Vulnerabilities > CVE-2005-1020 - Improper Authentication vulnerability in Cisco IOS

047910
CVSS 7.1 - HIGH
Attack vector
NETWORK
Attack complexity
MEDIUM
Privileges required
NONE
Confidentiality impact
NONE
Integrity impact
NONE
Availability impact
COMPLETE
network
cisco
CWE-287
nessus
NVD
Published: 2005-05-02
Updated: 2017-10-11

Summary

Secure Shell (SSH) 2 in Cisco IOS 12.0 through 12.3 allows remote attackers to cause a denial of service (device reload) (1) via a username that contains a domain name when using a TACACS+ server to authenticate, (2) when a new SSH session is in the login phase and a currently logged in user issues a send command, or (3) when IOS is logging messages and an SSH session is terminated while the server is sending data.

Vulnerable Configurations

Part Description Count
OS
Cisco
337

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Authentication Abuse
    An attacker obtains unauthorized access to an application, service or device either through knowledge of the inherent weaknesses of an authentication mechanism, or by exploiting a flaw in the authentication scheme's implementation. In such an attack an authentication mechanism is functioning but a carefully controlled sequence of events causes the mechanism to grant access to the attacker. This attack may exploit assumptions made by the target's authentication procedures, such as assumptions regarding trust relationships or assumptions regarding the generation of secret values. This attack differs from Authentication Bypass attacks in that Authentication Abuse allows the attacker to be certified as a valid user through illegitimate means, while Authentication Bypass allows the user to access protected material without ever being certified as an authenticated user. This attack does not rely on prior sessions established by successfully authenticating users, as relied upon for the "Exploitation of Session Variables, Resource IDs and other Trusted Credentials" attack patterns.
  • Exploiting Trust in Client (aka Make the Client Invisible)
    An attack of this type exploits a programs' vulnerabilities in client/server communication channel authentication and data integrity. It leverages the implicit trust a server places in the client, or more importantly, that which the server believes is the client. An attacker executes this type of attack by placing themselves in the communication channel between client and server such that communication directly to the server is possible where the server believes it is communicating only with a valid client. There are numerous variations of this type of attack.
  • Utilizing REST's Trust in the System Resource to Register Man in the Middle
    This attack utilizes a REST(REpresentational State Transfer)-style applications' trust in the system resources and environment to place man in the middle once SSL is terminated. Rest applications premise is that they leverage existing infrastructure to deliver web services functionality. An example of this is a Rest application that uses HTTP Get methods and receives a HTTP response with an XML document. These Rest style web services are deployed on existing infrastructure such as Apache and IIS web servers with no SOAP stack required. Unfortunately from a security standpoint, there frequently is no interoperable identity security mechanism deployed, so Rest developers often fall back to SSL to deliver security. In large data centers, SSL is typically terminated at the edge of the network - at the firewall, load balancer, or router. Once the SSL is terminated the HTTP request is in the clear (unless developers have hashed or encrypted the values, but this is rare). The attacker can utilize a sniffer such as Wireshark to snapshot the credentials, such as username and password that are passed in the clear once SSL is terminated. Once the attacker gathers these credentials, they can submit requests to the web service provider just as authorized user do. There is not typically an authentication on the client side, beyond what is passed in the request itself so once this is compromised, then this is generally sufficient to compromise the service's authentication scheme.
  • Man in the Middle Attack
    This type of attack targets the communication between two components (typically client and server). The attacker places himself in the communication channel between the two components. Whenever one component attempts to communicate with the other (data flow, authentication challenges, etc.), the data first goes to the attacker, who has the opportunity to observe or alter it, and it is then passed on to the other component as if it was never intercepted. This interposition is transparent leaving the two compromised components unaware of the potential corruption or leakage of their communications. The potential for Man-in-the-Middle attacks yields an implicit lack of trust in communication or identify between two components.

Nessus

  • NASL familyCISCO
    NASL idCSCED65778.NASL
    descriptionThe remote version of IOS has the ability to enable an SSH server to let the administrators connect to the remote device. There is an implementation flaw in the remote version of this software which may allow an attacker to cause a resource starvation on the remote device, thus preventing it from routing properly.
    last seen2020-06-01
    modified2020-06-02
    plugin id17988
    published2005-04-06
    reporterThis script is Copyright (C) 2005-2018 Tenable Network Security, Inc.
    sourcehttps://www.tenable.com/plugins/nessus/17988
    titleCisco IOS Secure Shell Server TACACS+ Multiple DoS (CSCed65778, CSCed65285)
    code
    #
# (C) Tenable Network Security
#


include("compat.inc");

if(description)
{
 script_id(17988);
 script_cve_id("CVE-2005-1020", "CVE-2005-1021");
 script_bugtraq_id(13042, 13043);
 script_version("1.24");

 script_name(english:"Cisco IOS Secure Shell Server TACACS+ Multiple DoS (CSCed65778, CSCed65285)"); 

 script_set_attribute(attribute:"synopsis", value:
"The remote device is missing a vendor-supplied security patch." );
 script_set_attribute(attribute:"description", value:
"The remote version of IOS has the ability to enable an SSH server to let
the administrators connect to the remote device.

