Vulnerabilities > CVE-2016-7541 - 7PK - Security Features vulnerability in Fortinet Fortios

047910
CVSS 5.9 - MEDIUM
Attack vector
NETWORK
Attack complexity
HIGH
Privileges required
NONE
Confidentiality impact
NONE
Integrity impact
HIGH
Availability impact
NONE
network
high complexity
fortinet
CWE-254
nessus
NVD
Published: 2017-03-30
Updated: 2024-11-21

Summary

Long lived sessions in Fortinet FortiGate devices with FortiOS 5.x before 5.4.0 could violate a security policy during IPS signature updates when the FortiGate's IPSengine is configured in flow mode. All FortiGate versions with IPS configured in proxy mode (the default mode) are not affected.

Vulnerable Configurations

Part Description Count
OS
Fortinet
26

Common Weakness Enumeration (CWE)

Nessus

NASL familyFirewalls
NASL idFORTIOS_CVE-2016-7541.NASL
descriptionThe remote FortiGate device is running a version of FortiOS that is 5.x prior to 5.4.2. It is, therefore, affected by a security bypass vulnerability when reloading the scanning engine after an update that results in active network sessions no longer being monitored by flow-mode detection. An unauthenticated, remote attacker can exploit this vulnerability to bypass security protection.
last seen2020-06-01
modified2020-06-02
plugin id95439
published2016-12-01
reporterThis script is Copyright (C) 2016-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
sourcehttps://www.tenable.com/plugins/nessus/95439
titleFortinet FortiOS 5.x < 5.4.2 Flow-mode Detection Bypass
code
#
# (C) Tenable Network Security, Inc.
#

include("compat.inc");

if (description)
{
  script_id(95439);
  script_version("1.7");
  script_cvs_date("Date: 2019/11/13");

  script_cve_id("CVE-2016-7541");
  script_bugtraq_id(94477);

  script_name(english:"Fortinet FortiOS 5.x < 5.4.2 Flow-mode Detection Bypass");
  script_summary(english:"Checks the version of FortiOS.");

  script_set_attribute(attribute:"synopsis", value:
"The remote host is affected by a security bypass vulnerability.");
  script_set_attribute(attribute:"description", value:
"The remote FortiGate device is running a version of FortiOS that is
5.x prior to 5.4.2. It is, therefore, affected by a security bypass
vulnerability when reloading the scanning engine after an update that
results in active network sessions no longer being monitored by
flow-mode detection. An unauthenticated, remote attacker can exploit
this vulnerability to bypass security protection.");
  # http://fortiguard.com/advisory/fortios-flow-mode-detection-bypass-under-certain-conditions
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?79976042");
  script_set_attribute(attribute:"solution", value:
"Upgrade to Fortinet FortiOS version 5.4.2 or later.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:N/I:P/A:N");
  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:N/UI:N/S:U/C:N/I:H/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2016-7541");

  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:"2016/11/22");
  script_set_attribute(attribute:"patch_publication_date", value:"2016/11/22");
  script_set_attribute(attribute:"plugin_publication_date", value:"2016/12/01");

  script_set_attribute(attribute:"potential_vulnerability", value:"true");
  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:fortinet:fortios");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Firewalls");

  script_copyright(english:"This script is Copyright (C) 2016-2019 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("fortinet_version.nbin");
  script_require_keys("Host/Fortigate/model", "Host/Fortigate/version", "Settings/ParanoidReport");

  exit(0);
}

include("audit.inc");
include("global_settings.inc");
include("misc_func.inc");

if (report_paranoia < 2) audit(AUDIT_PARANOID);

app_name = "FortiOS";

version = get_kb_item_or_exit("Host/Fortigate/version");
model = get_kb_item_or_exit("Host/Fortigate/model");

# Make sure device is FortiGate
if (!preg(string:model, pattern:"fortigate", icase:TRUE)) audit(AUDIT_HOST_NOT, "a FortiGate");

if (version =~ "^5\.[024]\.") fix = "5.4.2";
else audit(AUDIT_INST_VER_NOT_VULN, app_name, version);

if (ver_compare(ver:version, fix:fix, strict:FALSE) == -1)
{
  report =
    '\n  Model             : ' + model +
    '\n  Installed version : ' + version +
    '\n  Fixed version     : ' + fix +
    '\n';
  security_report_v4(severity:SECURITY_WARNING, extra:report, port:0);
}
else audit(AUDIT_INST_VER_NOT_VULN, app_name, version);

References