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7 Urgent Fixes: Fortinet SAML Auth Bypass

#devops #fortinet #security #cybersecurity

Attacks are exploiting Fortinet SAML auth bypass weaknesses to gain admin access and steal configuration files. Below is a tight, ops-friendly checklist to patch fast, reduce exposure immediately, and prove closure with evidence you can hand to leadership or auditors.

Use these steps only on systems you own or explicitly manage.

7 Urgent Fixes: Fortinet SAML Auth Bypass

1) What the Fortinet SAML auth bypass enables (why SSO is an attack surface)

FortiCloud SSO (SAML) turns your perimeter device into an identity boundary. When SAML response handling is vulnerable (improper signature verification), a forged authentication flow can translate into device admin sessions.

Why it’s dangerous: perimeter device configs often contain sensitive operational and security material:

  • admin users + trusthost rules
  • VPN settings + user mappings
  • firewall objects/routes (network topology)
  • API tokens/keys/integration secrets (environment-dependent)

Impact pattern: unauthenticated access → admin session → config export/theft → follow-on intrusion.

2) Exposure checks (affected versions + FortiCloud SSO enablement)

A) Confirm product + current firmware version

Run on the device CLI:

# FortiOS / FortiGate
get system status
get system performance status

# FortiWeb
get system status
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B) Check if FortiCloud SSO admin login is enabled (the “SSO auto-enable” gotcha)

Even if you didn’t intentionally enable SSO, registration workflows can enable FortiCloud SSO admin login. If you’re not using FortiCloud SSO for admin login, disable it immediately.

Check current setting (FortiOS/FortiProxy):

show system global | grep -f "admin-forticloud-sso-login"

# If grep isn't available, scroll output:
show system global
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Disable FortiCloud SSO admin login (recommended mitigation if unused):

config system global
    set admin-forticloud-sso-login disable
end
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C) Quick “am I in the vulnerable range?” inventory helper (Python)

Use this to flag devices for urgent action from an inventory CSV (you still need to validate real device output).

# fortinet_saml_auth_bypass_triage.py
# Input CSV columns suggested: asset, product, branch, version
# Example: fw-01,FortiOS,7.4,7.4.8

import csv
from packaging.version import Version

FIX_MIN = {
  ("FortiOS","7.6"): Version("7.6.4"),
  ("FortiOS","7.4"): Version("7.4.9"),
  ("FortiOS","7.2"): Version("7.2.12"),
  ("FortiOS","7.0"): Version("7.0.18"),
  ("FortiProxy","7.6"): Version("7.6.4"),
  ("FortiProxy","7.4"): Version("7.4.11"),
  ("FortiProxy","7.2"): Version("7.2.15"),
  ("FortiProxy","7.0"): Version("7.0.22"),
  ("FortiSwitchManager","7.2"): Version("7.2.7"),
  ("FortiSwitchManager","7.0"): Version("7.0.6"),
  ("FortiWeb","8.0"): Version("8.0.1"),
  ("FortiWeb","7.6"): Version("7.6.5"),
  ("FortiWeb","7.4"): Version("7.4.10"),
}

def needs_patch(product, branch, version):
    key = (product, branch)
    if key not in FIX_MIN:
        return None
    return Version(version) < FIX_MIN[key]

with open("fortinet_inventory.csv", newline="", encoding="utf-8") as f:
    for row in csv.DictReader(f):
        asset = row["asset"].strip()
        product = row["product"].strip()
        branch = row["branch"].strip()
        version = row["version"].strip()
        res = needs_patch(product, branch, version)
        if res is None:
            print(f"[UNKNOWN BRANCH] {asset} {product} {branch} {version}")
        elif res:
            print(f"[PATCH NOW] {asset} {product} {branch} {version}  -> >= {FIX_MIN[(product,branch)]}")
        else:
            print(f"[OK] {asset} {product} {branch} {version}")
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3) Patch plan (staged upgrades + rollback-minded operations)

A) Target fixed versions (use as your minimum secure baseline)

Use the fixed version guidance for your branch. Typical targets:

  • FortiOS: 7.6.4+ / 7.4.9+ / 7.2.12+ / 7.0.18+
  • FortiProxy: 7.6.4+ / 7.4.11+ / 7.2.15+ / 7.0.22+
  • FortiSwitchManager: 7.2.7+ / 7.0.6+
  • FortiWeb: 8.0.1+ / 7.6.5+ / 7.4.10+

B) Pre-patch checklist (fast, practical)

  • Export current config and store it securely (restricted access + encrypted storage)
  • Validate HA state and failover behavior (if applicable)
  • Confirm storage space + firmware image integrity
  • Confirm upgrade path compatibility (avoid unsupported jump upgrades)
  • Tell SOC/IR: expect log noise + possible HA events
  • Document “backout”: what triggers rollback, who approves, how you revert

Example: evidence-friendly backup naming

<site>-<device>-prepatch-YYYYMMDD.conf
<site>-<device>-postpatch-YYYYMMDD.conf
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Config backup (pattern; syntax varies by platform/version)

execute backup config flash <filename.conf>
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4) Containment while patching (reduce exposure today)

A) Restrict management interfaces (non-negotiable)

Goal: management plane reachable only from a dedicated admin network (VPN/jump host), never from “anywhere”.

