Vulnerabilities > CVE-2019-1901 - Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability in Cisco Nx-Os

047910
CVSS 8.8 - HIGH
Attack vector
ADJACENT_NETWORK
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
HIGH
Integrity impact
HIGH
Availability impact
HIGH
low complexity
cisco
CWE-119
nessus

Summary

A vulnerability in the Link Layer Discovery Protocol (LLDP) subsystem of Cisco Nexus 9000 Series Application Centric Infrastructure (ACI) Mode Switch Software could allow an adjacent, unauthenticated attacker to cause a denial of service (DoS) condition or execute arbitrary code with root privileges. The vulnerability is due to improper input validation of certain type, length, value (TLV) fields of the LLDP frame header. An attacker could exploit this vulnerability by sending a crafted LLDP packet to the targeted device. A successful exploit may lead to a buffer overflow condition that could either cause a DoS condition or allow the attacker to execute arbitrary code with root privileges. Note: This vulnerability cannot be exploited by transit traffic through the device; the crafted packet must be targeted to a directly connected interface. This vulnerability affects Cisco Nexus 9000 Series Fabric Switches in ACI mode if they are running a Cisco Nexus 9000 Series ACI Mode Switch Software release prior to 13.2(7f) or any 14.x release.

Vulnerable Configurations

Part Description Count
OS
Cisco
866
Hardware
Cisco
23

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Buffer Overflow via Environment Variables
    This attack pattern involves causing a buffer overflow through manipulation of environment variables. Once the attacker finds that they can modify an environment variable, they may try to overflow associated buffers. This attack leverages implicit trust often placed in environment variables.
  • Overflow Buffers
    Buffer Overflow attacks target improper or missing bounds checking on buffer operations, typically triggered by input injected by an attacker. As a consequence, an attacker is able to write past the boundaries of allocated buffer regions in memory, causing a program crash or potentially redirection of execution as per the attackers' choice.
  • Client-side Injection-induced Buffer Overflow
    This type of attack exploits a buffer overflow vulnerability in targeted client software through injection of malicious content from a custom-built hostile service.
  • Filter Failure through Buffer Overflow
    In this attack, the idea is to cause an active filter to fail by causing an oversized transaction. An attacker may try to feed overly long input strings to the program in an attempt to overwhelm the filter (by causing a buffer overflow) and hoping that the filter does not fail securely (i.e. the user input is let into the system unfiltered).
  • MIME Conversion
    An attacker exploits a weakness in the MIME conversion routine to cause a buffer overflow and gain control over the mail server machine. The MIME system is designed to allow various different information formats to be interpreted and sent via e-mail. Attack points exist when data are converted to MIME compatible format and back.

