions. If a malicious actor can cause an
    application to directly construct an ASN1_STRING and then process it through one of the affected OpenSSL
    functions then this issue could be hit. This might result in a crash (causing a Denial of Service attack).
    It could also result in the disclosure of private memory contents (such as private keys, or sensitive
    plaintext). Fixed in OpenSSL 1.1.1l (Affected 1.1.1-1.1.1k). Fixed in OpenSSL 1.0.2za (Affected
    1.0.2-1.0.2y). (CVE-2021-3712)

  - Calls to EVP_CipherUpdate, EVP_EncryptUpdate and EVP_DecryptUpdate may overflow the output length argument
    in some cases where the input length is close to the maximum permissable length for an integer on the
    platform. In such cases the return value from the function call will be 1 (indicating success), but the
    output length value will be negative. This could cause applications to behave incorrectly or crash.
    OpenSSL versions 1.1.1i and below are affected by this issue. Users of these versions should upgrade to
    OpenSSL 1.1.1j. OpenSSL versions 1.0.2x and below are affected by this issue. However OpenSSL 1.0.2 is out
    of support and no longer receiving public updates. Premium support customers of OpenSSL 1.0.2 should
    upgrade to 1.0.2y. Other users should upgrade to 1.1.1j. Fixed in OpenSSL 1.1.1j (Affected 1.1.1-1.1.1i).
    Fixed in OpenSSL 1.0.2y (Affected 1.0.2-1.0.2x). (CVE-2021-23840)

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://ubuntu.com/security/notices/USN-5088-1");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/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:H/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-2021-38575");

  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:"2021/02/16");
  script_set_attribute(attribute:"patch_publication_date", value:"2021/09/23");
  script_set_attribute(attribute:"plugin_publication_date", value:"2021/09/23");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:20.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:ovmf");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:qemu-efi");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:qemu-efi-aarch64");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:qemu-efi-arm");
  script_set_attribute(attribute:"stig_severity", value:"I");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Ubuntu Local Security Checks");

  script_copyright(english:"Ubuntu Security Notice (C) 2021-2023 Canonical, Inc. / NASL script (C) 2021-2023 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/cpu", "Host/Ubuntu", "Host/Ubuntu/release", "Host/Debian/dpkg-l");

  exit(0);
}

include('debian_package.inc');

if ( ! get_kb_item('Host/local_checks_enabled') ) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var os_release = get_kb_item('Host/Ubuntu/release');
if ( isnull(os_release) ) audit(AUDIT_OS_NOT, 'Ubuntu');
os_release = chomp(os_release);
if (! ('20.04' >< os_release)) audit(AUDIT_OS_NOT, 'Ubuntu 20.04', 'Ubuntu ' + os_release);
if ( ! get_kb_item('Host/Debian/dpkg-l') ) audit(AUDIT_PACKAGE_LIST_MISSING);

var cpu = get_kb_item('Host/cpu');
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ('x86_64' >!< cpu && cpu !~ "^i[3-6]86$" && 's390' >!< cpu && 'aarch64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Ubuntu', cpu);

var pkgs = [
    {'osver': '20.04', 'pkgname': 'ovmf', 'pkgver': '0~20191122.bd85bf54-2ubuntu3.3'},
    {'osver': '20.04', 'pkgname': 'qemu-efi', 'pkgver': '0~20191122.bd85bf54-2ubuntu3.3'},
    {'osver': '20.04', 'pkgname': 'qemu-efi-aarch64', 'pkgver': '0~20191122.bd85bf54-2ubuntu3.3'},
    {'osver': '20.04', 'pkgname': 'qemu-efi-arm', 'pkgver': '0~20191122.bd85bf54-2ubuntu3.3'}
];

var flag = 0;
foreach package_array ( pkgs ) {
  var osver = NULL;
  var pkgname = NULL;
  var pkgver = NULL;
  if (!empty_or_null(package_array['osver'])) osver = package_array['osver'];
  if (!empty_or_null(package_array['pkgname'])) pkgname = package_array['pkgname'];
  if (!empty_or_null(package_array['pkgver'])) pkgver = package_array['pkgver'];
  if (osver && pkgname && pkgver) {
    if (ubuntu_check(osver:osver, pkgname:pkgname, pkgver:pkgver)) flag++;
  }
}

if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_WARNING,
    extra      : ubuntu_report_get()
  );
  exit(0);
}
else
{
  var tested = ubuntu_pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'ovmf / qemu-efi / qemu-efi-aarch64 / qemu-efi-arm');
}