TencentOS Server 3: dovecot (TSSA-2024:0516)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Tencent Linux Security Advisory TSSA-2024:0516.
##

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

if (description)
{
  script_id(239286);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2025/11/20");

  script_cve_id("CVE-2024-23184", "CVE-2024-23185");

  script_name(english:"TencentOS Server 3: dovecot (TSSA-2024:0516)");

  script_set_attribute(attribute:"synopsis", value:
"The remote TencentOS Server 3 host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The version of Tencent Linux installed on the remote TencentOS Server 3 host is prior to tested version. It is,
therefore, affected by multiple vulnerabilities as referenced in the TSSA-2024:0516 advisory.

    Package updates are available for TencentOS Server 3 that fix the following vulnerabilities:

    CVE-2024-23184:
    Having a large number of address headers (From, To, Cc, Bcc, etc.) becomes excessively CPU intensive. With
    100k header lines CPU usage is already 12 seconds, and in a production environment we observed 500k header
    lines taking 18 minutes to parse. Since this can be triggered by external actors sending emails to a
    victim, this is a security issue. An external attacker can send specially crafted messages that consume
    target system resources and cause outage. One can implement restrictions on address headers on MTA
    component preceding Dovecot. No publicly available exploits are known.

    CVE-2024-23185:
    Very large headers can cause resource exhaustion when parsing message. The message-parser normally reads
    reasonably sized chunks of the message. However, when it feeds them to message-header-parser, it starts
    building up full_value buffer out of the smaller chunks. The full_value buffer has no size limit, so
    large headers can cause large memory usage. It doesn't matter whether it's a single long header line, or a
    single header split into multiple lines. This bug exists in all Dovecot versions. Incoming mails typically
    have some size limits set by MTA, so even largest possible header size may still fit into Dovecot's
    vsz_limit. So attackers probably can't DoS a victim user this way. A user could APPEND larger mails
    though, allowing them to DoS themselves (although maybe cause some memory issues for the backend in
    general). One can implement restrictions on headers on MTA component preceding Dovecot. No publicly
    available exploits are known.

Tenable has extracted the preceding description block directly from the Tencent 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:"https://mirrors.tencent.com/tlinux/errata/tssa-20240516.xml");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:S/C:N/I:P/A:N");
  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:L/UI:N/S:C/C:N/I:L/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2024-23184");

  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:"2024/09/24");
  script_set_attribute(attribute:"patch_publication_date", value:"2024/09/24");
  script_set_attribute(attribute:"plugin_publication_date", value:"2025/06/16");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:tencent:tencentos_server:3");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:tencent:tencentos_server:dovecot");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2025 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info2.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/etc/os-release", "Host/TencentOS/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) || 'TencentOS' >!< os_product) audit(AUDIT_OS_NOT, 'TencentOS');
var os_version = get_kb_item('installed_os/local/SSH/0/version');
if (isnull(os_version)) audit(AUDIT_UNKNOWN_APP_VER, 'TencentOS');
if (! preg(pattern:"^3([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'TencentOS 3.x', 'TencentOS ' + os_version);

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

var constraints = [
  {
    'release': '3',
    'pkgs': [
      {'reference':'dovecot-2.3.16-6.tl3', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'dovecot-2.3.16-6.tl3', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'dovecot-debuginfo-2.3.16-6.tl3', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'dovecot-debuginfo-2.3.16-6.tl3', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'dovecot-debugsource-2.3.16-6.tl3', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'dovecot-debugsource-2.3.16-6.tl3', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'dovecot-devel-2.3.16-6.tl3', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'dovecot-devel-2.3.16-6.tl3', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'dovecot-mysql-2.3.16-6.tl3', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'dovecot-mysql-2.3.16-6.tl3', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'dovecot-mysql-debuginfo-2.3.16-6.tl3', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'dovecot-mysql-debuginfo-2.3.16-6.tl3', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'dovecot-pgsql-2.3.16-6.tl3', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'dovecot-pgsql-2.3.16-6.tl3', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'dovecot-pgsql-debuginfo-2.3.16-6.tl3', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'dovecot-pgsql-debuginfo-2.3.16-6.tl3', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'dovecot-pigeonhole-2.3.16-6.tl3', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'dovecot-pigeonhole-2.3.16-6.tl3', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'dovecot-pigeonhole-debuginfo-2.3.16-6.tl3', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'dovecot-pigeonhole-debuginfo-2.3.16-6.tl3', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE}
    ]
  }
];

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_WARNING,
      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, 'dovecot / dovecot-debuginfo / dovecot-debugsource / etc');
}