Home/CVE/Fortinet FortiOS SSL VPN Improper Authentication Vulnerability
CVE

CVE-2020-12812

Fortinet FortiOS SSL VPN Improper Authentication Vulnerability

An improper authentication vulnerability in SSL VPN in FortiOS 6.4.0, 6.2.0 to 6.2.3, 6.0.9 and below may result in a user being able to log in successfully without being prompted for the second factor of authentication (FortiToken) if they changed the case of their username.

CRITICAL · CVSS 9.8 ⚠ CISA KEV EPSS 0.40452 Ransomware: known
Act now
  • Listed on CISA KEV (known exploited in the wild)
  • Linked to known ransomware campaigns
  • SSVC exploitation status: active
  • EPSS ≥ 0.10 - elevated exploitation probability
  • EPSS percentile: top 3% of all CVEs by exploitation likelihood
  • SSVC automatable: yes - attacks can be scripted at scale
  • CVSS base score ≥ 7.0
Sigma rules10 YARA rules0
⬢

Required Remediation

Apply updates per vendor instructions.

◆

Threat Actors Linked

1
actorScarred Manticore
⬡

Weakness Classification

CWE-178Improper Handling of Case Sensitivity
CWE-287Improper Authentication
CWE-287Improper Authentication
▤

Affected Products & Versions

3
fortinet fortios< 6.0.10
fortinet fortios>= 6.2.0 and < 6.2.4
fortinet fortiosall versions
◈

Sigma Hunt Rules

10
Exact rules name this CVE ID. Product rules name an affected product in their title. Related rules cover techniques used by actors who exploited this CVE. Showing the most relevant matches; the complete related set is on the full drill-down.
relatedcriticalAntivirus Password Dumper Detection
relatedcriticalHacktool Execution - Imphash
relatedcriticalHackTool - Rubeus Execution
relatedcriticalPotential Credential Dumping Via LSASS Process Clone
relatedcriticalWCE wceaux.dll Access
relatedcriticalHackTool - Dumpert Process Dumper Default File
▣

Scoring & Timeline

9.8
CRITICAL · CVSS v3.1 · psirt@fortinet.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD24 Jul 2020 · 11:15 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
SSVC triage · cisa-vulnrichment
Exploitation
active
Automatable
yes
Technical impact
total
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
⚑

Vendor Advisories

1
cisaKEV-CVE-2020-12812
🔗

References & Sources

2
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://fortiguard.com/psirt/FG-IR-19-283Vendor Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-12812US Government Resource
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