Vulnerabilities > CVE-2014-3295 - Improper Authentication vulnerability in Cisco Nx-Os

047910
CVSS 4.8 - MEDIUM
Attack vector
ADJACENT_NETWORK
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
NONE
Integrity impact
PARTIAL
Availability impact
PARTIAL
low complexity
cisco
CWE-287
nessus

Summary

The HSRP implementation in Cisco NX-OS 6.2(2a) and earlier allows remote attackers to bypass authentication and cause a denial of service (group-member state modification and traffic blackholing) via malformed HSRP packets, aka Bug ID CSCup11309.

Vulnerable Configurations

Part Description Count
OS
Cisco
244

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Authentication Abuse
    An attacker obtains unauthorized access to an application, service or device either through knowledge of the inherent weaknesses of an authentication mechanism, or by exploiting a flaw in the authentication scheme's implementation. In such an attack an authentication mechanism is functioning but a carefully controlled sequence of events causes the mechanism to grant access to the attacker. This attack may exploit assumptions made by the target's authentication procedures, such as assumptions regarding trust relationships or assumptions regarding the generation of secret values. This attack differs from Authentication Bypass attacks in that Authentication Abuse allows the attacker to be certified as a valid user through illegitimate means, while Authentication Bypass allows the user to access protected material without ever being certified as an authenticated user. This attack does not rely on prior sessions established by successfully authenticating users, as relied upon for the "Exploitation of Session Variables, Resource IDs and other Trusted Credentials" attack patterns.
  • Exploiting Trust in Client (aka Make the Client Invisible)
    An attack of this type exploits a programs' vulnerabilities in client/server communication channel authentication and data integrity. It leverages the implicit trust a server places in the client, or more importantly, that which the server believes is the client. An attacker executes this type of attack by placing themselves in the communication channel between client and server such that communication directly to the server is possible where the server believes it is communicating only with a valid client. There are numerous variations of this type of attack.
  • Utilizing REST's Trust in the System Resource to Register Man in the Middle
    This attack utilizes a REST(REpresentational State Transfer)-style applications' trust in the system resources and environment to place man in the middle once SSL is terminated. Rest applications premise is that they leverage existing infrastructure to deliver web services functionality. An example of this is a Rest application that uses HTTP Get methods and receives a HTTP response with an XML document. These Rest style web services are deployed on existing infrastructure such as Apache and IIS web servers with no SOAP stack required. Unfortunately from a security standpoint, there frequently is no interoperable identity security mechanism deployed, so Rest developers often fall back to SSL to deliver security. In large data centers, SSL is typically terminated at the edge of the network - at the firewall, load balancer, or router. Once the SSL is terminated the HTTP request is in the clear (unless developers have hashed or encrypted the values, but this is rare). The attacker can utilize a sniffer such as Wireshark to snapshot the credentials, such as username and password that are passed in the clear once SSL is terminated. Once the attacker gathers these credentials, they can submit requests to the web service provider just as authorized user do. There is not typically an authentication on the client side, beyond what is passed in the request itself so once this is compromised, then this is generally sufficient to compromise the service's authentication scheme.
  • Man in the Middle Attack
    This type of attack targets the communication between two components (typically client and server). The attacker places himself in the communication channel between the two components. Whenever one component attempts to communicate with the other (data flow, authentication challenges, etc.), the data first goes to the attacker, who has the opportunity to observe or alter it, and it is then passed on to the other component as if it was never intercepted. This interposition is transparent leaving the two compromised components unaware of the potential corruption or leakage of their communications. The potential for Man-in-the-Middle attacks yields an implicit lack of trust in communication or identify between two components.

Nessus

NASL familyCISCO
NASL idCISCO-SN-CVE-2014-3295-NXOS.NASL
descriptionThe remote Cisco device contains a flaw in the Hot Standby Router Protocol (HSRP) authentication. A remote attacker, using a specially crafted HSRP packet, can bypass HSRP authentication and configure HSRP group members to the SPEAK state, causing a denial of service.
last seen2020-06-01
modified2020-06-02
plugin id83904
published2015-05-30
reporterThis script is Copyright (C) 2015-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
sourcehttps://www.tenable.com/plugins/nessus/83904
titleCisco NX-OS HSRP DoS (CSCup11309)
code
#TRUSTED 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
#
# (C) Tenable Network Security, Inc.
#

include("compat.inc");

if (description)
{
  script_id(83904);
  script_version("1.9");
  script_cvs_date("Date: 2019/11/22");

  script_cve_id("CVE-2014-3295");
  script_bugtraq_id(67983);
  script_xref(name:"CISCO-BUG-ID", value:"CSCup11309");

  script_name(english:"Cisco NX-OS HSRP DoS (CSCup11309)");
  script_summary(english:"Checks the NX-OS version.");

  script_set_attribute(attribute:"synopsis", value:
"The remote device is affected by a denial of service vulnerability.");
  script_set_attribute(attribute:"description", value:
"The remote Cisco device contains a flaw in the Hot Standby Router
Protocol (HSRP) authentication. A remote attacker, using a specially
crafted HSRP packet, can bypass HSRP authentication and configure HSRP
group members to the SPEAK state, causing a denial of service.");
  script_set_attribute(attribute:"see_also", value:"https://tools.cisco.com/security/center/viewAlert.x?alertId=34585");
  script_set_attribute(attribute:"see_also", value:"https://tools.cisco.com/bugsearch/bug/CSCup11309");
  script_set_attribute(attribute:"solution", value:
"Upgrade to the relevant fixed version, 6.2(10) or later, as referenced
in Cisco bug ID CSCup11309.");
  script_set_cvss_base_vector("CVSS2#AV:A/AC:L/Au:N/C:N/I:P/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");

  script_set_attribute(attribute:"vuln_publication_date", value:"2014/06/10");
  script_set_attribute(attribute:"patch_publication_date", value:"2014/06/11");
  script_set_attribute(attribute:"plugin_publication_date", value:"2015/05/30");

  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) 2015-2019 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", "Host/local_checks_enabled");

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

flag = 0;
override = 0;

# According to the Note only Nexus 7000 is affected
if (device != 'Nexus' || model !~ "^7[0-9][0-9][0-9]([^0-9]|$)")
  audit(AUDIT_DEVICE_NOT_VULN, device + ' ' + model);

if (version =~ "^[0-5]([^0-9]|$)" ||
    version =~ "^6\.[0-1]([^0-9]|$)" ||
    version =~ "^6\.2\([0-9]([^0-9]|$)"
) flag++;

if (flag)
{
  flag = 0;

  # Check for HSRP enabled
  if (get_kb_item_or_exit("Host/local_checks_enabled"))
  {
    buf = cisco_command_kb_item("Host/Cisco/Config/show_hsrp", "show hsrp");
    if (check_cisco_result(buf))
    {
      if ('HSRP' >< buf) flag++;
    }
    else if (cisco_needs_enable(buf))
    {
      flag++;
      override++;
    }
  }
}


if (flag)
{
  if (report_verbosity > 0)
  {
    report =
    '\n  Cisco bug ID      : CSCup11309' +
    '\n  Installed release : ' + version +
    '\n';
    security_warning(port:0, extra:report + cisco_caveat(override));
  }
  else security_warning(port:0, extra:cisco_caveat(override));
  exit(0);
}
else audit(AUDIT_DEVICE_NOT_VULN, device + ' ' + model, version);;