Fortinet Fortiweb Assessment

Fortinet FortiWeb Security Assessment

⚠️ AUTHORIZED USE ONLY — This skill is for security professionals conducting authorized assessments. Unauthorized testing may violate laws and policies.

Overview

This skill provides procedures for assessing Fortinet FortiWeb appliances for critical 2025 vulnerabilities:

Quick Assessment Workflow

1. Verify authorization — Confirm you have written permission to test the target
2. Run non-destructive probes — Check for vulnerability indicators
3. Document findings — Record version, response codes, and evidence
4. Recommend remediation — Provide patch versions and mitigations

CVE-2025-64446: Auth Bypass via API Traversal

Vulnerability Summary

FortiWeb's CGI dispatcher at /cgi-bin/fwbcgi can be reached via path traversal from API prefixes. Combined with header-based user impersonation, this allows unauthenticated admin access.

Attack Chain

1. Path traversal — Start URL with valid API prefix (/api/v2.0/cmdb/), traverse to fwbcgi
2. Input validation bypass — Send minimal JSON body {} to pass permissive check
3. User impersonation — Supply CGIINFO header with Base64-encoded identity JSON

Non-Destructive Probe

# Check if traversal is exposed (200 = vulnerable, 403 = patched)
curl -ik 'https://<target>/api/v2.0/cmdb/system/admin/../../../../../cgi-bin/fwbcgi'

Interpretation:

• HTTP 200 — Likely vulnerable, fwbcgi is accessible
• HTTP 403 — Patched, traversal blocked

Detection Indicators

• Requests to /cgi-bin/fwbcgi via paths containing ../ after /api/
• CGIINFO header with Base64 JSON containing username, loginname, vdom, profname
• Unexpected admin user creation in system logs

Mitigation

• Patch — Upgrade to 8.0.2, 7.6.5, 7.4.10, 7.2.12, or 7.0.12
• WAF rules — Block paths starting with /api/ containing ../cgi-bin/fwbcgi
• Header filtering — Reject requests with CGIINFO header
• Network segmentation — Don't expose management plane to untrusted networks

CVE-2025-25257: Fabric Connector SQLi → RCE

Vulnerability Summary

The Fabric Connector API uses the Authorization: Bearer <token> value directly in SQL queries. Attackers can inject SQL to write files, achieving code execution.

Affected Versions

• 7.6.0–7.6.3 (fixed in 7.6.4)
• 7.4.0–7.4.7 (fixed in 7.4.8)
• 7.2.0–7.2.10 (fixed in 7.2.11)
• 7.0.0–7.0.10 (fixed in 7.0.11)

Non-Destructive Probe

# Test for SQLi in Fabric Connector endpoint
curl -sk -X POST \
  -H "Authorization: Bearer ' UNION SELECT NULL,NULL,NULL,NULL INTO OUTFILE '/data/var/tmp/pwn.txt' -- -" \
  https://<target>/api/fabric/device/status

Warning: This probe attempts file creation. Use only in isolated test environments.

Detection Indicators

• Authorization headers containing SQL metacharacters (', UNION, SELECT)
• Unexpected files in /data/lib/python*/site-packages/
• Unexpected files in /data/var/waf/html/ROOT/cgi-bin/
• Hits to /api/fabric/device/status from internet IPs

Mitigation

• Patch — Upgrade to 7.6.4, 7.4.8, 7.2.11, or 7.0.11
• Input validation — Reject Authorization headers with SQL metacharacters
• File monitoring — Alert on new files in Python site-packages or CGI directories

CVE-2025-59719: FortiCloud SSO Signature Bypass

Vulnerability Summary

Improper SAML signature verification allows attackers to forge FortiCloud SSO responses and log in as admin without credentials.

Prerequisites

• FortiCloud SSO login must be enabled (auto-enabled if appliance registered via GUI)

Affected Versions

• 8.0.0 (fixed in 8.0.1)
• 7.6.0–7.6.4 (fixed in 7.6.5)
• 7.4.0–7.4.9 (fixed in 7.4.10)

Detection Indicators

• Unexpected SAML issuers in /var/log/ssod
• Unexpected SAML audience values
• Admin logins without corresponding authentication events

Mitigation

• Patch — Upgrade to 8.0.1, 7.6.5, or 7.4.10
• Disable FortiCloud SSO — If not needed, disable in GUI
• Block SAML endpoints — Don't expose SAML endpoints to internet if unused

CVE-2025-58034: OS Command Injection

Vulnerability Summary

Management plane endpoints execute user-supplied input as shell commands.

Affected Versions

• 7.0.0–7.0.11 (fixed in 7.0.12)
• 7.2.0–7.2.11 (fixed in 7.2.12)
• 7.4.0–7.4.10 (fixed in 7.4.11)
• 7.6.0–7.6.5 (fixed in 7.6.6)
• 8.0.0–8.0.1 (fixed in 8.0.2)

Non-Destructive Probe

# Send parameter with shell metacharacters, watch for 500 with command output
curl -sk 'https://<target>/api/v2.0/cmdb/system/admin?test=;id;'

Warning: If command output appears in response, block immediately and patch.

Mitigation

• Patch — Upgrade to 7.0.12, 7.2.12, 7.4.11, 7.6.6, or 8.0.2
• Input sanitization — Reject parameters containing shell metacharacters
• Network controls — Restrict management plane access

Assessment Reporting Template

## FortiWeb Security Assessment Report

### Target Information
- Host: <target>
- IP: <ip>
- Version: <detected version>
- Assessment Date: <date>
- Assessor: <name>

### Findings

#### CVE-2025-64446 (Auth Bypass)
- Status: [Vulnerable / Patched / Unknown]
- Evidence: <response code, logs>
- Risk: Critical
- Recommendation: Upgrade to <patch version>

#### CVE-2025-25257 (SQLi → RCE)
- Status: [Vulnerable / Patched / Unknown]
- Evidence: <response, file artifacts>
- Risk: Critical
- Recommendation: Upgrade to <patch version>

#### CVE-2025-59719 (SSO Bypass)
- Status: [Vulnerable / Patched / N/A - SSO disabled]
- Evidence: <SAML logs, login events>
- Risk: High
- Recommendation: Upgrade to <patch version> or disable SSO

#### CVE-2025-58034 (Command Injection)
- Status: [Vulnerable / Patched / Unknown]
- Evidence: <response output>
- Risk: Critical
- Recommendation: Upgrade to <patch version>

### Overall Risk Assessment
<Summary of findings and priority remediation steps>

References

• watchTowr Labs — FortiWeb Auth Bypass
• watchTowr vs FortiWeb — Detection Generator
• CVE-2025-25257 PoC
• FortiCloud SSO Bypass Overview
• Fortinet PSIRT Advisory FG-IR-25-910

Authorization Checklist

Before using this skill, confirm:

• Written authorization from system owner
• Scope clearly defined (hosts, tests, timing)
• Emergency contact established
• Backup/recovery plan in place
• Legal/compliance review completed

Unauthorized testing is illegal and unethical.