Ubuntu 20.04 LTS : Apache Log4j 2 vulnerability (USN-5197-1)

##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-5197-1. The text
# itself is copyright (C) Canonical, Inc. See
# <https://ubuntu.com/security/notices>. Ubuntu(R) is a registered
# trademark of Canonical, Inc.
##

include('compat.inc');

if (description)
{
  script_id(156104);
  script_version("1.16");
  script_set_attribute(attribute:"plugin_modification_date", value:"2023/10/20");

  script_cve_id("CVE-2021-44228", "CVE-2021-45046");
  script_xref(name:"IAVA", value:"2021-A-0573");
  script_xref(name:"IAVA", value:"2021-A-0597");
  script_xref(name:"IAVA", value:"0001-A-0650");
  script_xref(name:"USN", value:"5197-1");
  script_xref(name:"CISA-KNOWN-EXPLOITED", value:"2021/12/24");
  script_xref(name:"CISA-KNOWN-EXPLOITED", value:"2023/05/22");
  script_xref(name:"CEA-ID", value:"CEA-2021-0052");
  script_xref(name:"CEA-ID", value:"CEA-2023-0004");

  script_name(english:"Ubuntu 20.04 LTS : Apache Log4j 2 vulnerability (USN-5197-1)");

  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 host has a package installed that is affected by multiple vulnerabilities as referenced in
the USN-5197-1 advisory.

  - Apache Log4j2 2.0-beta9 through 2.12.1 and 2.13.0 through 2.15.0 JNDI features used in configuration, log
    messages, and parameters do not protect against attacker controlled LDAP and other JNDI related endpoints.
    An attacker who can control log messages or log message parameters can execute arbitrary code loaded from
    LDAP servers when message lookup substitution is enabled. From log4j 2.15.0, this behavior has been
    disabled by default. From version 2.16.0, this functionality has been completely removed. Note that this
    vulnerability is specific to log4j-core and does not affect log4net, log4cxx, or other Apache Logging
    Services projects. (CVE-2021-44228)

  - It was found that the fix to address CVE-2021-44228 in Apache Log4j 2.15.0 was incomplete in certain non-
    default configurations. This could allows attackers with control over Thread Context Map (MDC) input data
    when the logging configuration uses a non-default Pattern Layout with either a Context Lookup (for
    example, $${ctx:loginId}) or a Thread Context Map pattern (%X, %mdc, or %MDC) to craft malicious input
    data using a JNDI Lookup pattern resulting in a denial of service (DOS) attack. Log4j 2.15.0 makes a best-
    effort attempt to restrict JNDI LDAP lookups to localhost by default. Log4j 2.16.0 fixes this issue by
    removing support for message lookup patterns and disabling JNDI functionality by default. (CVE-2021-45046)

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-5197-1");
  script_set_attribute(attribute:"solution", value:
"Update the affected liblog4j2-java package.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:H/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:H/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2021-44228");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");
  script_set_attribute(attribute:"exploit_framework_core", value:"true");
  script_set_attribute(attribute:"exploited_by_malware", value:"true");
  script_set_attribute(attribute:"exploit_framework_canvas", value:"true");
  script_set_attribute(attribute:"canvas_package", value:"CANVAS");

  script_set_attribute(attribute:"vuln_publication_date", value:"2021/12/10");
  script_set_attribute(attribute:"patch_publication_date", value:"2021/12/15");
  script_set_attribute(attribute:"plugin_publication_date", value:"2021/12/15");

  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:liblog4j2-java");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  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': 'liblog4j2-java', 'pkgver': '2.16.0-0.20.04.1'}
];

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_HOLE,
    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, 'liblog4j2-java');
}