Nessus

NASL familyCISCO
NASL idCISCO-SA-20190731-NXOS-BO.NASL
descriptionAccording to its self-reported version, the Cisco NX-OS Software in ACI mode is affected by a buffer overflow vulnerability. An unauthenticated, adjacent attacker could exploit this vulnerability, via a specially crafted Link Layer Discovery Protocol (LLDP) packet, to cause a denial-of-service condition or potentially execute arbitrary code with root privileges. Please see the reference Cisco BID and Cisco Security Advisory for more information.
last seen2020-06-01
modified2020-06-02
plugin id128532
published2019-09-06
reporterThis script is Copyright (C) 2019 and is owned by Tenable, Inc. or an Affiliate thereof.
sourcehttps://www.tenable.com/plugins/nessus/128532
titleCisco Nexus 9000 Series Fabric Switches ACI Mode Link Layer Discovery Protocol Buffer Overflow Vulnerability
code
#TRUSTED 961860857b35c5ad2f833310453c69c9808338a6be083832314566de23d55c09e58ca4d234b1b3c6caea4bc3ebdf1f6b4d4ad9e2354f9c9b50bc969d81ceb76257057a6dc9d57e8f19ed9da4148ea5c949c9cc2f16709087281c3bf4f39d1aa51f11e9d94e5800bf7699d7dcb00db54b49196cd19b62a624d9098f19c4944f395eed4c6636b3fddf21d6b58ec422dcbfa795f3285a6a1f1440fa325bc05a063a2ab3309098cc4fe6f46f193e0b91d53d46cad75cb86a5b342e871a94142657ae9046aafed586fb1b219e53abe408cd431c706146d9b2edc8a4ccbd6e6753a463ffbb3fc8e12280824e9331ccd82117a2e0a8559894cc0503f9f3eaba8f24370ded1d2cc502a571611cd03810dca2cf8d01aa35b16086751e7ab8544525e9181ecf70a79c9114f1e0844e6a597fc90c1cdf8ff7066d74936b1fb400c1c8fae5689adca779cb019caf200a4de9ab686c8ec4ec84c71c7746644590b6cc9847c57e9daf79321fbf54e694cc78e719881d60f35e9334698c822b00c6a4ca625902bea4ef78dbf2bc166e8929bd30ec60b914a84d90fb92ec9d229cad25b8769604ab1ef025aea38804f5b0c9281a0ec9b3ab76ef1e760bbe01d6457ab2e8155e8370799d9732a51182fe92994b2001856049eca7208de73ff37cf71964e59a707fb2f7d09f38d29399dca9f15f14eb31e7ab0e2183ef9ca63d29d0dcd2ca173bf4af
#
# (C) Tenable Network Security, Inc.
#

include("compat.inc");

if (description)
{
  script_id(128532);
  script_version("1.6");
  script_cvs_date("Date: 2019/12/20");

  script_cve_id("CVE-2019-1901");
  script_xref(name:"CISCO-BUG-ID", value:"CSCvp92121");
  script_xref(name:"CISCO-SA", value:"cisco-sa-20190731-nxos-bo");
  script_xref(name:"IAVA", value:"2019-A-0317");

  script_name(english:"Cisco Nexus 9000 Series Fabric Switches ACI Mode Link Layer Discovery Protocol Buffer Overflow Vulnerability");
  script_summary(english:"Checks the version of Cisco NX-OS System Software in ACI Mode");

  script_set_attribute(attribute:"synopsis", value:
"The remote device is missing a vendor-supplied security patch");
  script_set_attribute(attribute:"description", value:
"According to its self-reported version, the Cisco NX-OS Software in
ACI mode is affected by a buffer overflow vulnerability. An
unauthenticated, adjacent attacker could exploit this vulnerability,
via a specially crafted Link Layer Discovery Protocol (LLDP) packet,
to cause a denial-of-service condition or potentially execute arbitrary
code with root privileges. Please see the reference Cisco BID and Cisco
Security Advisory for more information.");
  # https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190731-nxos-bo
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?dd3ed165");
  script_set_attribute(attribute:"see_also", value:"https://bst.cloudapps.cisco.com/bugsearch/bug/CSCvp92121");
  script_set_attribute(attribute:"solution", value:
"Upgrade to the relevant fixed version referenced in Cisco bug ID CSCvp92121");
  script_set_cvss_base_vector("CVSS2#AV:A/AC:L/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:A/AC:L/PR:N/UI:N/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-2019-1901");
  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");


  script_set_attribute(attribute:"vuln_publication_date", value:"2019/07/31");
  script_set_attribute(attribute:"patch_publication_date", value:"2019/07/31");
  script_set_attribute(attribute:"plugin_publication_date", value:"2019/09/06");

  script_set_attribute(attribute:"potential_vulnerability", value:"true");
  script_set_attribute(attribute:"plugin_type", value:"combined");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:cisco:nx-os");
  script_set_attribute(attribute:"stig_severity", value:"I");
  script_end_attributes();

