Vulnerabilities > CVE-2016-1453 - Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability in Cisco Nx-Os

047910
CVSS 10.0 - CRITICAL
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
COMPLETE
Integrity impact
COMPLETE
Availability impact
COMPLETE
network
low complexity
cisco
CWE-119
critical
nessus
NVD
Published: 2016-10-06
Updated: 2022-06-05

Summary

Buffer overflow in the Overlay Transport Virtualization (OTV) GRE feature in Cisco NX-OS 5.0 through 7.3 on Nexus 7000 and 7700 devices allows remote attackers to execute arbitrary code via long parameters in a packet header, aka Bug ID CSCuy95701.

Vulnerable Configurations

Part Description Count
OS
Cisco
46

Common Weakness Enumeration (CWE)

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-20161005-OTV-NXOS.NASL
descriptionAccording to its version and configuration, the Cisco NX-OS software running on the remote device is affected by a remote code execution vulnerability in the Overlay Transport Virtualization (OTV) generic routing encapsulation (GRE) feature due to improper validation of the size of OTV packet header parameters. An unauthenticated, remote attacker can exploit this, via long parameters in a packet header, to cause a denial of service condition or the execution of arbitrary code.
last seen2020-06-01
modified2020-06-02
plugin id94109
published2016-10-18
reporterThis script is Copyright (C) 2016-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
sourcehttps://www.tenable.com/plugins/nessus/94109
titleCisco NX-OS OTV GRE Packet Header Parameter Handling RCE (cisco-sa-20161005-otv)
code
#TRUSTED 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
#
# (C) Tenable Network Security, Inc.
#

include("compat.inc");

if (description)
{
  script_id(94109);
  script_version("1.10");
  script_cvs_date("Date: 2019/11/14");

  script_cve_id("CVE-2016-1453");
  script_bugtraq_id(93409);
  script_xref(name:"CISCO-BUG-ID", value:"CSCuy95701");
  script_xref(name:"CISCO-SA", value:"cisco-sa-20161005-otv");

  script_name(english:"Cisco NX-OS OTV GRE Packet Header Parameter Handling RCE (cisco-sa-20161005-otv)");
  script_summary(english:"Checks the NX-OS version.");

  script_set_attribute(attribute:"synopsis", value:
"The remote device is affected by a buffer overflow vulnerability.");
  script_set_attribute(attribute:"description", value:
"According to its version and configuration, the Cisco NX-OS software
running on the remote device is affected by a remote code execution
vulnerability in the Overlay Transport Virtualization (OTV) generic
routing encapsulation (GRE) feature due to improper validation of the
size of OTV packet header parameters. An unauthenticated, remote
attacker can exploit this, via long parameters in a packet header, to
cause a denial of service condition or the execution of arbitrary
code.");
  # https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20161005-otv
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?c3d6721f");
  script_set_attribute(attribute:"see_also", value:"https://bst.cloudapps.cisco.com/bugsearch/bug/CSCuy95701");
  script_set_attribute(attribute:"solution", value:
"Upgrade to the relevant fixed version referenced in Cisco advisory
cisco-sa-20161005-otv. Alternatively, as a workaround, configure an
Access Control List (ACL) to drop malformed OTV control packets.");
  script_set_cvss_base_vector("CVSS2#AV:N/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:N/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:"exploitability_ease", value:"No known exploits are available");

  script_set_attribute(attribute:"vuln_publication_date", value:"2016/10/05");
  script_set_attribute(attribute:"patch_publication_date", value:"2016/10/05");
  script_set_attribute(attribute:"plugin_publication_date", value:"2016/10/18");

