OpenBSD OpenSSH <= 9.6 Authentication Bypass Vulnerability

# SPDX-FileCopyrightText: 2024 Greenbone AG
# Some text descriptions might be excerpted from (a) referenced
# source(s), and are Copyright (C) by the respective right holder(s).
#
# SPDX-License-Identifier: GPL-2.0-only

CPE = "cpe:/a:openbsd:openssh";

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.114398");
  script_version("2024-06-27T05:05:29+0000");
  script_tag(name:"last_modification", value:"2024-06-27 05:05:29 +0000 (Thu, 27 Jun 2024)");
  script_tag(name:"creation_date", value:"2024-02-29 08:02:29 +0000 (Thu, 29 Feb 2024)");
  script_tag(name:"cvss_base", value:"6.0");
  script_tag(name:"cvss_base_vector", value:"AV:L/AC:H/Au:S/C:C/I:C/A:C");
  script_tag(name:"severity_vector", value:"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H");
  script_tag(name:"severity_origin", value:"NVD");
  script_tag(name:"severity_date", value:"2024-01-04 19:18:14 +0000 (Thu, 04 Jan 2024)");

  script_cve_id("CVE-2023-51767");

  script_tag(name:"qod_type", value:"remote_banner_unreliable");

  script_tag(name:"solution_type", value:"NoneAvailable");

  script_name("OpenBSD OpenSSH <= 9.6 Authentication Bypass Vulnerability");

  script_category(ACT_GATHER_INFO);

  script_copyright("Copyright (C) 2024 Greenbone AG");
  script_family("General");
  script_dependencies("gb_openssh_consolidation.nasl");
  script_mandatory_keys("openssh/detected");

  script_tag(name:"summary", value:"OpenBSD OpenSSH is prone to an authentication bypass
  vulnerability.");

  script_tag(name:"vuldetect", value:"Checks if a vulnerable version is present on the target host.");

  script_tag(name:"insight", value:"When common types of DRAM are used, OpenSSH might allow row
  hammer attacks (for authentication bypass) because the integer value of authenticated in
  mm_answer_authpassword does not resist flips of a single bit.

  NOTE: this is applicable to a certain threat model of attacker-victim co-location in which the
  attacker has user privileges.");

  script_tag(name:"affected", value:"OpenBSD OpenSSH version 9.6 and prior.");

  script_tag(name:"solution", value:"No known solution is available as of 26th June, 2024.
  Information regarding this issue will be updated once solution details are available.");

  script_xref(name:"URL", value:"https://access.redhat.com/security/cve/CVE-2023-51767");
  script_xref(name:"URL", value:"https://bugzilla.redhat.com/show_bug.cgi?id=2255850");
  script_xref(name:"URL", value:"https://arxiv.org/abs/2309.02545");

  exit(0);
}

include("version_func.inc");
include("host_details.inc");

if (isnull(port = get_app_port(cpe: CPE)))
  exit(0);

if (!infos = get_app_version_and_location(cpe: CPE, port: port, exit_no_version: TRUE))
  exit(0);

version = infos["version"];
location = infos["location"];

if (version_is_less_equal(version: version, test_version: "9.6")) {
  report = report_fixed_ver(installed_version: version, fixed_version: "None", install_path: location);
  security_message(port: port, data: report);
  exit(0);
}

exit(0);