CyberSecBulletin
CVE-2022-43947NVD status: Modified

FortiOS: Improper Restriction of Excessive Authentication Attempts

Published Updated By the CyberSecBulletin desk

CVE-2022-43947 is a high-severity improper restriction of excessive authentication attempts vulnerability in FortiOS from Fortinet, with a CVSS 3.1 base score of 8.8 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 FortiOS versions: 7.2.0 through 7.2.3; 7.0.0 through 7.0.10; 6.4.0 through 6.4.12, 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 0.4% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Check which version of FortiOS you run against the affected versions below, and install the vendor's latest release.
  2. Read the advisory on fortiguard.com for workarounds and exact fixed builds.

Affected products and versions

VendorProductAffected versionsFixed in
FortinetFortiOS7.2.0 through 7.2.3; 7.0.0 through 7.0.10; 6.4.0 through 6.4.12; 6.2.0 through 6.2.13Not stated
FortinetFortiProxy7.2.0 through 7.2.1; 7.0.0 through 7.0.7; 2.0.0 through 2.0.12; 1.2.0 through 1.2.13; 1.1.0 through 1.1.6; 1.0.0 through 1.0.7Not 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
HighThe component can be taken down completely.

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

Scoring systemScoreSeverityScored by
CVSS 3.15.0MediumCNA (fortinet.com)
CVSS 3.18.8HighNVD

Official description

An improper restriction of excessive authentication attempts vulnerability [CWE-307] in Fortinet FortiOS version 7.2.0 through 7.2.3 and before 7.0.10, FortiProxy version 7.2.0 through 7.2.2 and before 7.0.8 administrative interface allows an attacker with a valid user account to perform brute-force attacks on other user accounts via injecting valid login sessions.

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

The underlying weakness: Improper Restriction of Excessive Authentication Attempts

The product does not implement sufficient measures to prevent multiple failed authentication attempts within a short time frame.

How developers prevent this class of flaw

  • Common protection mechanisms include: Disconnecting the user after a small number of failed attempts Implementing a timeout Locking out a targeted account Requiring a computational task on the user's part.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Consider using libraries with authentication capabilities such as OpenSSL or the ESAPI Authenticator.

More Improper Restriction of Excessive Authentication Attempts vulnerabilities (CWE-307)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in FortiOS

All FortiOS vulnerabilities

Recent Improper Restriction of Excessive Authentication Attempts vulnerabilities

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