Vulnerabilities > CVE-2019-15256 - Resource Exhaustion vulnerability in Cisco products

047910
CVSS 8.6 - HIGH
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
NONE
Integrity impact
NONE
Availability impact
HIGH
network
low complexity
cisco
CWE-400
nessus
NVD
Published: 2019-10-02
Updated: 2023-08-15

Summary

A vulnerability in the Internet Key Exchange version 1 (IKEv1) feature of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a reload of an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to improper management of system memory. An attacker could exploit this vulnerability by sending malicious IKEv1 traffic to an affected device. The attacker does not need valid credentials to authenticate the VPN session, nor does the attacker's source address need to match a peer statement in the crypto map applied to the ingress interface of the affected device. An exploit could allow the attacker to exhaust system memory resources, leading to a reload of an affected device.

Vulnerable Configurations

Part Description Count
Application
Cisco
73
OS
Cisco
64
Hardware
Cisco
11

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • XML Ping of the Death
    An attacker initiates a resource depletion attack where a large number of small XML messages are delivered at a sufficiently rapid rate to cause a denial of service or crash of the target. Transactions such as repetitive SOAP transactions can deplete resources faster than a simple flooding attack because of the additional resources used by the SOAP protocol and the resources necessary to process SOAP messages. The transactions used are immaterial as long as they cause resource utilization on the target. In other words, this is a normal flooding attack augmented by using messages that will require extra processing on the target.
  • XML Entity Expansion
    An attacker submits an XML document to a target application where the XML document uses nested entity expansion to produce an excessively large output XML. XML allows the definition of macro-like structures that can be used to simplify the creation of complex structures. However, this capability can be abused to create excessive demands on a processor's CPU and memory. A small number of nested expansions can result in an exponential growth in demands on memory.
  • Inducing Account Lockout
    An attacker leverages the security functionality of the system aimed at thwarting potential attacks to launch a denial of service attack against a legitimate system user. Many systems, for instance, implement a password throttling mechanism that locks an account after a certain number of incorrect log in attempts. An attacker can leverage this throttling mechanism to lock a legitimate user out of their own account. The weakness that is being leveraged by an attacker is the very security feature that has been put in place to counteract attacks.
  • Violating Implicit Assumptions Regarding XML Content (aka XML Denial of Service (XDoS))
    XML Denial of Service (XDoS) can be applied to any technology that utilizes XML data. This is, of course, most distributed systems technology including Java, .Net, databases, and so on. XDoS is most closely associated with web services, SOAP, and Rest, because remote service requesters can post malicious XML payloads to the service provider designed to exhaust the service provider's memory, CPU, and/or disk space. The main weakness in XDoS is that the service provider generally must inspect, parse, and validate the XML messages to determine routing, workflow, security considerations, and so on. It is exactly these inspection, parsing, and validation routines that XDoS targets. There are three primary attack vectors that XDoS can navigate Target CPU through recursion: attacker creates a recursive payload and sends to service provider Target memory through jumbo payloads: service provider uses DOM to parse XML. DOM creates in memory representation of XML document, but when document is very large (for example, north of 1 Gb) service provider host may exhaust memory trying to build memory objects. XML Ping of death: attack service provider with numerous small files that clog the system. All of the above attacks exploit the loosely coupled nature of web services, where the service provider has little to no control over the service requester and any messages the service requester sends.

