CentOS Linux 6 [TuxCare] Security Update: squid34 Multiple Vulnerabilities (CENTOS6:CLSA-2026:1777541147)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
##

include('compat.inc');

if (description)
{
  script_id(361595);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/10/01");

  script_cve_id(
    "CVE-2018-19131",
    "CVE-2018-19132",
    "CVE-2018-1000027",
    "CVE-2019-12523",
    "CVE-2019-12525",
    "CVE-2019-12528",
    "CVE-2019-12529",
    "CVE-2019-13345",
    "CVE-2019-18677",
    "CVE-2019-18678",
    "CVE-2019-18679",
    "CVE-2019-18860"
  );
  script_xref(name:"CLSA", value:"2026:1777541147");

  script_name(english:"CentOS Linux 6 [TuxCare] Security Update: squid34 Multiple Vulnerabilities (CENTOS6:CLSA-2026:1777541147)");

  script_set_attribute(attribute:"synopsis", value:
"The CentOS Linux host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The CentOS Linux 6 host has a package installed that is affected by multiple vulnerabilities as referenced in the
TuxCare CENTOS6:CLSA-2026:1777541147 advisory.

  - The Squid Software Foundation Squid HTTP Caching Proxy version prior to version 4.0.23 contains a NULL
    Pointer Dereference vulnerability in HTTP Response X-Forwarded-For header processing that can result in
    Denial of Service to all clients of the proxy. This attack appear to be exploitable via Remote HTTP server
    responding with an X-Forwarded-For header to certain types of HTTP request. This vulnerability appears to
    have been fixed in 4.0.23 and later. (CVE-2018-1000027)

  - Squid before 4.4 has XSS via a crafted X.509 certificate during HTTP(S) error page generation for
    certificate errors. (CVE-2018-19131)

  - Squid before 4.4, when SNMP is enabled, allows a denial of service (Memory Leak) via an SNMP packet.
    (CVE-2018-19132)

  - An issue was discovered in Squid before 4.9. When handling a URN request, a corresponding HTTP request is
    made. This HTTP request doesn't go through the access checks that incoming HTTP requests go through. This
    causes all access checks to be bypassed and allows access to restricted HTTP servers, e.g., an attacker
    can connect to HTTP servers that only listen on localhost. (CVE-2019-12523)

  - 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)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version
number.");
  # https://security.tuxcare.com/csaf/v2/els_os/centos6els/advisories/2026/clsa-2026_1777541147.json
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?3fc3d74c");
  script_set_attribute(attribute:"see_also", value:"https://cve.tuxcare.com/els/releases/CLSA-2026:1777541147");
  script_set_attribute(attribute:"solution", value:
"Update the affected squid34 package based on the guidance in TuxCare advisory CENTOS6:CLSA-2026:1777541147.");
  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:POC/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:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2019-12525");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");
  script_set_attribute(attribute:"vendor_severity", value:"Critical");

  script_set_attribute(attribute:"vuln_publication_date", value:"2018/01/23");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/04/30");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/10/01");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2026 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info2.nasl");
  script_require_keys("Host/OS/extended-third-party", "Host/local_checks_enabled", "Host/CentOS/release", "Host/CentOS/rpm-list");

  exit(0);
}
include('rpm2.inc');

var third_party_support = get_kb_item('Host/OS/extended-third-party');
if (empty_or_null(third_party_support) || third_party_support != 'TuxCare') exit(0, 'TuxCare support not enabled.');

if (!get_kb_item('Host/local_checks_enabled')) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var os_product = get_kb_item('installed_os/local/SSH/0/product');
if (isnull(os_product) || 'CentOS Linux' >!< os_product) audit(AUDIT_OS_NOT, 'CentOS Linux');
var os_version = get_kb_item('installed_os/local/SSH/0/version');
if (isnull(os_version)) audit(AUDIT_UNKNOWN_APP_VER, 'CentOS Linux');
if (! preg(pattern:"^6([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'CentOS Linux 6', 'CentOS Linux ' + os_version);

if (!get_kb_item('Host/CentOS/rpm-list')) audit(AUDIT_PACKAGE_LIST_MISSING);

var cpu = get_kb_item('Host/cpu');
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ('x86_64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'CentOS Linux', cpu);


var constraints = [
  {
    'release': '6',
    'pkgs': [
      {'reference':'squid34-3.4.14-16.el6.tuxcare.els13', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'7'}
    ]
  }
];

var os_release = get_one_kb_item('installed_os/local/SSH/0/release');
var os_sp = get_one_kb_item('Host/*/minor_release');

var flag = 0;
var reference;
var sp;
var _cpu;
var el_string;
var rpm_spec_vers_cmp;
var epoch;
var allowmaj;
var exists_check;
var cves;
foreach var constraint ( constraints ) {
  # Check that the target release is equal to the affected release
  if (!empty_or_null(constraint['release'])){
    if (constraint['release'] != os_release) continue;
  }
  if (!empty_or_null(constraint['sp'])){
    if (constraint['sp'] != os_sp) continue;
  }
  foreach var pkg ( constraint['pkgs'] ) {
    reference = NULL;
    sp = NULL;
    _cpu = NULL;
    el_string = NULL;
    rpm_spec_vers_cmp = NULL;
    epoch = NULL;
    allowmaj = NULL;
    exists_check = NULL;
    cves = NULL;
    if (!empty_or_null(pkg['reference'])) reference = pkg['reference'];
    if (!empty_or_null(pkg['sp'])) sp = pkg['sp'];
    if (!empty_or_null(pkg['cpu'])) _cpu = pkg['cpu'];
    if (!empty_or_null(pkg['el_string'])) el_string = pkg['el_string'];
    if (!empty_or_null(pkg['rpm_spec_vers_cmp'])) rpm_spec_vers_cmp = pkg['rpm_spec_vers_cmp'];
    if (!empty_or_null(pkg['epoch'])) epoch = pkg['epoch'];
    if (!empty_or_null(pkg['allowmaj'])) allowmaj = pkg['allowmaj'];
    if (!empty_or_null(pkg['exists_check'])) exists_check = pkg['exists_check'];
    if (!empty_or_null(pkg['cves'])) cves = pkg['cves'];
    if (reference &&
        ## (no known rpm to check OR known rpm_exists)
        (!exists_check || rpm_exists(rpm:exists_check)) &&
        rpm_check(sp:sp, cpu:_cpu, reference:reference, epoch:epoch, el_string:el_string, rpm_spec_vers_cmp:rpm_spec_vers_cmp, allowmaj:allowmaj, cves:cves)) flag++;
  }
}


if (flag)
{
  security_report_v4(
      port       : 0,
      severity   : SECURITY_HOLE,
      extra      : rpm_report_get()
  );
  exit(0);
}
else
{
  var tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'squid34');
}