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

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

  script_copyright(english:"This script is Copyright (C) 2016-2019 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/Device", "Host/Cisco/NX-OS/Model");

  exit(0);
}

include("audit.inc");
include("cisco_func.inc");
include("cisco_kb_cmd_func.inc");

device  = get_kb_item_or_exit("Host/Cisco/NX-OS/Device");
model   = get_kb_item_or_exit("Host/Cisco/NX-OS/Model");
if (device != 'Nexus' || (model !~ '^7[07]{1}[0-9][0-9]([^0-9]|$)'))
  audit(AUDIT_HOST_NOT, "Nexus model 7000 / 7700");

version = get_kb_item_or_exit("Host/Cisco/NX-OS/Version");
flag = FALSE;

if ( version == "4.1(2)" ) flag = TRUE;
if ( version == "4.1(3)" ) flag = TRUE;
if ( version == "4.1(4)" ) flag = TRUE;
if ( version == "4.1(5)" ) flag = TRUE;
if ( version == "4.2(2a)" ) flag = TRUE;
if ( version == "4.2(3)" ) flag = TRUE;
if ( version == "4.2(4)" ) flag = TRUE;
if ( version == "4.2(6)" ) flag = TRUE;
if ( version == "4.2(8)" ) flag = TRUE;
if ( version == "5.0(2a)" ) flag = TRUE;
if ( version == "5.0(3)" ) flag = TRUE;
if ( version == "5.0(5)" ) flag = TRUE;
if ( version == "5.1(1)" ) flag = TRUE;
if ( version == "5.1(1a)" ) flag = TRUE;
if ( version == "5.1(3)" ) flag = TRUE;
if ( version == "5.1(4)" ) flag = TRUE;
if ( version == "5.1(5)" ) flag = TRUE;
if ( version == "5.1(6)" ) flag = TRUE;
if ( version == "5.2(1)" ) flag = TRUE;
if ( version == "5.2(3a)" ) flag = TRUE;
if ( version == "5.2(4)" ) flag = TRUE;
if ( version == "5.2(5)" ) flag = TRUE;
if ( version == "5.2(7)" ) flag = TRUE;
if ( version == "5.2(9)" ) flag = TRUE;
if ( version == "6.0(1)" ) flag = TRUE;
if ( version == "6.0(2)" ) flag = TRUE;
if ( version == "6.0(3)" ) flag = TRUE;
if ( version == "6.0(4)" ) flag = TRUE;
if ( version == "6.1(1)" ) flag = TRUE;
if ( version == "6.1(2)" ) flag = TRUE;
if ( version == "6.1(3)" ) flag = TRUE;
if ( version == "6.1(4)" ) flag = TRUE;
if ( version == "6.1(4a)" ) flag = TRUE;
if ( version == "6.1(5)" ) flag = TRUE;
if ( version == "6.2(2)" ) flag = TRUE;
if ( version == "6.2(2a)" ) flag = TRUE;
if ( version == "6.2(6)" ) flag = TRUE;
if ( version == "6.2(6b)" ) flag = TRUE;
if ( version == "6.2(8)" ) flag = TRUE;
if ( version == "6.2(8a)" ) flag = TRUE;
if ( version == "6.2(8b)" ) flag = TRUE;
if ( version == "6.2(10)" ) flag = TRUE;
if ( version == "6.2(12)" ) flag = TRUE;
if ( version == "6.2(14)" ) flag = TRUE;
if ( version == "6.2(14)S1" ) flag = TRUE;
if ( version == "7.2(0)N1(0.1)" ) flag = TRUE;
if ( version == "7.3(0)D1(1)" ) flag = TRUE;

if (!flag) audit(AUDIT_INST_VER_NOT_VULN, "Cisco NX-OS software", version);

if (get_kb_item("Host/local_checks_enabled"))
{
  flag = FALSE;

  # Check for OTV feature
  buf = cisco_command_kb_item("Host/Cisco/Config/show_running-config", "show running-config");
  if (check_cisco_result(buf))
  {
    if (preg(multiline:TRUE, pattern:"^(\s+)?(feature otv|otv join-interface)", string:buf))
    flag = TRUE;
  }
  else if (cisco_needs_enable(buf)) override = TRUE;
}

if (flag || override)
{
  security_report_cisco(
    port     : 0,
    severity : SECURITY_HOLE,
    override : override,
    version  : version,
    bug_id   : 'CSCuy95701',
    cmds     : make_list('show running-config')
  );
} else audit(AUDIT_HOST_NOT, "affected");

References