CVSS2
Attack Vector
NETWORK
Attack Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
PARTIAL
AV:N/AC:M/Au:N/C:N/I:N/A:P
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS
Percentile
52.6%
A vulnerability within the Endpoint Learning feature of Cisco Nexus 9000 Series Switches running in Application Centric Infrastructure (ACI) mode could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an endpoint device in certain circumstances. The vulnerability is due to improper endpoint learning when packets are received on a specific port from outside the ACI fabric and destined to an endpoint located on a border leaf when Disable Remote Endpoint Learning has been enabled. This can result in a Remote (XR) entry being created for the impacted endpoint that will become stale if the endpoint migrates to a different port or leaf switch. This results in traffic not reaching the impacted endpoint until the Remote entry can be relearned by another mechanism.
This plugin only works with Tenable.ot.
Please visit https://www.tenable.com/products/tenable-ot for more information.
#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
##
include('compat.inc');
if (description)
{
script_id(501402);
script_version("1.1");
script_set_attribute(attribute:"plugin_modification_date", value:"2023/07/26");
script_cve_id("CVE-2019-1977");
script_name(english:"Cisco Nexus 9000 Series Fabric Switches ACI Mode Border Leaf Endpoint Learning (CVE-2019-1977)");
script_set_attribute(attribute:"synopsis", value:
"The remote OT asset is affected by a vulnerability.");
script_set_attribute(attribute:"description", value:
"A vulnerability within the Endpoint Learning feature of Cisco Nexus
9000 Series Switches running in Application Centric Infrastructure
(ACI) mode could allow an unauthenticated, remote attacker to cause a
denial of service (DoS) condition on an endpoint device in certain
circumstances. The vulnerability is due to improper endpoint learning
when packets are received on a specific port from outside the ACI
fabric and destined to an endpoint located on a border leaf when
Disable Remote Endpoint Learning has been enabled. This can result in
a Remote (XR) entry being created for the impacted endpoint that will
become stale if the endpoint migrates to a different port or leaf
switch. This results in traffic not reaching the impacted endpoint
until the Remote entry can be relearned by another mechanism.
This plugin only works with Tenable.ot.
Please visit https://www.tenable.com/products/tenable-ot for more information.");
# https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190828-nexus-aci-dos
script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?9a5ce967");
script_set_attribute(attribute:"solution", value:
"Refer to the vendor advisory.");
script_set_cvss_base_vector("CVSS2#AV:N/AC:M/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-2019-1977");
script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
script_cwe_id(371);
script_set_attribute(attribute:"vuln_publication_date", value:"2019/08/30");
script_set_attribute(attribute:"patch_publication_date", value:"2019/08/30");
script_set_attribute(attribute:"plugin_publication_date", value:"2023/07/25");
script_set_attribute(attribute:"plugin_type", value:"remote");
script_set_attribute(attribute:"cpe", value:"cpe:/o:cisco:nx-os:12.3%281h%29");
script_set_attribute(attribute:"cpe", value:"cpe:/o:cisco:nx-os:13.1%282m%29");
script_set_attribute(attribute:"cpe", value:"cpe:/o:cisco:nx-os:13.1%282o%29");
script_set_attribute(attribute:"cpe", value:"cpe:/o:cisco:nx-os:13.1%282p%29");
script_set_attribute(attribute:"generated_plugin", value:"former");
script_end_attributes();
script_category(ACT_GATHER_INFO);
script_family(english:"Tenable.ot");
script_copyright(english:"This script is Copyright (C) 2023 and is owned by Tenable, Inc. or an Affiliate thereof.");
script_dependencies("tenable_ot_api_integration.nasl");
script_require_keys("Tenable.ot/Cisco");
exit(0);
}
include('tenable_ot_cve_funcs.inc');
get_kb_item_or_exit('Tenable.ot/Cisco');
var asset = tenable_ot::assets::get(vendor:'Cisco');
var vuln_cpes = {
"cpe:/o:cisco:nx-os:12.3%281h%29" :
{"versionEndIncluding" : "12.3%281h%29", "versionStartIncluding" : "12.3%281h%29", "family" : "NXOS"},
"cpe:/o:cisco:nx-os:13.1%282m%29" :
{"versionEndIncluding" : "13.1%282m%29", "versionStartIncluding" : "13.1%282m%29", "family" : "NXOS"},
"cpe:/o:cisco:nx-os:13.1%282o%29" :
{"versionEndIncluding" : "13.1%282o%29", "versionStartIncluding" : "13.1%282o%29", "family" : "NXOS"},
"cpe:/o:cisco:nx-os:13.1%282p%29" :
{"versionEndIncluding" : "13.1%282p%29", "versionStartIncluding" : "13.1%282p%29", "family" : "NXOS"}
};
tenable_ot::cve::compare_and_report(asset:asset, cpes:vuln_cpes, severity:SECURITY_WARNING);
CVSS2
Attack Vector
NETWORK
Attack Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
PARTIAL
AV:N/AC:M/Au:N/C:N/I:N/A:P
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS
Percentile
52.6%