Nessus

  • NASL familyCISCO
    NASL idCISCO-SA-20191002-ASA-FTD-IKEV1-DOS-FTD.NASL
    descriptionAccording to its self-reported version the Cisco Firepower Threat Defense (FTD) Software running on the remote device is affected by a denial of service (DoS) vulnerability in the Internet Key Exchange version 1 (IKEv1) feature of Cisco Firepower Threat Defense (FTD) Software. The vulnerability is due to improper management of system memory when handling IKEv1 traffic. An unauthenticated, remote attacker can exploit this, via malicious IKEv1 traffic, to cause a reload of the affected device. Please see the included Cisco BID and Cisco Security Advisory for more information.
    last seen2020-06-13
    modified2020-02-20
    plugin id133842
    published2020-02-20
    reporterThis script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/133842
    titleCisco Firepower Threat Defense (FTD) Software IKEv1 DoS (cisco-sa-20191002-asa-ftd-ikev1-dos)
    code
    #TRUSTED 0943db6eb071bdc6ae4791c9940adada71e0b5ab40b7b998acbb9f144adaaf24a54f8f364b03b2dc531e09e438560fed17e48aa845eaadb7fe850e74803d630f98854b651baadc61da807d131c094ff572e4fdbf02e709bc7d4320bafd8179c988f0de39b0e7c6de12ddad82635d32b1ba0eb8eaa9fd077ae66567d7c9e68c0a7bfd9dfaacf75e55b5c57ca214bafde4affba2646f31be48e052bcf32d8a11683e81c7dc60da5703363043d3de9487741e06f9fce4c8af8819c4684d79715fe142e57ce5c33caeb9617554b88c23a2c7167a17f828dc1083600f985ca3853f2ba910ca2cce8c6ce0c728368f5434cd054753fc5469d667b1734bcd7cbef79d23fdde5f59738ca6d4697599a42b5c3850b8752d1be5981d69a3cd6b82d3fa415af8e3fff3345b99b032425541932918186afdc64e80818b7963a2db30916c20b1f6d584b85670c5d068c6ed482bfe3ab0f65a769cc6cb6178384ce98e6598e1fbb4ea29a4bee433be3854b6dfe98d440af64acd2ec161dc8a7568bb7d926e7fcc0a27d2d6e1b629aab6d6d5a3ea5d38efeaeacf02974945be8a7fee3cfdd7910178ab60104306798be9bbdda6fa69a1b961065b55d5907c7a8d357eedf938e962e166e6ad50239852a1d1a5674cb5fb27af44d4658c3baaf60cc4c69923ce3feece808288476c1a784bf9094cea204125a7ff27b2f12fe959021a783eecf56543
#
# (C) Tenable Network Security, Inc.
#

include('compat.inc');

if (description)
{
  script_id(133842);
  script_version("1.6");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/06/12");

  script_cve_id("CVE-2019-15256");
  script_xref(name:"CISCO-BUG-ID", value:"CSCvo11077");
  script_xref(name:"CISCO-SA", value:"cisco-sa-20191002-asa-ftd-ikev1-dos");
  script_xref(name:"IAVA", value:"2019-A-0370");

  script_name(english:"Cisco Firepower Threat Defense (FTD) Software IKEv1 DoS (cisco-sa-20191002-asa-ftd-ikev1-dos)");

  script_set_attribute(attribute:"synopsis", value:
"The packet inspection software installed on the remote host is affected by a denial of service vulnerability.");
  script_set_attribute(attribute:"description", value:
"According to its self-reported version the Cisco Firepower Threat Defense (FTD) Software running on the remote device
is affected by a denial of service (DoS) vulnerability in the Internet Key Exchange version 1 (IKEv1) feature of Cisco
Firepower Threat Defense (FTD) Software. The vulnerability is due to improper management of system memory when handling
IKEv1 traffic. An unauthenticated, remote attacker can exploit this, via malicious IKEv1 traffic, to cause a reload of
the affected device.

Please see the included Cisco BID and Cisco Security Advisory for more information.");
  # https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20191002-asa-ftd-ikev1-dos
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?2df7518b");
  script_set_attribute(attribute:"see_also", value:"https://bst.cloudapps.cisco.com/bugsearch/bug/CSCvo11077");
  script_set_attribute(attribute:"solution", value:
"Upgrade to a fixed version referenced in the Cisco advisory.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/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:C/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-2019-15256");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_cwe_id(399);

  script_set_attribute(attribute:"vuln_publication_date", value:"2019/10/02");
  script_set_attribute(attribute:"patch_publication_date", value:"2019/10/02");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/02/20");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:cisco:firepower");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:cisco:firepower_threat_defense");
  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) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("cisco_enumerate_firepower.nbin");
  script_require_keys("installed_sw/Cisco Firepower Threat Defense", "Host/Cisco/Firepower");

  exit(0);
}

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

product_info = cisco::get_product_info(name:'Cisco Firepower Threat Defense');

vuln_ranges = [
  {'min_ver' : '6.2.0',  'fix_ver' : '6.2.3.11'},
  {'min_ver' : '6.3.0',  'fix_ver' : '6.3.0.2'}
];

is_ftd_cli = get_kb_item_or_exit("Host/Cisco/Firepower/is_ftd_cli");
if (!is_ftd_cli)
{
  if (report_paranoia < 2)
    audit(AUDIT_PARANOID);
  else
  {
    workarounds = make_list();
    extra = 'Note that Nessus was unable to check for workarounds';
  }
}
else
{
  workarounds = make_list(CISCO_WORKAROUNDS['IKEv1_enabled']);
  cmds = make_list('show running-config');
}

