Alibaba Cloud Linux 3 : 0020: pcs (ALINUX3-SA-2026:0020)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The package checks in this plugin were extracted from
# Alibaba Cloud Linux Security Advisory ALINUX3-SA-2026:0020.
##

include('compat.inc');

if (description)
{
  script_id(297530);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/02/02");

  script_cve_id("CVE-2025-67725", "CVE-2025-67726");

  script_name(english:"Alibaba Cloud Linux 3 : 0020: pcs  (ALINUX3-SA-2026:0020)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Alibaba Cloud Linux host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The remote Alibaba Cloud Linux 3 host has packages installed that are affected by multiple vulnerabilities as referenced
in the ALINUX3-SA-2026:0020 advisory.

    Package updates are available for Alibaba Cloud Linux 3 that fix the following vulnerabilities:

    CVE-2025-67725:
    Tornado is a Python web framework and asynchronous networking library. In versions 6.5.2 and below, a
    single maliciously crafted HTTP request can block the server's event loop for an extended period, caused
    by the HTTPHeaders.add method. The function accumulates values using string concatenation when the same
    header name is repeated, causing a Denial of Service (DoS).  Due to Python string immutability, each
    concatenation copies the entire string, resulting in O(n) time complexity. The severity can vary from
    high if max_header_size has been increased from its default, to low if it has its default value of 64KB.
    This issue is fixed in version 6.5.3.

    CVE-2025-67726:
    Tornado is a Python web framework and asynchronous networking library. Versions 6.5.2 and below use an
    inefficient algorithm when parsing parameters for HTTP header values, potentially causing a DoS. The
    _parseparam function in httputil.py is used to parse specific HTTP header values, such as those in
    multipart/form-data and repeatedly calls string.count() within a nested loop while processing quoted
    semicolons. If an attacker sends a request with a large number of maliciously crafted parameters in a
    Content-Disposition header, the server's CPU usage increases quadratically (O(n)) during parsing. Due to
    Tornado's single event loop architecture, a single malicious request can cause the entire server to become
    unresponsive for an extended period. This issue is fixed in version 6.5.3.

Tenable has extracted the preceding description block directly from the Alibaba Cloud Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version
number.");
  script_set_attribute(attribute:"see_also", value:"http://mirrors.aliyun.com/alinux/3/cve/alinux3-sa-20260020.xml");
  script_set_attribute(attribute:"solution", value:
"Update the affected pcs and / or pcs-snmp packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C");
  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:N/I:N/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-2025-67726");

  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:"2025/12/12");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/01/30");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/02/02");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:pcs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:pcs-snmp");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:alibabacloud:alibaba_cloud_linux_3");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Alibaba Cloud Linux 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_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/Alibaba/release", "Host/Alibaba/rpm-list", "Host/cpu");

  exit(0);
}


include('rpm2.inc');

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) || 'Alibaba Cloud Linux' >!< os_product) audit(AUDIT_OS_NOT, 'Alibaba Cloud Linux');
var os_version = get_kb_item('installed_os/local/SSH/0/version');
if (isnull(os_version)) audit(AUDIT_UNKNOWN_APP_VER, 'Alibaba Cloud Linux');
if (! preg(pattern:"^3([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'Alibaba Cloud Linux 3.x', 'Alibaba Cloud Linux ' + os_version);

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

var cpu = get_kb_item('Host/cpu');
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ('aarch64' >!< cpu && 'x86_64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Alibaba Cloud Linux', cpu);

var constraints = [
  {
    'release': '3',
    'pkgs': [
      {'reference':'pcs-0.10.18-2.0.1.1.al8.8', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'pcs-0.10.18-2.0.1.1.al8.8', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'pcs-snmp-0.10.18-2.0.1.1.al8.8', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'pcs-snmp-0.10.18-2.0.1.1.al8.8', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'}
    ]
  }
];

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, 'pcs / pcs-snmp');
}