Vulnerabilities > CVE-2013-6706 - Improper Input Validation vulnerability in Cisco IOS XE

047910
CVSS 0.0 - NONE
Attack vector
UNKNOWN
Attack complexity
UNKNOWN
Privileges required
UNKNOWN
Confidentiality impact
UNKNOWN
Integrity impact
UNKNOWN
Availability impact
UNKNOWN
cisco
CWE-20
nessus
NVD
Published: 2013-11-29
Updated: 2016-11-02

Summary

The Cisco Express Forwarding processing module in Cisco IOS XE allows remote attackers to cause a denial of service (device reload) via crafted MPLS packets that are not properly handled during IP header validation, aka Bug ID CSCuj23992.

Vulnerable Configurations

Part Description Count
OS
Cisco
1

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-SN-CSCUJ23992-IOSXE.NASL
    descriptionAccording to its self-reported version, the remote IOS XE device is affected by a denial of service vulnerability in the Cisco Express Forwarding processing module. The issue is due to improper processing of MPLS packets. When certain additional features are configured, an attacker can exploit this vulnerability by sending MPLS packets to traverse and exit an affected device as IP packets. This may cause the device to reload.
    last seen2020-06-01
    modified2020-06-02
    plugin id78691
    published2014-10-27
    reporterThis script is Copyright (C) 2014-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/78691
    titleCisco IOS XE IP Header Sanity Check DoS (CSCuj23992)
    code
    #TRUSTED 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
#
# (C) Tenable Network Security, Inc.
#

include("compat.inc");

if (description)
{
  script_id(78691);
  script_version("1.9");
  script_cvs_date("Date: 2019/11/25");

  script_cve_id("CVE-2013-6706");
  script_bugtraq_id(63979);
  script_xref(name:"CISCO-BUG-ID", value:"CSCuj23992");

  script_name(english:"Cisco IOS XE IP Header Sanity Check DoS (CSCuj23992)");
  script_summary(english:"Checks the IOS XE version.");

  script_set_attribute(attribute:"synopsis", value:
"The remote device is affected by a denial of service vulnerability.");
  script_set_attribute(attribute:"description", value:
"According to its self-reported version, the remote IOS XE device is
affected by a denial of service vulnerability in the Cisco Express
Forwarding processing module.

The issue is due to improper processing of MPLS packets. When certain
additional features are configured, an attacker can exploit this
vulnerability by sending MPLS packets to traverse and exit an affected
device as IP packets. This may cause the device to reload.");
  script_set_attribute(attribute:"see_also", value:"https://tools.cisco.com/security/center/viewAlert.x?alertId=31950");
  # https://tools.cisco.com/security/center/viewAlert.x?alertId=31950
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?4249565d");
  script_set_attribute(attribute:"solution", value:
"Upgrade to the relevant fixed version referenced in Cisco bug ID
CSCuj23992.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:H/Au:N/C:N/I:N/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2013-6706");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2013/12/02");
  script_set_attribute(attribute:"patch_publication_date", value:"2013/12/02");
  script_set_attribute(attribute:"plugin_publication_date", value:"2014/10/27");

  script_set_attribute(attribute:"potential_vulnerability", value:"true");
  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:cisco:ios_xe");
  script_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2014-2019 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("cisco_ios_xe_version.nasl");
  script_require_keys("Host/Cisco/IOS-XE/Version", "Settings/ParanoidReport");

  exit(0);
}

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

version = get_kb_item_or_exit("Host/Cisco/IOS-XE/Version");

# this advisory only addresses CISCO ASR 1000 series
model = get_kb_item_or_exit("Host/Cisco/IOS-XE/Model");
if (model !~ '^ASR 10[0-9][0-9]($|[^0-9])') audit(AUDIT_HOST_NOT, 'ASR 1000 Series');

if (report_paranoia < 2) audit(AUDIT_PARANOID);

flag = 0;
override = 0;

if (version == '3.9.0S') flag++;
else if (version == '3.9.1S') flag++;

if (get_kb_item("Host/local_checks_enabled"))
{
  if (flag > 0)
  {
    flag = 0;
    buf = cisco_command_kb_item("Host/Cisco/Config/show_running-config", "show running-config");
    if (check_cisco_result(buf))
    {
      if (
        preg(multiline:TRUE, pattern:"ip cef accounting", string:buf) && 
        preg(multiline:TRUE, pattern:"tcp adjust-mss", string:buf)
      ) flag = 1;
    }
    else if (cisco_needs_enable(buf)) { flag = 1; override = 1; }
  }
}

