Vulnerabilities > CVE-2013-6691 - Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability in Cisco Adaptive Security Appliance Software

047910
CVSS 0.0 - NONE
Attack vector
UNKNOWN
Attack complexity
UNKNOWN
Privileges required
UNKNOWN
Confidentiality impact
UNKNOWN
Integrity impact
UNKNOWN
Availability impact
UNKNOWN

Summary

The WebVPN CIFS implementation in Cisco Adaptive Security Appliance (ASA) Software 9.0(.4.1) and earlier allows remote CIFS servers to cause a denial of service (device reload) via a long share list, aka Bug ID CSCuj83344.

Vulnerable Configurations

Part Description Count
Application
Cisco
352

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.
  • Overflow Buffers
    Buffer Overflow attacks target improper or missing bounds checking on buffer operations, typically triggered by input injected by an attacker. As a consequence, an attacker is able to write past the boundaries of allocated buffer regions in memory, causing a program crash or potentially redirection of execution as per the attackers' choice.
  • Client-side Injection-induced Buffer Overflow
    This type of attack exploits a buffer overflow vulnerability in targeted client software through injection of malicious content from a custom-built hostile service.
  • Filter Failure through Buffer Overflow
    In this attack, the idea is to cause an active filter to fail by causing an oversized transaction. An attacker may try to feed overly long input strings to the program in an attempt to overwhelm the filter (by causing a buffer overflow) and hoping that the filter does not fail securely (i.e. the user input is let into the system unfiltered).
  • MIME Conversion
    An attacker exploits a weakness in the MIME conversion routine to cause a buffer overflow and gain control over the mail server machine. The MIME system is designed to allow various different information formats to be interpreted and sent via e-mail. Attack points exist when data are converted to MIME compatible format and back.

Nessus

NASL familyCISCO
NASL idCISCO-SN-CSCUJ83344-ASA.NASL
descriptionAccording to its banner, the version of the remote Cisco ASA device is affected by a denial of service vulnerability in the WebVPN CIFS (Common Internet File System) access function due to missing bounds checks on received responses when enumerating large amounts of shares on a CIFS server. A remote, authenticated attacker can exploit this issue by attempting to list the shares of a CIFS server with a large amount of shares.
last seen2019-10-28
modified2014-08-28
plugin id77411
published2014-08-28
reporterThis script is Copyright (C) 2014-2018 Tenable Network Security, Inc.
sourcehttps://www.tenable.com/plugins/nessus/77411
titleCisco ASA WebVPN CIFS Share Enumeration DoS (CSCuj83344)
code
#TRUSTED 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
#
# (C) Tenable Network Security, Inc.
#

include("compat.inc");

if (description)
{
  script_id(77411);
  script_version("1.7");
  script_set_attribute(attribute:"plugin_modification_date", value:"2018/11/15");

  script_cve_id("CVE-2013-6691");
  script_bugtraq_id(68517);
  script_xref(name:"CISCO-BUG-ID", value:"CSCuj83344");

  script_name(english:"Cisco ASA WebVPN CIFS Share Enumeration DoS (CSCuj83344)");
  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 banner, the version of the remote Cisco ASA device is
affected by a denial of service vulnerability in the WebVPN CIFS
(Common Internet File System) access function due to missing bounds
checks on received responses when enumerating large amounts of shares
on a CIFS server. A remote, authenticated attacker can exploit this
issue by attempting to list the shares of a CIFS server with a large
amount of shares.");
  # https://tools.cisco.com/security/center/viewAlert.x?alertId=34921
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?66327426");
  script_set_attribute(attribute:"see_also", value:"https://tools.cisco.com/security/center/viewAlert.x?alertId=34921");
  script_set_attribute(attribute:"solution", value:"Apply the relevant patch referenced in Cisco bug ID CSCuj83344.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:S/C:N/I:N/A:C");
  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:"exploit_available", value:"false");

  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:"vuln_publication_date", value:"2014/07/11");
  script_set_attribute(attribute:"patch_publication_date", value:"2014/07/22");
  script_set_attribute(attribute:"plugin_publication_date", value:"2014/08/28");

  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2014-2018 Tenable Network Security, Inc.");
  script_family(english:"CISCO");

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

  exit(0);
}

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

asa   = get_kb_item_or_exit('Host/Cisco/ASA');
model = get_kb_item_or_exit('Host/Cisco/ASA/model');

ver = extract_asa_version(asa);
if (isnull(ver)) audit(AUDIT_FN_FAIL, 'extract_asa_version');

if (model !~ '^55[0-9][0-9](|-)X($|[^0-9])') audit(AUDIT_HOST_NOT, 'ASA 5500-X series');

fixed_ver = NULL;

if (ver =~ "^8\.4[^0-9]" && check_asa_release(version:ver, patched:"8.4(7.8)"))
  fixed_ver = "8.4(7)8";

else if (ver =~ "^9\.0[^0-9]" && check_asa_release(version:ver, patched:"9.0(4.2)"))
  fixed_ver = "9.0(4)2";

else
  audit(AUDIT_INST_VER_NOT_VULN, "Cisco ASA software", ver);

override = FALSE;

# Check if CIFS is enabled
if (get_kb_item("Host/local_checks_enabled"))
{
  flag = FALSE;

  buf = cisco_command_kb_item("Host/Cisco/Config/show_running-config", "show running-config");
  if (check_cisco_result(buf))
  {
    if (preg(multiline:TRUE, pattern:"^\s+nbns-server ", string:buf)) flag = TRUE;
  }
  else if (cisco_needs_enable(buf)) override = TRUE;

  if (!flag && !override) audit(AUDIT_HOST_NOT, "affected because CIFS does not appear to be enabled.");
}

if (report_verbosity > 0)
{
  report =
    '\n  Installed version : ' + ver +
    '\n  Fixed version     : ' + fixed_ver +
    '\n';
  security_warning(port:0, extra:report+cisco_caveat(override));
}
else security_warning(port:0, extra:cisco_caveat(override));