Vulnerabilities > CVE-2019-1983 - Improper Input Validation vulnerability in Cisco Asyncos and Content Security Management Appliance

047910
CVSS 5.3 - MEDIUM
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
NONE
Integrity impact
NONE
Availability impact
LOW
network
low complexity
cisco
CWE-20
nessus
NVD
Published: 2020-09-23
Updated: 2020-10-01

Summary

A vulnerability in the email message filtering feature of Cisco AsyncOS Software for Cisco Email Security Appliance (ESA) and Cisco Content Security Management Appliance (SMA) could allow an unauthenticated, remote attacker to cause repeated crashes in some internal processes that are running on the affected devices, resulting in a denial of service (DoS) condition. The vulnerability is due to insufficient input validation of email attachments. An attacker could exploit this vulnerability by sending an email message with a crafted attachment through an affected device. A successful exploit could allow the attacker to cause specific processes to crash repeatedly, resulting in the complete unavailability of both the Cisco Advanced Malware Protection (AMP) and message tracking features and in severe performance degradation while processing email. After the affected processes restart, the software resumes filtering for the same attachment, causing the affected processes to crash and restart again. A successful exploit could also allow the attacker to cause a repeated DoS condition. Manual intervention may be required to recover from this situation.

Vulnerable Configurations

Part Description Count
Application
Cisco
3
OS
Cisco
133

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-20200219-ESA-SMA-DOS_CSCVO89192_FOR_ESA.NASL
    descriptionAccording to its self-reported version, Cisco Email Security Appliance (ESA) is affected by an input-validation flaw related to the email message filtering feature that allows denial of service attacks. Please see the included Cisco BID and Cisco Security Advisory for more information
    last seen2020-03-17
    modified2020-02-25
    plugin id133961
    published2020-02-25
    reporterThis script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/133961
    titleCisco Email Security Appliance Denial of Service Vulnerability (CSCvo89192)
    code
    #TRUSTED 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
#
# (C) Tenable Network Security, Inc.
#

include('compat.inc');

if (description)
{
  script_id(133961);
  script_version("1.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/02/27");

  script_cve_id("CVE-2019-1983");
  script_xref(name:"CISCO-BUG-ID", value:"CSCvo89192");
  script_xref(name:"CISCO-SA", value:"cisco-sa-20200219-esa-sma-dos");
  script_xref(name:"IAVA", value:"2020-A-0045");

  script_name(english:"Cisco Email Security Appliance Denial of Service Vulnerability (CSCvo89192)");

  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, Cisco Email Security
Appliance (ESA) is affected by an input-validation flaw related to
the email message filtering feature that allows denial of service
attacks.

Please see the included Cisco BID and Cisco Security Advisory for more
information");
  # https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20200219-esa-sma-dos
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?b12c8fec");
  script_set_attribute(attribute:"see_also", value:"https://bst.cloudapps.cisco.com/bugsearch/bug/CSCvo89192");
  script_set_attribute(attribute:"solution", value:
"Upgrade to the relevant fixed version referenced in Cisco bug ID CSCvo89192");
  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-2019-1983");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2020/02/19");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/02/19");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/02/25");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:cisco:email_security_appliance_(esa)");
  script_set_attribute(attribute:"stig_severity", value:"II");
  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_esa_version.nasl");
  script_require_keys("Host/AsyncOS/Cisco Email Security Appliance/Version");

  exit(0);
}

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

product_info = cisco::get_product_info(name:'Cisco Email Security Appliance (ESA)');

vuln_ranges = [
  { 'min_ver' : '0', 'fix_ver' : '11.0.3.251' },
  { 'min_ver' : '12', 'fix_ver' : '12.5.0.059' }
];

reporting = make_array(
  'port'          , 0,
  'severity'      , SECURITY_WARNING,
  'version'       , product_info['version'],
  'bug_id'        , 'CSCvo89192',
  'disable_caveat', TRUE
);

cisco::check_and_report(product_info:product_info, reporting:reporting, vuln_ranges:vuln_ranges);
  • NASL familyCISCO
    NASL idCISCO-SA-20200219-ESA-SMA-DOS_CSCVO89182_FOR_SMA.NASL
    descriptionAccording to its self-reported version, the Cisco Content Security Management Appliance (SMA) is affected by an input-validation flaw related to the email message filtering feature that allows denial of service attacks. Please see the included Cisco BID and Cisco Security Advisory for more information
    last seen2020-03-17
    modified2020-02-25
    plugin id133960
    published2020-02-25
    reporterThis script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/133960
    titleCisco Content Security Management Appliance Denial of Service Vulnerability (CSCvo89182)
    code
    #TRUSTED 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
#
# (C) Tenable Network Security, Inc.
#

include('compat.inc');

if (description)
{
  script_id(133960);
  script_version("1.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/02/27");

  script_cve_id("CVE-2019-1983");
  script_xref(name:"CISCO-BUG-ID", value:"CSCvo89182");
  script_xref(name:"CISCO-SA", value:"cisco-sa-20200219-esa-sma-dos");
  script_xref(name:"IAVA", value:"2020-A-0045");

  script_name(english:"Cisco Content Security Management Appliance Denial of Service Vulnerability (CSCvo89182)");
  script_summary(english:"Checks the Cisco Content Security Management Appliance (SMA) 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 Content
Security Management Appliance (SMA) is affected by an input-validation
flaw related to the email message filtering feature that allows denial
of service attacks.

Please see the included Cisco BID and Cisco Security Advisory for more
information");
  # https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20200219-esa-sma-dos
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?b12c8fec");
  script_set_attribute(attribute:"see_also", value:"https://bst.cloudapps.cisco.com/bugsearch/bug/CSCvo89182");
  script_set_attribute(attribute:"solution", value:
"Upgrade to the relevant fixed version referenced in Cisco bug ID CSCvo89182");
  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-2019-1983");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2020/02/19");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/02/19");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/02/25");

  script_set_attribute(attribute:"plugin_type", value:"combined");
  script_set_attribute(attribute:"cpe", value:"cpe:/h:cisco:content_security_management_appliance");
  script_set_attribute(attribute:"stig_severity", value:"II");
  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_sma_version.nasl");
  script_require_keys("Host/AsyncOS/Cisco Content Security Management Appliance/DisplayVersion", "Host/AsyncOS/Cisco Content Security Management Appliance/Version");

  exit(0);
}

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

product_info = cisco::get_product_info(name:"Cisco Content Security Management Appliance (SMA)");

vuln_ranges = [
  { 'min_ver' : '0', 'fix_ver' : '11.0.1.161' },
  { 'min_ver' : '12', 'fix_ver' : '12.5.0.633' }
];

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


reporting = make_array(
  'port'          , 0,
  'severity'      , SECURITY_WARNING,
  'version'       , product_info['version'],
  'bug_id'        , 'CSCvo89182',
  'disable_caveat', TRUE
);

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

References