According to its banner, the version of OpenSSL running on the remote host is 1.1.0 prior to 1.1.0e. It is, therefore, affected by a denial of service vulnerability that is triggered during a renegotiation handshake in which the Encrypt-Then-Mac extension is negotiated when it was not in the original handshake or vice-versa. An unauthenticated, remote attacker can exploit this issue to cause OpenSSL to crash, depending on which cipher suite is being used. Note that both clients and servers are affected.
#
# (C) Tenable Network Security, Inc.
#
include("compat.inc");
if (description)
{
script_id(97328);
script_version("1.7");
script_set_attribute(attribute:"plugin_modification_date", value:"2023/08/08");
script_cve_id("CVE-2017-3733");
script_name(english:"OpenSSL 1.1.0 < 1.1.0e Encrypt-Then-Mac Extension DoS");
script_summary(english:"Performs a banner check.");
script_set_attribute(attribute:"synopsis", value:
"A service running on the remote host is affected by a denial of
service vulnerability.");
script_set_attribute(attribute:"description", value:
"According to its banner, the version of OpenSSL running on the remote
host is 1.1.0 prior to 1.1.0e. It is, therefore, affected by a denial
of service vulnerability that is triggered during a renegotiation
handshake in which the Encrypt-Then-Mac extension is negotiated when
it was not in the original handshake or vice-versa. An
unauthenticated, remote attacker can exploit this issue to cause
OpenSSL to crash, depending on which cipher suite is being used. Note
that both clients and servers are affected.");
script_set_attribute(attribute:"see_also", value:"https://www.openssl.org/news/secadv/20170216.txt");
script_set_attribute(attribute:"solution", value:
"Upgrade to OpenSSL version 1.1.0e or later.");
script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/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:L/PR:N/UI:N/S:U/C:N/I:N/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-2017-3733");
script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
script_set_attribute(attribute:"exploit_available", value:"false");
script_set_attribute(attribute:"vuln_publication_date", value:"2017/02/16");
script_set_attribute(attribute:"patch_publication_date", value:"2017/02/16");
script_set_attribute(attribute:"plugin_publication_date", value:"2017/02/23");
script_set_attribute(attribute:"plugin_type", value:"combined");
script_set_attribute(attribute:"cpe", value:"cpe:/a:openssl:openssl");
script_set_attribute(attribute:"agent", value:"all");
script_end_attributes();
script_category(ACT_GATHER_INFO);
script_family(english:"Web Servers");
script_copyright(english:"This script is Copyright (C) 2017-2023 and is owned by Tenable, Inc. or an Affiliate thereof.");
script_dependencies("openssl_version.nasl", "openssl_nix_installed.nbin", "openssl_win_installed.nbin");
script_require_keys("installed_sw/OpenSSL");
exit(0);
}
include('vcf.inc');
include('vcf_extras_openssl.inc');
var app_info = vcf::combined_get_app_info(app:'OpenSSL');
vcf::check_all_backporting(app_info:app_info);
var constraints = [{ 'min_version' : "1.1.0", 'fixed_version' : '1.1.0e'}];
vcf::openssl::check_version_and_report(app_info:app_info, constraints:constraints, severity:SECURITY_WARNING);