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nessusThis script is Copyright (C) 2023 and is owned by Tenable, Inc. or an Affiliate thereof.FEDORA_2023-1176C8B10C.NASL
HistoryApr 18, 2023 - 12:00 a.m.

Fedora 37 : openssh (2023-1176c8b10c)

2023-04-1800:00:00
This script is Copyright (C) 2023 and is owned by Tenable, Inc. or an Affiliate thereof.
www.tenable.com
46
fedora 37
openssh server
vulnerability
double-free
remote attacker
code execution
cve-2023-25136
nessus scanner

0.009 Low

EPSS

Percentile

82.6%

The remote Fedora 37 host has a package installed that is affected by a vulnerability as referenced in the FEDORA-2023-1176c8b10c advisory.

  • OpenSSH server (sshd) 9.1 introduced a double-free vulnerability during options.kex_algorithms handling.
    This is fixed in OpenSSH 9.2. The double free can be leveraged, by an unauthenticated remote attacker in the default configuration, to jump to any location in the sshd address space. One third-party report states remote code execution is theoretically possible. (CVE-2023-25136)

Note that Nessus has not tested for this issue but has instead relied only on the application’s self-reported version number.

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
##
# The descriptive text and package checks in this plugin were
# extracted from Fedora Security Advisory FEDORA-2023-1176c8b10c
#

include('compat.inc');

if (description)
{
  script_id(174424);
  script_version("1.0");
  script_set_attribute(attribute:"plugin_modification_date", value:"2023/04/18");

  script_cve_id("CVE-2023-25136");
  script_xref(name:"IAVA", value:"2023-A-0073-S");
  script_xref(name:"FEDORA", value:"2023-1176c8b10c");

  script_name(english:"Fedora 37 : openssh (2023-1176c8b10c)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Fedora host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The remote Fedora 37 host has a package installed that is affected by a vulnerability as referenced in the
FEDORA-2023-1176c8b10c advisory.

  - OpenSSH server (sshd) 9.1 introduced a double-free vulnerability during options.kex_algorithms handling.
    This is fixed in OpenSSH 9.2. The double free can be leveraged, by an unauthenticated remote attacker in
    the default configuration, to jump to any location in the sshd address space. One third-party report
    states remote code execution is theoretically possible. (CVE-2023-25136)

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://bodhi.fedoraproject.org/updates/FEDORA-2023-1176c8b10c");
  script_set_attribute(attribute:"solution", value:
"Update the affected openssh package.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:H/Au:N/C:N/I:P/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:POC/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/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-2023-25136");

  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:"2023/02/03");
  script_set_attribute(attribute:"patch_publication_date", value:"2023/04/14");
  script_set_attribute(attribute:"plugin_publication_date", value:"2023/04/18");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:fedoraproject:fedora:37");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fedoraproject:fedora:openssh");
  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:"Fedora Local Security Checks");

  script_copyright(english:"This script is Copyright (C) 2023 and is owned by Tenable, Inc. or an Affiliate thereof.");

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

  exit(0);
}


include('rpm.inc');

if (!get_kb_item('Host/local_checks_enabled')) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var os_release = get_kb_item('Host/RedHat/release');
if (isnull(os_release) || 'Fedora' >!< os_release) audit(AUDIT_OS_NOT, 'Fedora');
var os_ver = pregmatch(pattern: "Fedora.*release ([0-9]+)", string:os_release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, 'Fedora');
os_ver = os_ver[1];
if (! preg(pattern:"^37([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, 'Fedora 37', 'Fedora ' + os_ver);

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

var pkgs = [
    {'reference':'openssh-8.8p1-10.fc37', 'release':'FC37', 'rpm_spec_vers_cmp':TRUE, 'allowmaj':TRUE}
];

var flag = 0;
foreach package_array ( pkgs ) {
  var reference = NULL;
  var _release = NULL;
  var sp = NULL;
  var _cpu = NULL;
  var el_string = NULL;
  var rpm_spec_vers_cmp = NULL;
  var epoch = NULL;
  var allowmaj = NULL;
  if (!empty_or_null(package_array['reference'])) reference = package_array['reference'];
  if (!empty_or_null(package_array['release'])) _release = 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 (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, 'openssh');
}
VendorProductVersionCPE
fedoraprojectfedora37cpe:/o:fedoraproject:fedora:37
fedoraprojectfedoraopensshp-cpe:/a:fedoraproject:fedora:openssh