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Threats / Fortinet / CVE-2018-13379
CVE-2018-13379 · EUVD no mirror located · GCVE no mirror located Verified 2026-06-07

Fortinet FortiOS vulnerability

Fortinet FortiOS SSL VPN web portal contains a path traversal vulnerability allowing unauthenticated attackers to download system files via specially crafted HTTP requests.

Verdict

Today item, not a backlog item.

An unauthenticated remote attacker can exploit path traversal in the FortiOS SSL VPN portal to access and exfiltrate sensitive system files, potentially exposing credentials and configuration data used in ransomware campaigns.

CISA KEV Yes · 2021-11-033Ransomware use Flagged3EPSS 0.94473 (verify live)4
01

Is it exploitable?

— the evidence, ranked above the score
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03), flagged for known ransomware use.
CISA KEV ↗Confirmed
Probability (EPSS)
EPSS 0.94473 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
FIRST EPSS ↗High
Severity / affected
Affected: Fortinet, FortiOS. Confirm exact fixed builds in the vendor advisory.
NVD ↗Reported
Weakness (CWE)
Mapped to CWE-22 Path Traversal — weakness family: Path traversal / file.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
NVD ↗Reported
WeaknessCWE-22 · Path TraversalPath traversal / file
02

Who’s exploiting it?

— attribution turns risk into urgency
Attribution not established

No threat-actor attribution is established from the public feed for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.

03

Why it matters

— the attack path, told twice: adversary, then board
1

Front door — unauthenticated access narrative 1

Attacker
I craft HTTP requests with path traversal sequences to bypass directory restrictions on the SSL VPN portal.
Business
Attackers gain unauthorized file system access without authentication, eliminating a critical security boundary.
2

Keys to the kingdom — privilege/identity takeover narrative 2

Attacker
I download sensitive FortiOS system files including configuration and credential material from the compromised portal.
Business
Exfiltrated credentials and system configurations enable lateral movement and persistence within the victim environment.
3

Lateral reach — past segmentation narrative 3

Attacker
I use extracted credentials to establish deeper access to internal systems and deploy ransomware payloads.
Business
The organization faces operational shutdown, data encryption, and extortion demands from coordinated ransomware campaigns.
04

What to do

— defensible action
  • Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05

Coverage & confidence

— what we know, and what we don’t

Established (cited)

  • KEV listing (CISA)
  • Ransomware-use flag (CISA)
  • EPSS probability (FIRST)
  • CWE weakness mapping (NVD)
  • Catalogued by fortinet (CNA)

    • Coverage gaps — stated, not hidden

  • No EUVD / GCVE mirror in feed — single-authority dependency for the identifier.
  • EPSS & exposure are time-varying; verify live at the source.
  • Threat-actor attribution not established from feed data — absence of a name is not absence of compromise.
  • No finder/reporter credit recorded in the public CVE entry — the work behind this find is unattributed.
    • Disclosure & credit2
    Catalogued by fortinetCNA
    Credited with finding itNo finder named in the public CVE record — the work behind this find is unattributed.