There is an implementation flaw in the remote version of this software
which may allow an attacker to cause a resource starvation on the remote
device, thus preventing it from routing properly." );
 script_set_attribute(attribute:"solution", value:
"http://www.nessus.org/u?6f0e5315" );
 script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/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_cwe_id(287, 399);

 script_set_attribute(attribute:"plugin_publication_date", value: "2005/04/06");
 script_set_attribute(attribute:"vuln_publication_date", value: "2005/04/06");
 script_cvs_date("Date: 2018/06/27 18:42:25");
 script_set_attribute(attribute:"plugin_type", value:"local");
 script_set_attribute(attribute:"cpe", value: "cpe:/o:cisco:ios");
 script_end_attributes();


 summary["english"] = "Uses SNMP to determine if a flaw is present";
 script_summary(english:summary["english"]);

 script_category(ACT_GATHER_INFO);

 script_copyright(english:"This script is Copyright (C) 2005-2018 Tenable Network Security, Inc.");

 script_family(english:"CISCO");

 script_dependencie("snmp_sysDesc.nasl", "snmp_cisco_type.nasl");
 script_require_keys("SNMP/community", "SNMP/sysDesc", "CISCO/model");
 exit(0);
}


include('cisco_func.inc');

os = get_kb_item("SNMP/sysDesc"); if(!os)exit(0);
hardware = get_kb_item("CISCO/model"); if(!hardware)exit(0);
version = extract_version(os);
if ( ! version ) exit(0);


# 12.0 
if ( check_release(version:version, 
		   patched:make_list("12.0(26)S5", "12.0(27)S4", "12.0(28)S2", "12.0(30)S"),
		   newest:"12.0(30)S") ) vuln ++;

if ( check_release(version:version, 
		   patched:make_list("12.0(30)SX"),
		   newest:"12.0(30)SX") ) vuln ++;


if ( deprecated_version(version, "12.1AX", "12.1AZ", "12.1DB", "12.1DC", "12.1EC","12.1EU", "12.1EW", "12.1EX", "12.1T", "12.1XD", "12.1XE", "12.1XF", "12.1XG", "12.1XH", " 12.1XI", "12.1XL", "12.1XM,", "12.1XP", "12.1XQ", "12.1XR", "12.1XT", "12.1XU", "12.1XV", "12.1YA", "12.1YB", "12.1YC", "12.1YD", "12.1YE", "12.1YF", "12.1YH", "12.1YI") ) vuln ++;

if ( check_release(version:version, 
		   patched:make_list("12.1(23)E"),
		   newest:"12.1(23)E") ) vuln ++;

if ( check_release(version:version, 
		   patched:make_list("12.1(22)EA1"),
		   newest:"12.1(22)EA1") ) vuln ++;

if ( check_release(version:version, 
		   patched:make_list("12.1(23)EB"),
		   newest:"12.1(23)EB") ) vuln ++;


if ( deprecated_version(version, "12.2B", "12.2DD", "12.2DX", "12.2SU", "12.2SY", "12.2SX", "12.2XA", "12.2XC", "12.2XF", "12.2XN", "12.2XS", "12.2YE", "12.2YK", "12.2YO", "12.2YX", "12.2YZ", "12.2ZA") ) vuln ++;

if ( check_release(version:version, 
		   patched:make_list("12.2(26)"),
		   newest:"12.2(26)") ) vuln ++;

if ( check_release(version:version, 
		   patched:make_list("12.2(20)EU"),
		   newest:"12.2(20)EU") ) vuln ++;

if ( check_release(version:version, 
		   patched:make_list("12.2(40)EX1"),
		   newest:"12.2(40)EX1") ) vuln ++;

if ( check_release(version:version, 
		   patched:make_list("12.2(18)EW2", "12.2(25)EW"),
		   newest:"12.2(25)EW") ) vuln ++;

if ( check_release(version:version, 
		   patched:make_list("12.2(14)S13", "12.2(18)S7", "12.2(20)S7", "12.2(25)S"),
		   newest:"12.2(25)S") ) vuln ++;

if ( check_release(version:version, 
		   patched:make_list("12.2(20)SE4", "12.2(25)SE"),
		   newest:"12.2(25)SE") ) vuln ++;


if ( "SEA" >< version &&
     check_release(version:version, 
		   patched:make_list("12.2(25)SEA"),
		   newest:"12.2(25)SEA") ) vuln ++;

if ( "SEB" >< version &&
     check_release(version:version, 
		   patched:make_list("12.2(25)SEB"),
		   newest:"12.2(25)SEB") ) vuln ++;

if ( check_release(version:version, 
		   patched:make_list("12.2(24)SV"),
		   newest:"12.2(24)SV") ) vuln ++;

if ( "SXB" >< version &&
     check_release(version:version, 
		   patched:make_list("12.2(17d)SXB"),
		   newest:"12.2(17d)SXB") ) vuln ++;

