Oracle Linux 8 : squid:4 (ELSA-2020-2041)

##
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Oracle Linux Security Advisory ELSA-2020-2041.
##

include('compat.inc');

if (description)
{
  script_id(136599);
  script_version("1.6");
  script_set_attribute(attribute:"plugin_modification_date", value:"2021/05/11");

  script_cve_id("CVE-2019-12519", "CVE-2019-12525", "CVE-2020-11945");
  script_bugtraq_id(109382);

  script_name(english:"Oracle Linux 8 : squid:4 (ELSA-2020-2041)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Oracle Linux host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The remote Oracle Linux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the
ELSA-2020-2041 advisory.

  - An issue was discovered in Squid through 4.7. When handling the tag esi:when when ESI is enabled, Squid
    calls ESIExpression::Evaluate. This function uses a fixed stack buffer to hold the expression while it's
    being evaluated. When processing the expression, it could either evaluate the top of the stack, or add a
    new member to the stack. When adding a new member, there is no check to ensure that the stack won't
    overflow. (CVE-2019-12519)

  - An issue was discovered in Squid 3.3.9 through 3.5.28 and 4.x through 4.7. When Squid is configured to use
    Digest authentication, it parses the header Proxy-Authorization. It searches for certain tokens such as
    domain, uri, and qop. Squid checks if this token's value starts with a quote and ends with one. If so, it
    performs a memcpy of its length minus 2. Squid never checks whether the value is just a single quote
    (which would satisfy its requirements), leading to a memcpy of its length minus 1. (CVE-2019-12525)

  - An issue was discovered in Squid before 5.0.2. A remote attacker can replay a sniffed Digest
    Authentication nonce to gain access to resources that are otherwise forbidden. This occurs because the
    attacker can overflow the nonce reference counter (a short integer). Remote code execution may occur if
    the pooled token credentials are freed (instead of replayed as valid credentials). (CVE-2020-11945)

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://linux.oracle.com/errata/ELSA-2020-2041.html");
  script_set_attribute(attribute:"solution", value:
"Update the affected libecap, libecap-devel and / or squid packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/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:N/AC:L/PR:N/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:"cvss_score_source", value:"CVE-2020-11945");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");

  script_set_attribute(attribute:"vuln_publication_date", value:"2019/07/11");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/05/12");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/08/13");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:oracle:linux:8");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:libecap");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:libecap-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:squid");
  script_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2020-2021 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/OracleLinux", "Host/RedHat/release", "Host/RedHat/rpm-list", "Host/local_checks_enabled");

  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);
if (!get_kb_item('Host/OracleLinux')) audit(AUDIT_OS_NOT, 'Oracle Linux');
release = get_kb_item("Host/RedHat/release");
if (isnull(release) || !pregmatch(pattern: "Oracle (?:Linux Server|Enterprise Linux)", string:release)) audit(AUDIT_OS_NOT, 'Oracle Linux');
os_ver = pregmatch(pattern: "Oracle (?:Linux Server|Enterprise Linux) .*release ([0-9]+(\.[0-9]+)?)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, 'Oracle Linux');
os_ver = os_ver[1];
if (! preg(pattern:"^8([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, 'Oracle Linux 8', 'Oracle Linux ' + os_ver);

if (!get_kb_item('Host/RedHat/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, 'Oracle Linux', cpu);

module_ver = get_kb_item('Host/RedHat/appstream/squid');
if (isnull(module_ver)) audit(AUDIT_PACKAGE_NOT_INSTALLED, 'Module squid:4');
if ('4' >!< module_ver) audit(AUDIT_PACKAGE_NOT_AFFECTED, 'Module squid:' + module_ver);

appstreams = {
    'squid:4': [
      {'reference':'libecap-1.0.1-2.module+el8.1.0+5405+03b963f4', 'cpu':'aarch64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'libecap-1.0.1-2.module+el8.1.0+5405+03b963f4', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'libecap-devel-1.0.1-2.module+el8.1.0+5405+03b963f4', 'cpu':'aarch64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'libecap-devel-1.0.1-2.module+el8.1.0+5405+03b963f4', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'squid-4.4-8.module+el8.2.0+7611+d512f060.1', 'cpu':'aarch64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'7'},
      {'reference':'squid-4.4-8.module+el8.2.0+7611+d512f060.1', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'7'}
    ]
};

flag = 0;
appstreams_found = 0;
foreach module (keys(appstreams)) {
  appstream = NULL;
  appstream_name = NULL;
  appstream_version = NULL;
  appstream_split = split(module, sep:':', keep:FALSE);
  if (!empty_or_null(appstream_split)) {
    appstream_name = appstream_split[0];
    appstream_version = appstream_split[1];
    if (!empty_or_null(appstream_name)) appstream = get_one_kb_item('Host/RedHat/appstream/' + appstream_name);
  }
  if (!empty_or_null(appstream) && appstream_version == appstream || appstream_name == 'all') {
    appstreams_found++;
    foreach package_array ( appstreams[module] ) {
      reference = NULL;
      release = NULL;
      sp = NULL;
      cpu = NULL;
      el_string = NULL;
      rpm_spec_vers_cmp = NULL;
      epoch = NULL;
      allowmaj = NULL;
      if (!empty_or_null(package_array['reference'])) reference = package_array['reference'];
      if (!empty_or_null(package_array['release'])) release = 'EL' + package_array['release'];
      if (!empty_or_null(package_array['sp'])) sp = package_array['sp'];
      if (!empty_or_null(package_array['cpu'])) cpu = package_array['cpu'];
      if (!empty_or_null(package_array['el_string'])) el_string = package_array['el_string'];
      if (!empty_or_null(package_array['rpm_spec_vers_cmp'])) rpm_spec_vers_cmp = package_array['rpm_spec_vers_cmp'];
      if (!empty_or_null(package_array['epoch'])) epoch = package_array['epoch'];
      if (!empty_or_null(package_array['allowmaj'])) allowmaj = package_array['allowmaj'];
      if (reference && release) {
        if (rpm_check(release:release, sp:sp, cpu:cpu, reference:reference, epoch:epoch, el_string:el_string, rpm_spec_vers_cmp:rpm_spec_vers_cmp, allowmaj:allowmaj)) flag++;
      }
    }
  }
}

if (!appstreams_found) audit(AUDIT_PACKAGE_NOT_INSTALLED, 'Module squid:4');

if (flag)
{
  security_report_v4(
      port       : 0,
      severity   : SECURITY_HOLE,
      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, 'libecap / libecap-devel / squid');
}