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

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

  script_dependencies("cisco_nxos_version.nasl");
  script_require_keys("Host/Cisco/NX-OS/Version", "Host/Cisco/NX-OS/Model", "Host/Cisco/NX-OS/Device", "Settings/ParanoidReport");

  exit(0);
}

include('audit.inc');
include('cisco_workarounds.inc');
include('ccf.inc');

if (report_paranoia < 2) audit(AUDIT_PARANOID);

product_info = cisco::get_product_info(name:'Cisco NX-OS Software');

if ('Nexus' >!< product_info['device'] || product_info['model'] !~ '^90[0-9][0-9]')
  audit(AUDIT_HOST_NOT, 'affected');

version_list=make_list(
  '14.1.2g',
  '14.1.1l',
  '14.1.1k',
  '14.1.1j',
  '14.1.1i',
  '14.0.3d',
  '14.0.2c',
  '14.0.1h',
  '13.2.6i',
  '13.2.5f',
  '13.2.5e',
  '13.2.5d',
  '13.2.4e',
  '13.2.4d',
  '13.2.3s',
  '13.2.3r',
  '13.2.3o',
  '13.2.3n',
  '13.2.3j',
  '13.2.3i',
  '13.2.2o',
  '13.2.2l',
  '13.2.1m',
  '13.2.1l',
  '13.1.2u',
  '13.1.2t',
  '13.1.2s',
  '13.1.2q',
  '13.1.2p',
  '13.1.2o',
  '13.1.2m',
  '13.1.1i',
  '13.0.2n',
  '13.0.2k',
  '13.0.2h',
  '13.0.1k',
  '12.3.1p',
  '12.3.1o',
  '12.3.1l',
  '12.3.1i',
  '12.3.1f',
  '12.3.1e',
  '12.2.4r',
  '12.2.4q',
  '12.2.4p',
  '12.2.4f',
  '12.2.3t',
  '12.2.3s',
  '12.2.3r',
  '12.2.3p',
  '12.2.3j',
  '12.2.2q',
  '12.2.2k',
  '12.2.2j',
  '12.2.2i',
  '12.2.2g',
  '12.2.2f',
  '12.2.2e',
  '12.2.1o',
  '12.2.1n',
  '12.1.4a',
  '12.1.3j',
  '12.1.3h',
  '12.1.3g',
  '12.1.2k',
  '12.1.2g',
  '12.1.2e',
  '12.1.1i',
  '12.1.1h',
  '12.0.2o',
  '12.0.2n',
  '12.0.2m',
  '12.0.2l',
  '12.0.2h',
  '12.0.2g',
  '12.0.2f',
  '12.0.1r',
  '12.0.1q',
  '12.0.1p',
  '12.0.1o',
  '12.0.1n',
  '12.0.1m',
  '11.3.2k',
  '11.3.2j',
  '11.3.2i',
  '11.3.2h',
  '11.3.2f',
  '11.3.1j',
  '11.3.1i',
  '11.3.1h',
  '11.3.1g',
  '11.2.3m',
  '11.2.3h',
  '11.2.3e',
  '11.2.3c',
  '11.2.2j',
  '11.2.2i',
  '11.2.2h',
  '11.2.2g',
  '11.2.1m',
  '11.2.1k',
  '11.2.1i',
  '11.1.4m',
  '11.1.4l',
  '11.1.4i',
  '11.1.4g',
  '11.1.4f',
  '11.1.4e',
  '11.1.4',
  '11.1.3f',
  '11.1.2i',
  '11.1.2h',
  '11.1.1s',
  '11.1.1r',
  '11.1.1o',
  '11.1.1j',
  '11.0.4q',
  '11.0.4o',
  '11.0.4h',
  '11.0.3o',
  '11.0.3n',
  '11.0.3k',
  '11.0.3i',
  '11.0.3f',
  '11.0.2m',
  '11.0.2j',
  '11.0.1e',
  '11.0.1d',
  '11.0.1c',
  '11.0.1b'
);

workarounds = make_list(CISCO_WORKAROUNDS['no_workaround']);
workaround_params = make_list();


reporting = make_array(
'port'     , 0,
'severity' , SECURITY_HOLE,
'version'  , product_info['version'],
'bug_id'   , 'CSCvp92121'
);

cisco::check_and_report(product_info:product_info, workarounds:workarounds, workaround_params:workaround_params, reporting:reporting, vuln_versions:version_list);