Vulnerabilities > CVE-2019-1937 - Improper Authentication vulnerability in Cisco products

047910
CVSS 9.8 - CRITICAL
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
HIGH
Integrity impact
HIGH
Availability impact
HIGH
network
low complexity
cisco
CWE-287
critical
nessus
metasploit
NVD
Published: 2019-08-21
Updated: 2023-07-17

Summary

A vulnerability in the web-based management interface of Cisco Integrated Management Controller (IMC) Supervisor, Cisco UCS Director, and Cisco UCS Director Express for Big Data could allow an unauthenticated, remote attacker to acquire a valid session token with administrator privileges, bypassing user authentication. The vulnerability is due to insufficient request header validation during the authentication process. An attacker could exploit this vulnerability by sending a series of malicious requests to an affected device. An exploit could allow the attacker to use the acquired session token to gain full administrator access to the affected device.

Vulnerable Configurations

Part Description Count
Application
Cisco
12

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.

Metasploit

descriptionThe Cisco UCS Director virtual appliance contains two flaws that can be combined and abused by an attacker to achieve remote code execution as root. The first one, CVE-2019-1937, is an authentication bypass, that allows the attacker to authenticate as an administrator. The second one, CVE-2019-1936, is a command injection in a password change form, that allows the attacker to inject commands that will execute as root. This module combines both vulnerabilities to achieve the unauthenticated command injection as root. It has been tested with Cisco UCS Director virtual machines 6.6.0 and 6.7.0. Note that Cisco also mentions in their advisory that their IMC Supervisor and UCS Director Express are also affected by these vulnerabilities, but this module was not tested with those products.
idMSF:EXPLOIT/LINUX/HTTP/CISCO_UCS_RCE
last seen2020-06-14
modified2019-08-29
published2019-08-28
references
reporterRapid7
sourcehttps://github.com/rapid7/metasploit-framework/blob/master//modules/exploits/linux/http/cisco_ucs_rce.rb
titleCisco UCS Director Unauthenticated Remote Code Execution

Nessus

NASL familyCISCO
NASL idCISCO-SA-20190821-IMCS-UCS-AUTHBY.NASL
descriptionAccording to its self-reported version, the remote host is running a version of Cisco UCS Director that is affected by an authentication bypass vulnerability. An unauthenticated, remote attacker can exploit this to bypass authentication and execute arbitrary actions with administrative privileges.
last seen2020-06-01
modified2020-06-02
plugin id128120
published2019-08-26
reporterThis script is Copyright (C) 2019 and is owned by Tenable, Inc. or an Affiliate thereof.
sourcehttps://www.tenable.com/plugins/nessus/128120
titleCisco UCS Director Authentication Bypass (cisco-sa-20190821-imcs-ucs-authby)
code
#
# (C) Tenable Network Security, Inc.
#

include("compat.inc");

if (description)
{
  script_id(128120);
  script_version("1.4");
  script_cvs_date("Date: 2019/09/24 11:01:32");

  script_cve_id("CVE-2019-1937");
  script_xref(name:"CISCO-BUG-ID", value:"CSCvp19229");
  script_xref(name:"IAVA", value:"2019-A-0312");

  script_name(english:"Cisco UCS Director Authentication Bypass (cisco-sa-20190821-imcs-ucs-authby)");
  script_summary(english:"Checks the Cisco UCS Director version.");

  script_set_attribute(attribute:"synopsis", value:"The remote host is affected by an authentication bypass vulnerability.");
  script_set_attribute(attribute:"description", value:
"According to its self-reported version, the remote host is running a version of Cisco UCS Director that is affected by
an authentication bypass vulnerability. An unauthenticated, remote attacker can exploit this to bypass authentication
and execute arbitrary actions with administrative privileges.");
  script_set_attribute(attribute:"see_also", value:"https://tools.cisco.com/bugsearch/bug/CSCvp19229");
  # https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190821-imcs-ucs-authby
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?5315f485");
  script_set_attribute(attribute:"solution", value:
"Apply the patch or upgrade to the version recommended in Cisco bug ID CSCvp19229");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:F/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:F/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2019-1937");
  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");
  script_set_attribute(attribute:"metasploit_name", value:'Cisco UCS Director Unauthenticated Remote Code Execution');
  script_set_attribute(attribute:"exploit_framework_metasploit", value:"true");

  script_set_attribute(attribute:"plugin_type", value:"combined");

  script_set_attribute(attribute:"vuln_publication_date", value:"2019/08/21");
  script_set_attribute(attribute:"patch_publication_date", value:"2019/08/21");
  script_set_attribute(attribute:"plugin_publication_date", value:"2019/08/26");

  script_set_attribute(attribute:"cpe", value:"cpe:/a:cisco:ucs_director");
  script_set_attribute(attribute:"stig_severity", value:"II");
  script_end_attributes();

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

  script_dependencies("cisco_ucs_director_detect.nbin");
  script_require_keys("Host/Cisco/UCSDirector/version");

  exit(0);
}

include('vcf.inc');

app_info = vcf::get_app_info(app:'Cisco UCS Director', kb_ver:'Host/Cisco/UCSDirector/version');

constraints = [
  { 'min_version':'6.6.0.0', 'max_version':'6.6.1.0', 'fixed_version': '6.7.2.0'},
  { 'min_version':'6.7.0.0', 'max_version':'6.7.1.0', 'fixed_version': '6.7.2.0'}
];

vcf::check_version_and_report(app_info:app_info, constraints:constraints, severity:SECURITY_HOLE);

Packetstorm

Saint

descriptionCisco UCS Director authentication bypass and command injection
titlecisco_ucs_director_auth_bypass
typeremote

References