if ( "SXD" >< version &&
     check_release(version:version, 
		   patched:make_list("12.2(18)SXD"),
		   newest:"12.2(18)SXD") ) vuln ++;

if ( check_release(version:version, 
		   patched:make_list("12.2(13)T"),
		   newest:"12.2(13)T") ) vuln ++;



if ( deprecated_version(version, "12.3XD", "12.3XE", "12.3XF", "12.3XG", "12.3XH", "12.3XJ", "12.3XK") ) vuln ++;

if ( check_release(version:version, 
		   patched:make_list("12.3(4)T11", "12.3(7)T7", "12.3(8)T"),
		   newest:"12.3(8)T") ) vuln ++;

if ( check_release(version:version, 
		   patched:make_list("12.3(7)XI3"),
		   newest:"12.3(7)XI3") ) vuln ++;

if ( check_release(version:version, 
		   patched:make_list("12.3(11)XL"),
		   newest:"12.3(11)XL") ) vuln ++;

if ( check_release(version:version, 
		   patched:make_list("12.3(7)XM"),
		   newest:"12.3(7)XM") ) vuln ++;

if ( check_release(version:version, 
		   patched:make_list("12.3(4)XQ1"),
		   newest:"12.3(4)XQ1") ) vuln ++;

if ( check_release(version:version, 
		   patched:make_list("12.3(7)XR"),
		   newest:"12.3(7)XR") ) vuln ++;

if ( check_release(version:version, 
		   patched:make_list("12.3(7)XS"),
		   newest:"12.3(7)XS") ) vuln ++;

if ( check_release(version:version, 
		   patched:make_list("12.3(8)XU"),
		   newest:"12.3(8)XU") ) vuln ++;

if ( check_release(version:version, 
		   patched:make_list("12.3(8)XW"),
		   newest:"12.3(8)XW") ) vuln ++;

if ( check_release(version:version, 
		   patched:make_list("12.3(8)XX"),
		   newest:"12.3(8)XX") ) vuln ++;

if ( check_release(version:version, 
		   patched:make_list("12.3(8)XY"),
		   newest:"12.3(8)XY") ) vuln ++;

if ( check_release(version:version, 
		   patched:make_list("12.3(8)YA"),
		   newest:"12.3(8)YA") ) vuln ++;

if ( check_release(version:version, 
		   patched:make_list("12.3(8)YD"),
		   newest:"12.3(8)YD") ) vuln ++;

if ( check_release(version:version, 
		   patched:make_list("12.3(11)YF"),
		   newest:"12.3(11)YF") ) vuln ++;

if ( check_release(version:version, 
		   patched:make_list("12.3(8)YG"),
		   newest:"12.3(8)YG") ) vuln ++;

if ( check_release(version:version, 
		   patched:make_list("12.3(8)YH"),
		   newest:"12.3(8)YH") ) vuln ++;

if ( check_release(version:version, 
		   patched:make_list("12.3(11)YJ"),
		   newest:"12.3(11)YJ") ) vuln ++;

if ( check_release(version:version, 
		   patched:make_list("12.3(11)YK"),
		   newest:"12.3(11)YK") ) vuln ++;

if ( vuln == 1 ) security_hole(port:161, proto:"udp");
else if ( vuln > 1 )  display("IOS version ", version, " identified as vulnerable by multiple checks\n");
  • NASL familyCISCO
    NASL idCISCO-SA-20050406-SSHHTTP.NASL
    descriptionCertain release trains of Cisco Internetwork Operating System (IOS), when configured to use the IOS Secure Shell (SSH) server in combination with Terminal Access Controller Access Control System Plus (TACACS+) as a means to perform remote management tasks on IOS devices, may contain two vulnerabilities that can potentially cause IOS devices to exhaust resources and reload. Repeated exploitation of these vulnerabilities can result in a denial of service (DoS) condition. Use of SSH with other authentication methods like Remote Authentication Dial In User Service (RADIUS) and the local user database may also be affected.
    last seen2019-10-28
    modified2010-09-01
    plugin id48983
    published2010-09-01
    reporterThis script is (C) 2010-2018 Tenable Network Security, Inc.
    sourcehttps://www.tenable.com/plugins/nessus/48983
    titleVulnerabilities in Cisco IOS Secure Shell Server - Cisco Systems

Oval

accepted2008-09-08T04:00:24.767-04:00
classvulnerability
contributors
nameYuzheng Zhou
organizationHewlett-Packard
descriptionSecure Shell (SSH) 2 in Cisco IOS 12.0 through 12.3 allows remote attackers to cause a denial of service (device reload) (1) via a username that contains a domain name when using a TACACS+ server to authenticate, (2) when a new SSH session is in the login phase and a currently logged in user issues a send command, or (3) when IOS is logging messages and an SSH session is terminated while the server is sending data.
familyios
idoval:org.mitre.oval:def:5455
statusaccepted
submitted2008-05-26T11:06:36.000-04:00
titleCisco Systems IOS SSH2 DoS Vulnerability
version3

References