if (flag > 0)
{
  if (report_verbosity > 0)
  {
    report =
      '\n  Cisco bug ID      : CSCuj23992' +
      '\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_HOST_NOT, "affected");
  • NASL familyCISCO
    NASL idCISCO-SN-CSCUJ23992-IOS.NASL
    descriptionAccording to its self-reported version, the remote IOS device is affected by a denial of service vulnerability in the Cisco Express Forwarding processing module. The issue is due to improper processing of MPLS packets. When certain additional features are configured, an attacker can exploit this vulnerability by sending MPLS packets to traverse and exit an affected device as IP packets. This may cause the device to reload.
    last seen2020-06-01
    modified2020-06-02
    plugin id78690
    published2014-10-27
    reporterThis script is Copyright (C) 2014-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/78690
    titleCisco IOS IP Header Sanity Check DoS (CSCuj23992)
    code
    #TRUSTED 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
#
# (C) Tenable Network Security, Inc.
#

include("compat.inc");

if (description)
{
  script_id(78690);
  script_version("1.9");
  script_cvs_date("Date: 2019/11/25");

  script_cve_id("CVE-2013-6706");
  script_bugtraq_id(63979);
  script_xref(name:"CISCO-BUG-ID", value:"CSCuj23992");

  script_name(english:"Cisco IOS IP Header Sanity Check DoS (CSCuj23992)");
  script_summary(english:"Checks the IOS version.");

  script_set_attribute(attribute:"synopsis", value:
"The remote device is affected by a denial of service vulnerability.");
  script_set_attribute(attribute:"description", value:
"According to its self-reported version, the remote IOS device is
affected by a denial of service vulnerability in the Cisco Express
Forwarding processing module.

The issue is due to improper processing of MPLS packets. When certain
additional features are configured, an attacker can exploit this
vulnerability by sending MPLS packets to traverse and exit an affected
device as IP packets. This may cause the device to reload.");
  script_set_attribute(attribute:"see_also", value:"https://tools.cisco.com/security/center/viewAlert.x?alertId=31950");
  # https://tools.cisco.com/security/center/viewAlert.x?alertId=31950
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?4249565d");
  script_set_attribute(attribute:"solution", value:
"Upgrade to the relevant fixed version referenced in Cisco bug ID
CSCuj23992.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:H/Au:N/C:N/I:N/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2013-6706");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2013/12/02");
  script_set_attribute(attribute:"patch_publication_date", value:"2013/12/02");
  script_set_attribute(attribute:"plugin_publication_date", value:"2014/10/27");

  script_set_attribute(attribute:"potential_vulnerability", value:"true");
  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:cisco:ios");
  script_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2014-2019 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("cisco_ios_version.nasl");
  script_require_keys("Host/Cisco/IOS/Version", "Settings/ParanoidReport");

  exit(0);
}

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

version = get_kb_item_or_exit("Host/Cisco/IOS/Version");

# this advisory only addresses CISCO ASR 1000 series
model = get_kb_item_or_exit("Host/Cisco/IOS/Model");
if (model !~ '^ASR 10[0-9][0-9]($|[^0-9])') audit(AUDIT_HOST_NOT, 'ASR 1000 Series');

if (report_paranoia < 2) audit(AUDIT_PARANOID);

flag = 0;
override = 0;

if (version == '15.3(2)S1') flag++;
else if (version == '15.3(2)S') flag++;
else if (version == '15.0(1)S') flag++;

if (get_kb_item("Host/local_checks_enabled"))
{
  if (flag > 0)
  {
    flag = 0;
    buf = cisco_command_kb_item("Host/Cisco/Config/show_running-config", "show running-config");
    if (check_cisco_result(buf))
    {
      if (
        preg(multiline:TRUE, pattern:"ip cef accounting", string:buf) &&
        preg(multiline:TRUE, pattern:"tcp adjust-mss", string:buf)
      ) flag = 1;
    }
    else if (cisco_needs_enable(buf)) { flag = 1; override = 1; }
  }
}

if (flag > 0)
{
  if (report_verbosity > 0)
  {
    report =
      '\n  Cisco bug ID      : CSCuj23992' +
      '\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_HOST_NOT, "affected");

References