Vulnerabilities > CVE-2002-1706 - Improper Verification of Cryptographic Signature vulnerability in Cisco IOS

047910
CVSS 7.5 - HIGH
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
NONE
Integrity impact
HIGH
Availability impact
NONE
network
low complexity
cisco
CWE-347
nessus
NVD
Published: 2002-12-31
Updated: 2024-11-20

Summary

Cisco IOS software 11.3 through 12.2 running on Cisco uBR7200 and uBR7100 series Universal Broadband Routers allows remote attackers to modify Data Over Cable Service Interface Specification (DOCSIS) settings via a DOCSIS file without a Message Integrity Check (MIC) signature, which is approved by the router.

Vulnerable Configurations

Part Description Count
OS
Cisco
1459
Hardware
Cisco
2

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Padding Oracle Crypto Attack
    An attacker is able to efficiently decrypt data without knowing the decryption key if a target system leaks data on whether or not a padding error happened while decrypting the ciphertext. A target system that leaks this type of information becomes the padding oracle and an attacker is able to make use of that oracle to efficiently decrypt data without knowing the decryption key by issuing on average 128*b calls to the padding oracle (where b is the number of bytes in the ciphertext block). In addition to performing decryption, an attacker is also able to produce valid ciphertexts (i.e., perform encryption) by using the padding oracle, all without knowing the encryption key. Any cryptosystem can be vulnerable to padding oracle attacks if the encrypted messages are not authenticated to ensure their validity prior to decryption, and then the information about padding error is leaked to the attacker. This attack technique may be used, for instance, to break CAPTCHA systems or decrypt/modify state information stored in client side objects (e.g., hidden fields or cookies). This attack technique is a side-channel attack on the cryptosystem that uses a data leak from an improperly implemented decryption routine to completely subvert the cryptosystem. The one bit of information that tells the attacker whether a padding error during decryption has occurred, in whatever form it comes, is sufficient for the attacker to break the cryptosystem. That bit of information can come in a form of an explicit error message about a padding error, a returned blank page, or even the server taking longer to respond (a timing attack). This attack can be launched cross domain where an attacker is able to use cross-domain information leaks to get the bits of information from the padding oracle from a target system / service with which the victim is communicating. To do so an attacker sends a request containing ciphertext to the target system. Due to the browser's same origin policy, the attacker is not able to see the response directly, but can use cross-domain information leak techniques to still get the information needed (i.e., information on whether or not a padding error has occurred). For instance, this can be done using "img" tag plus the onerror()/onload() events. The attacker's JavaScript can make web browsers to load an image on the target site, and know if the image is loaded or not. This is 1-bit information needed for the padding oracle attack to work: if the image is loaded, then it is valid padding, otherwise it is not.

Nessus

NASL familyCISCO
NASL idCISCO-SA-20020617-CMTS-MD5-BYPASSHTTP.NASL
descriptionTwo issues are described in this security advisory. The first issue involves cable modems not manufactured by Cisco that allow a configuration file to be downloaded from an interface that is not connected to the network of the cable modem\
last seen2020-06-01
modified2020-06-02
plugin id48966
published2010-09-01
reporterThis script is (C) 2010-2018 Tenable Network Security, Inc.
sourcehttps://www.tenable.com/plugins/nessus/48966
titleCable Modem Termination System Authentication Bypass - Cisco Systems
code
#
# (C) Tenable Network Security, Inc.
#
# Security advisory is (C) CISCO, Inc.
# See https://www.cisco.com/en/US/products/products_security_advisory09186a0080094e97.shtml

if (NASL_LEVEL < 3000) exit(0);

include("compat.inc");

if (description)
{
 script_id(48966);
 script_version("1.13");
 script_cve_id("CVE-2002-1706");
 script_bugtraq_id(5041);
 script_xref(name:"CISCO-BUG-ID", value:"CSCdx57688");
 script_xref(name:"CISCO-BUG-ID", value:"CSCdx72740");
 script_xref(name:"CISCO-SA", value:"cisco-sa-20020617-cmts-md5-bypass");

