Vulnerabilities > CVE-2019-1697 - Improper Input Validation vulnerability in Cisco Adaptive Security Appliance Software

047910
CVSS 7.5 - HIGH
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
NONE
Integrity impact
NONE
Availability impact
HIGH
network
low complexity
cisco
CWE-20
nessus
NVD
Published: 2019-05-03
Updated: 2023-08-15

Summary

A vulnerability in the implementation of the Lightweight Directory Access Protocol (LDAP) feature in Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. The vulnerabilities are due to the improper parsing of LDAP packets sent to an affected device. An attacker could exploit these vulnerabilities by sending a crafted LDAP packet, using Basic Encoding Rules (BER), to be processed by an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition.

Vulnerable Configurations

Part Description Count
Application
Cisco
637
OS
Cisco
100
Hardware
Cisco
12

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.
  • Server Side Include (SSI) Injection
    An attacker can use Server Side Include (SSI) Injection to send code to a web application that then gets executed by the web server. Doing so enables the attacker to achieve similar results to Cross Site Scripting, viz., arbitrary code execution and information disclosure, albeit on a more limited scale, since the SSI directives are nowhere near as powerful as a full-fledged scripting language. Nonetheless, the attacker can conveniently gain access to sensitive files, such as password files, and execute shell commands.
  • Cross Zone Scripting
    An attacker is able to cause a victim to load content into their web-browser that bypasses security zone controls and gain access to increased privileges to execute scripting code or other web objects such as unsigned ActiveX controls or applets. This is a privilege elevation attack targeted at zone-based web-browser security. In a zone-based model, pages belong to one of a set of zones corresponding to the level of privilege assigned to that page. Pages in an untrusted zone would have a lesser level of access to the system and/or be restricted in the types of executable content it was allowed to invoke. In a cross-zone scripting attack, a page that should be assigned to a less privileged zone is granted the privileges of a more trusted zone. This can be accomplished by exploiting bugs in the browser, exploiting incorrect configuration in the zone controls, through a cross-site scripting attack that causes the attackers' content to be treated as coming from a more trusted page, or by leveraging some piece of system functionality that is accessible from both the trusted and less trusted zone. This attack differs from "Restful Privilege Escalation" in that the latter correlates to the inadequate securing of RESTful access methods (such as HTTP DELETE) on the server, while cross-zone scripting attacks the concept of security zones as implemented by a browser.
  • Cross Site Scripting through Log Files
    An attacker may leverage a system weakness where logs are susceptible to log injection to insert scripts into the system's logs. If these logs are later viewed by an administrator through a thin administrative interface and the log data is not properly HTML encoded before being written to the page, the attackers' scripts stored in the log will be executed in the administrative interface with potentially serious consequences. This attack pattern is really a combination of two other attack patterns: log injection and stored cross site scripting.
  • Command Line Execution through SQL Injection
    An attacker uses standard SQL injection methods to inject data into the command line for execution. This could be done directly through misuse of directives such as MSSQL_xp_cmdshell or indirectly through injection of data into the database that would be interpreted as shell commands. Sometime later, an unscrupulous backend application (or could be part of the functionality of the same application) fetches the injected data stored in the database and uses this data as command line arguments without performing proper validation. The malicious data escapes that data plane by spawning new commands to be executed on the host.

Nessus

  • NASL familyCISCO
    NASL idCISCO-SA-20190501-ASA-LDAPDOS.NASL
    descriptionAccording to its self-reported version, the Cisco ASA device is affected by a vulnerability in the implementation of the Lightweight Directory Access Protocol (LDAP) feature in Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition.The vulnerabilities are due to the improper parsing of LDAP packets sent to an affected device. An attacker could exploit these vulnerabilities by sending a crafted LDAP packet, using Basic Encoding Rules (BER), to be processed by an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. (CVE-2019-1697) Please see the included Cisco BIDs and Cisco Security Advisory for more information
    last seen2020-06-05
    modified2020-05-29
    plugin id136973
    published2020-05-29
    reporterThis script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/136973
    titleCisco Adaptive Security Appliance Software Lightweight Directory Access Protocol Denial of Service Vulnerability (cisco-sa-20190501-asa-ftds-ldapdos)
    code
    #TRUSTED 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
#
# (C) Tenable Network Security, Inc.
#

