OpenSSH 8.2 < 8.5

##
# (C) Tenable, Inc.
##

include('compat.inc');

if (description)
{
  script_id(147662);
  script_version("1.8");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/03/27");

  script_cve_id("CVE-2021-28041");
  script_xref(name:"IAVA", value:"2021-A-0121-S");

  script_name(english:"OpenSSH 8.2 < 8.5");

  script_set_attribute(attribute:"synopsis", value:
"The SSH server running on the remote host is affected by a double-free error.");
  script_set_attribute(attribute:"description", value:
"ssh-agent in OpenSSH 8.2 < 8.5 has a double free that may be relevant in a few less-common scenarios, such as
unconstrained agent-socket access on a legacy operating system, or the forwarding of an agent to an attacker-controlled
host.

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://www.openwall.com/lists/oss-security/2021/03/03/1");
  script_set_attribute(attribute:"see_also", value:"https://www.openssh.com/txt/release-8.5");
  script_set_attribute(attribute:"solution", value:
"Upgrade to OpenSSH version 8.5 or later.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:H/Au:S/C:P/I:P/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/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-2021-28041");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");

  script_set_attribute(attribute:"vuln_publication_date", value:"2021/03/03");
  script_set_attribute(attribute:"patch_publication_date", value:"2021/03/03");
  script_set_attribute(attribute:"plugin_publication_date", value:"2021/03/11");

  script_set_attribute(attribute:"potential_vulnerability", value:"true");
  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:openbsd:openssh");
  script_set_attribute(attribute:"stig_severity", value:"I");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Misc.");

  script_copyright(english:"This script is Copyright (C) 2023-2024 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("openssh_detect.nbin");
  script_require_keys("installed_sw/OpenSSH", "Settings/ParanoidReport");
  script_require_ports("Services/ssh", 22);

  exit(0);
}

include('backport.inc');
include('vcf.inc');
include('vcf_extras.inc');

var port = get_service(svc:'ssh', default:22, exit_on_fail:TRUE);
var app_info = vcf::openssh::get_app_info(app:'OpenSSH', port:port);

# uncertain exploitation conditions
if (report_paranoia < 2) audit(AUDIT_PARANOID);

vcf::check_all_backporting(app_info:app_info);

var constraints = [
  {'min_version': '8.2', 'fixed_version': '8.5'}
];

vcf::openssh::check_version_and_report(app_info:app_info, constraints:constraints, severity:SECURITY_WARNING);