Interface allowaccess hardening (example)

config system interface
    edit "wan1"
        set allowaccess ping
    next
    edit "mgmt"
        set allowaccess https ssh ping
        set ip 10.10.10.1 255.255.255.0
    next
end
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Admin trusthost allowlisting (example)

config system admin
    edit "admin"
        set trusthost1 10.10.0.0 255.255.0.0
        set trusthost2 192.168.50.0 255.255.255.0
    next
end
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Local-in policy idea (example pattern)

# Goal: allow admin services only from VPN/jump ranges
# (Exact policy syntax varies; implement per your platform guidance)
config firewall local-in-policy
    edit 1
        set intf "wan1"
        set srcaddr "Admin_VPN_Ranges"
        set service "HTTPS" "SSH"
        set action accept
    next
    edit 2
        set intf "wan1"
        set service "HTTPS" "SSH"
        set action deny
    next
end
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B) Disable FortiCloud SSO admin login if unused 

config system global
    set admin-forticloud-sso-login disable
end
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C) Reduce “config theft” blast radius

  • lock down who can export configs
  • restrict admin GUI to a dedicated interface/VLAN
  • forward admin event logs to SIEM (and verify retention)

5) Rotate credentials and secrets after patching (assume possible config exposure)

If exploitation is suspected (or you can’t confidently rule it out), rotate:

  • local admin passwords
  • VPN secrets and admin portal credentials
  • API tokens (SIEM, automation, integrations, remote management)
  • any credentials stored in device objects (deployment-dependent)

Generate a strong password (Linux/macOS)

python3 - << 'PY'
import secrets, string
alphabet = string.ascii_letters + string.digits + "-_"
print("".join(secrets.choice(alphabet) for _ in range(32)))
PY
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Generate tamper-evident hashes for your evidence pack

mkdir -p evidence/{pre,post,logs}
sha256sum evidence/**/* > evidence/HASH_MANIFEST.sha256
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6) Hunting: suspicious SSO events, config exports, new admin sessions

You’re looking for:

  1. unusual admin login events
  2. config export/download activity
  3. unexpected admin creation or policy edits

A) Quick grep triage (exported logs) 

grep -Ei "admin login|sso|saml|config.*(export|backup|download)|new admin" fortinet-events.log | tail -n 200
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B) Splunk SPL (generic) 

index=network (vendor="fortinet" OR sourcetype=fortinet*)
("admin login" OR saml OR sso OR "config" OR "backup" OR export OR download OR "new admin")
| stats count min(_time) as firstSeen max(_time) as lastSeen values(src_ip) as src values(user) as users by host
| sort - lastSeen
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C) Microsoft Sentinel KQL (generic) 

Syslog
| where SyslogMessage has_any ("forti", "fortigate", "fortiweb")
| where SyslogMessage has_any ("admin login", "sso", "saml", "config", "backup", "export", "download", "new admin")
| summarize Count=count() by Computer, bin(TimeGenerated, 1h)
| order by TimeGenerated desc
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D) Elastic KQL (generic) 

(event.dataset : "syslog" OR event.module : "fortinet")
AND message : ("admin login" OR sso OR saml OR config OR export OR backup OR download OR "new admin")
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7) Proof of closure (post-patch validation + exec-ready summary)

A) Technical validation checklist

  1. Confirm device firmware is at or above fixed version
  2. Confirm FortiCloud SSO admin login is disabled if unused
  3. Confirm management plane isn’t reachable from the internet
  4. Confirm trusthosts/local-in policies enforce allowlists
  5. Confirm admin event logging is forwarded + retained

External reachability smoke test

nmap -Pn --open -p 22,80,443,8443,9443 TARGET
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B) Executive-ready remediation summary (copy/paste)

  • Issue: Fortinet SAML auth bypass impacting FortiCloud SSO login (CVE-2025-59718 / CVE-2025-59719)
  • Business risk: Perimeter admin takeover → configuration theft → follow-on compromise
  • Scope: [list devices/products/versions]
  • Actions completed: Patched to fixed versions; restricted management plane; disabled FortiCloud SSO admin login where not required; rotated credentials/tokens; enabled monitoring
  • Validation: Version + config checks; external reachability tests; SIEM log review
  • Residual risk: [none / acceptable / follow-up required]
  • Next step: targeted configuration review + retest within 7–14 days

Where Pentest Testing Corp helps (pentest → hardening → proof)

If you want a fast, evidence-rich validation (not scan-only), we can help you:

  • confirm exposure across your perimeter estate
  • test management-plane controls (auth, session, ACLs, hardening)
  • deliver an executive-ready remediation pack + retest results

Start here:

Free Website Vulnerability Scanner Tools page

Screenshot of the free tools webpage where you can access security assessment tools.Screenshot of the free tools webpage where you can access security assessment tools.

Link: https://free.pentesttesting.com/

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