include('compat.inc');

if (description)
{
  script_id(136973);
  script_version("1.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/06/04");

  script_cve_id("CVE-2019-1697");
  script_bugtraq_id(108182);
  script_xref(name:"CISCO-BUG-ID", value:"CSCvn20985");
  script_xref(name:"CISCO-SA", value:"cisco-sa-20190501-asa-ftds-ldapdos");

  script_name(english:"Cisco Adaptive Security Appliance Software Lightweight Directory Access Protocol Denial of Service Vulnerability (cisco-sa-20190501-asa-ftds-ldapdos)");
  script_summary(english:"Checks the ASA version.");

  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 ASA device is affected by a vulnerability 
in the implementation of the Lightweight Directory Access Protocol (LDAP) feature in Cisco
Adaptive Security Appliance (ASA) Software and Firepower
Threat Defense (FTD) Software could allow an
unauthenticated, remote attacker to cause an affected
device to reload, resulting in a denial of service (DoS)
condition.The vulnerabilities are due to the improper
parsing of LDAP packets sent to an affected device. An
attacker could exploit these vulnerabilities by sending
a crafted LDAP packet, using Basic Encoding Rules (BER),
to be processed by an affected device. A successful
exploit could allow the attacker to cause the affected
device to reload, resulting in a DoS condition.
(CVE-2019-1697)

Please see the included Cisco BIDs and Cisco Security Advisory for
more information");
  # https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190501-asa-ftds-ldapdos
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?bc6d5791");
  script_set_attribute(attribute:"see_also", value:"https://bst.cloudapps.cisco.com/bugsearch/bug/CSCvn20985");
  script_set_attribute(attribute:"solution", value:
"Upgrade to the relevant fixed version referenced in Cisco bug ID
CSCvn20985");
  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: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-2019-1697");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_cwe_id(20);

  script_set_attribute(attribute:"vuln_publication_date", value:"2019/05/01");
  script_set_attribute(attribute:"patch_publication_date", value:"2019/05/01");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/05/29");

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

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

model = product_info['model'];
if (model =~ '^55[0-9][0-9]' || model =~ '^1000v')
  audit(AUDIT_HOST_NOT, 'an affected Cisco ASA product');

vuln_ranges = [
  {'min_ver' : '9.6',   'fix_ver' : '9.6.4.25'},
  {'min_ver' : '9.7',   'fix_ver' : '9.8.4'},
  {'min_ver' : '9.9',   'fix_ver' : '9.9.2.50'},
  {'min_ver' : '9.10',  'fix_ver' : '9.10.1.17'}
];

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

reporting = make_array(
  'port'     , 0,
  'severity' , SECURITY_HOLE,
  'version'  , product_info['version'],
  'bug_id'   , 'CSCvn20985',
  'cmds'     , make_list('show aaa-server protocol ldap')
);

cisco::check_and_report(
  product_info:product_info,
  workarounds:workarounds,
  workaround_params:workaround_params,
  reporting:reporting,
  vuln_ranges:vuln_ranges
);
  • NASL familyCISCO
    NASL idCISCO-SA-20190501-ASA-FTDS-LDAPDOS.NASL
    descriptionAccording to its self-reported version, Cisco Firepower Threat Defense Software is affected by a vulnerability in the implementation of the Lightweight Directory Access Protocol (LDAP) feature in Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition.The vulnerabilities are due to the improper parsing of LDAP packets sent to an affected device. An attacker could exploit these vulnerabilities by sending a crafted LDAP packet, using Basic Encoding Rules (BER), to be processed by an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. (CVE-2019-1697) Please see the included Cisco BIDs and Cisco Security Advisory for more information
    last seen2020-06-05
    modified2020-05-29
    plugin id136972
    published2020-05-29
    reporterThis script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/136972
    titleCisco Adaptive Security Appliance Software and Firepower Threat Defense Software Lightweight Directory Access Protocol Denial of Service Vulnerability (cisco-sa-20190501-asa-ftds-ldapdos)

References