QNAP QTS OpenSSH RCE Vulnerability (QSA-24-31, regreSSHion)

# 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:/o:qnap:qts";

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.114687");
  script_version("2024-07-04T05:05:37+0000");
  script_tag(name:"last_modification", value:"2024-07-04 05:05:37 +0000 (Thu, 04 Jul 2024)");
  script_tag(name:"creation_date", value:"2024-07-03 13:05:47 +0000 (Wed, 03 Jul 2024)");
  script_tag(name:"cvss_base", value:"10.0");
  script_tag(name:"cvss_base_vector", value:"AV:N/AC:L/Au:N/C:C/I:C/A:C");

  script_cve_id("CVE-2024-6387");

  # nb: Only a release candidate of 5.2.0 affected
  script_tag(name:"qod_type", value:"remote_banner_unreliable");

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

  script_name("QNAP QTS OpenSSH RCE Vulnerability (QSA-24-31, regreSSHion)");

  script_category(ACT_GATHER_INFO);

  script_copyright("Copyright (C) 2024 Greenbone AG");
  script_family("General");
  script_dependencies("gb_qnap_nas_http_detect.nasl");
  script_mandatory_keys("qnap/nas/qts/detected");

  script_tag(name:"summary", value:"QNAP QTS is prone to a remote code execution (RCE) vulnerability
  in OpenSSH dubbed 'regreSSHion'.");

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

  script_tag(name:"insight", value:"OpenSSH vendor insights:

  1) Race condition in sshd(8)

  A critical vulnerability in sshd(8) was present that may allow arbitrary code execution with root
  privileges.

  Successful exploitation has been demonstrated on 32-bit Linux/glibc systems with ASLR. Under lab
  conditions, the attack requires on average 6-8 hours of continuous connections up to the maximum
  the server will accept. Exploitation on 64-bit systems is believed to be possible but has not been
  demonstrated at this time. It's likely that these attacks will be improved upon.

  Exploitation on non-glibc systems is conceivable but has not been examined. Systems that lack ASLR
  or users of downstream Linux distributions that have modified OpenSSH to disable per-connection
  ASLR re-randomisation (yes - this is a thing, no - we don't understand why) may potentially have
  an easier path to exploitation.");

  script_tag(name:"affected", value:"QNAP QTS version 5.2.0 Release Candidate (RC).");

  script_tag(name:"solution", value:"Update to the final version 5.2.0 or later.");

  script_xref(name:"URL", value:"https://www.qnap.com/en/security-advisory/qsa-24-31");
  script_xref(name:"URL", value:"https://www.openssh.com/txt/release-9.8");
  script_xref(name:"URL", value:"https://www.openssh.com/security.html");
  script_xref(name:"URL", value:"https://www.qualys.com/2024/07/01/cve-2024-6387/regresshion.txt");
  script_xref(name:"URL", value:"https://www.qualys.com/regresshion-cve-2024-6387/");
  script_xref(name:"URL", value:"https://blog.qualys.com/vulnerabilities-threat-research/2024/07/01/regresshion-remote-unauthenticated-code-execution-vulnerability-in-openssh-server");
  script_xref(name:"URL", value:"https://unit42.paloaltonetworks.com/threat-brief-cve-2024-6387-openssh/");

  exit(0);
}

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

if (!version = get_app_version(cpe: CPE, nofork: TRUE))
  exit(0);

if (version =~ "^5\.2\.0") {
  report = report_fixed_ver(installed_version: version, fixed_version: "5.2.0 (Final version)");
  security_message(port: 0, data: report);
  exit(0);
}

exit(99);