 script_name(english:"Cable Modem Termination System Authentication Bypass - Cisco Systems");
 script_set_attribute(attribute:"synopsis", value:
"The remote device is missing a vendor-supplied security patch" );
 script_set_attribute(attribute:"description", value:
'Two issues are described in this security advisory. 
The first issue involves cable modems not manufactured by Cisco that
allow a configuration file to be downloaded from an interface that is
not connected to the network of the cable modem\'s service provider.
This historical behavior allows an unauthorized configuration to be
downloaded to the cable modem. Cisco is providing a feature in its own
software that mitigates this vulnerability. This feature is documented
as CSCdx57688. 
The second issue concerns a vulnerability in Cisco IOS Software on
only the Cisco uBR7200 series and uBR7100 series Universal Broadband
Routers. A defect, documented as CSCdx72740, allows the creation of a
truncated, invalid configuration file that is improperly accepted as
valid by the affected routers. 
Both of these vulnerabilities have been exploited to steal service by
reconfiguring the cable modem to remove bandwidth restrictions.');
 # https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20020617-cmts-md5-bypass
 script_set_attribute(attribute:"see_also", value: "http://www.nessus.org/u?ca4de3ec");
 # https://www.cisco.com/en/US/products/products_security_advisory09186a0080094e97.shtml
 script_set_attribute(attribute:"see_also", value: "http://www.nessus.org/u?1a1e2785");
 script_set_attribute(attribute:"solution", value:
"Apply the relevant patch referenced in Cisco Security Advisory
cisco-sa-20020617-cmts-md5-bypass."
  );
 script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:P/A:N");
 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:/o:cisco:ios");
 script_set_attribute(attribute:"vuln_publication_date", value: "2002/06/17");
 script_set_attribute(attribute:"patch_publication_date", value: "2002/06/17");
 script_set_attribute(attribute:"plugin_publication_date", value: "2010/09/01");
 script_cvs_date("Date: 2018/11/15 20:50:20");

 script_end_attributes();
 script_summary(english:"Uses SNMP to determine if a flaw is present");
 script_category(ACT_GATHER_INFO);
 script_copyright(english:"This script is (C) 2010-2018 Tenable Network Security, Inc.");
 script_family(english:"CISCO");
 script_dependencie("cisco_ios_version.nasl");
 script_require_keys("Host/Cisco/IOS/Version");
 exit(0);
}
include("cisco_func.inc");

#

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

# Affected: 11.3NA
if (deprecated_version(version, "11.3NA")) {
  security_warning(port:0, extra: '\nNo updates are scheduled for 11.3NA. Upgrade to a supported version\n'); exit(0);
}
# Affected: 11.3T
if (deprecated_version(version, "11.3T")) {
  security_warning(port:0, extra: '\nNo updates are scheduled for 11.3T. Upgrade to a supported version\n'); exit(0);
}
# Affected: 11.3XA
if (deprecated_version(version, "11.3XA")) {
  security_warning(port:0, extra: '\nNo updates are scheduled for 11.3XA. Upgrade to a supported version\n'); exit(0);
}
# Affected: 12.0
if (deprecated_version(version, "12.0")) {
  security_warning(port:0, extra: '\nNo updates are scheduled for 12.0. Upgrade to a supported version\n'); exit(0);
}
# Affected: 12.0SC
if (deprecated_version(version, "12.0SC")) {
  security_warning(port:0, extra: '\nNo updates are scheduled for 12.0SC. Upgrade to a supported version\n'); exit(0);
}
# Affected: 12.0T
if (deprecated_version(version, "12.0T")) {
  security_warning(port:0, extra: '\nNo updates are scheduled for 12.0T. Upgrade to a supported version\n'); exit(0);
}
# Affected: 12.0XR
if (deprecated_version(version, "12.0XR")) {
  security_warning(port:0, extra: '\nNo updates are scheduled for 12.0XR. Upgrade to a supported version\n'); exit(0);
}
# Affected: 12.1
if (deprecated_version(version, "12.1")) {
  security_warning(port:0, extra: '\nNo updates are scheduled for 12.1. Upgrade to a supported version\n'); exit(0);
}
# Affected: 12.1CX
if (deprecated_version(version, "12.1CX")) {
  security_warning(port:0, extra: '\nNo updates are scheduled for 12.1CX. Upgrade to a supported version\n'); exit(0);
}
# Affected: 12.1EC
if (check_release(version: version,
                  patched: make_list("12.1(11b)EC1", "12.1(11.5)EC", "12.1(12)EC"))) {
 security_warning(port:0, extra: '\nUpdate to ' + patch_update + ' or later\n'); exit(0);
}
# Affected: 12.1T
if (deprecated_version(version, "12.1T")) {
  security_warning(port:0, extra: '\nNo updates are scheduled for 12.1T. Upgrade to a supported version\n'); exit(0);
}
# Affected: 12.2
if (deprecated_version(version, "12.2")) {
  security_warning(port:0, extra: '\nNo updates are scheduled for 12.2. Upgrade to a supported version\n'); exit(0);
}
# Affected: 12.2BC
if (check_release(version: version,
                  patched: make_list("12.2(8)BC1b", "12.2(8)BC2"))) {
 security_warning(port:0, extra: '\nUpdate to ' + patch_update + ' or later\n'); exit(0);
}
# Affected: 12.2T
if (deprecated_version(version, "12.2T")) {
  security_warning(port:0, extra: '\nNo updates are scheduled for 12.2T. Upgrade to a supported version\n'); exit(0);
}
# Affected: 12.2XF
if (deprecated_version(version, "12.2XF")) {
  security_warning(port:0, extra: '\nNo updates are scheduled for 12.2XF. Upgrade to a supported version\n'); exit(0);
}

exit(0, "The remote host is not affected");

References