CyberSecBulletin
CVE-2023-20154NVD status: Analyzed

Cisco Modeling Labs: Authentication Bypass by Primary Weakness

CVE-2023-20154 is a high-severity authentication bypass by primary weakness vulnerability in Cisco Modeling Labs from Cisco, with a CVSS 3.1 base score of 8.1 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. Affected Cisco Modeling Labs versions: 2.3.0; 2.3.1; 2.4.0, and others listed below. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.91% chance of exploitation within 30 days, higher than 60% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Check which version of Cisco Modeling Labs you run against the affected versions below, and install the vendor's latest release.
  2. Read the advisory on sec.cloudapps.cisco.com for workarounds and exact fixed builds.

Affected products and versions

VendorProductAffected versionsFixed in
CiscoCisco Modeling Labs2.3.0; 2.3.1; 2.4.0; 2.4.1; 2.5.0Not stated
Ciscomodeling_labs2.3.0; 2.3.1; 2.4.0; 2.4.1; 2.5.0Not stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
NoneAvailability is not affected.

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.19.1CriticalCNA (cisco.com)
CVSS 3.18.1HighNVD

Official description

A vulnerability in the external authentication mechanism of Cisco Modeling Labs could allow an unauthenticated, remote attacker to access the web interface with administrative privileges. This vulnerability is due to the improper handling of certain messages that are returned by the associated external authentication server. An attacker could exploit this vulnerability by logging in to the web interface of an affected server. Under certain conditions, the authentication mechanism would be bypassed and the attacker would be logged in as an administrator. A successful exploit could allow the attacker to obtain administrative privileges on the web interface of an affected server, including the ability to access and modify every simulation and all user-created data. To exploit this vulnerability, the attacker would need valid user credentials that are stored on the associated external authentication server. Cisco has released software updates that address this vulnerability. There are workarounds that address this vulnerability.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Authentication Bypass by Primary Weakness

The authentication algorithm is sound, but the implemented mechanism can be bypassed as the result of a separate weakness that is primary to the authentication error.

More Authentication Bypass by Primary Weakness vulnerabilities (CWE-305)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Authentication Bypass by Primary Weakness vulnerabilities

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