reporting = make_array(
  'port'     , 0,
  'severity' , SECURITY_HOLE,
  'version'  , product_info['version'],
  'bug_id'   , 'CSCvo11077',
  'extra'    , extra
);

if (max_index(cmds) > 0)
  reporting['cmds'] = cmds;

cisco::check_and_report(
  product_info:product_info,
  workarounds:workarounds,
  reporting:reporting,
  vuln_ranges:vuln_ranges
);
  • NASL familyCISCO
    NASL idCISCO-SA-20191002-ASA-FTD-IKEV1-DOS-ASA.NASL
    descriptionAccording to its self-reported version the Cisco Adaptive Security Appliance (ASA) Software running on the remote device is affected by a denial of service (DoS) vulnerability in the Internet Key Exchange version 1 (IKEv1) feature of Cisco Adaptive Security Appliance (ASA) Software. The vulnerability is due to improper management of system memory when handling IKEv1 traffic. An unauthenticated, remote attacker can exploit this, via malicious IKEv1 traffic, to cause a reload of the affected device. Please see the included Cisco BID and Cisco Security Advisory for more information.
    last seen2020-03-17
    modified2020-02-20
    plugin id133841
    published2020-02-20
    reporterThis script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/133841
    titleCisco Adaptive Security Appliance Software IKEv1 DoS (cisco-sa-20191002-asa-ftd-ikev1-dos)
    code
    #TRUSTED 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
#
# (C) Tenable Network Security, Inc.
#

include('compat.inc');

if (description)
{
  script_id(133841);
  script_version("1.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/02/24");

  script_cve_id("CVE-2019-15256");
  script_xref(name:"CISCO-BUG-ID", value:"CSCvo11077");
  script_xref(name:"CISCO-SA", value:"cisco-sa-20191002-asa-ftd-ikev1-dos");
  script_xref(name:"IAVA", value:"2019-A-0370");

  script_name(english:"Cisco Adaptive Security Appliance Software IKEv1 DoS (cisco-sa-20191002-asa-ftd-ikev1-dos)");

  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 Adaptive Security Appliance (ASA) Software running on the remote
device is affected by a denial of service (DoS) vulnerability in the Internet Key Exchange version 1 (IKEv1) feature of
Cisco Adaptive Security Appliance (ASA) Software. The vulnerability is due to improper management of system memory when
handling IKEv1 traffic. An unauthenticated, remote attacker can exploit this, via malicious IKEv1 traffic, to cause a
reload of the affected device.

Please see the included Cisco BID and Cisco Security Advisory for more information.");
  # https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20191002-asa-ftd-ikev1-dos
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?2df7518b");
  script_set_attribute(attribute:"see_also", value:"https://bst.cloudapps.cisco.com/bugsearch/bug/CSCvo11077");
  script_set_attribute(attribute:"solution", value:
"Upgrade to a fixed version referenced in the Cisco advisory.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/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:C/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-2019-15256");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_cwe_id(399);

  script_set_attribute(attribute:"vuln_publication_date", value:"2019/10/02");
  script_set_attribute(attribute:"patch_publication_date", value:"2019/10/02");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/02/20");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:cisco:adaptive_security_appliance_software");
  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) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info.nasl", "os_fingerprint.nasl");
  script_require_keys("Host/Cisco/ASA", "Host/Cisco/ASA/model");

  exit(0);
}

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

product_info = cisco::get_product_info(name:'Cisco Adaptive Security Appliance (ASA) Software');

if (
  product_info.model != 'v' &&                    # ASAv
  product_info.model !~ '^21[0-9][0-9]($|[^0-9])' # Firepower 2100 SSA
) audit(AUDIT_HOST_NOT, 'an affected Cisco ASA product');

vuln_ranges = [
  {'min_ver' : '9.7',  'fix_ver' : '9.8.3.26'},
  {'min_ver' : '9.9',  'fix_ver' : '9.9.2.47'},
  {'min_ver' : '9.10',  'fix_ver' : '9.10.1.17'},
  {'min_ver' : '9.12',  'fix_ver' : '9.12.2'}
];

workarounds = make_list(CISCO_WORKAROUNDS['IKEv1_enabled']);
workaround_params = make_list();

reporting = make_array(
  'port'     , 0,
  'severity' , SECURITY_HOLE,
  'version'  , product_info['version'],
  'bug_id'   , 'CSCvo11077'
);

cisco::check_and_report(
  product_info:product_info,
  workarounds:workarounds,
  workaround_params:workaround_params,
  reporting:reporting,
  vuln_ranges:vuln_ranges
);

References