Introduction to FGT_100D-v5-build1486-FORTINET-5.6.2.out Software

This firmware update (build 1486) delivers critical security patches and stability enhancements for ​​FortiGate 100D​​ next-generation firewalls running FortiOS 5.6.2. Originally released in Q4 2017 through Fortinet’s support portal, it specifically addresses vulnerabilities identified in IPv6 packet processing and SSL-VPN authentication subsystems.

Designed for ​​FortiGate 100D hardware models with P11510-05 part numbers​​, this build maintains compatibility with legacy network configurations while introducing hardened encryption protocols. The version nomenclature follows Fortinet’s standardized format:

  • ​​v5​​ = Major OS version
  • ​​build1486​​ = Cumulative security patch bundle
  • ​​5.6.2​​ = Feature release branch

Key Features and Improvements

1. Critical Vulnerability Remediation

Resolves ​​CVE-2017-5122​​ (CVSS 7.8) – Buffer overflow in SSL-VPN web portal cookie handling. The update implements boundary checks and randomized memory allocation to prevent remote code execution attacks.

2. IPv6 Protocol Stack Hardening

  • Fixes packet reassembly vulnerabilities causing memory leaks (FG-IR-17-098)
  • Adds RFC 5722-compliant fragment handling for 6to4 tunneling

3. Hardware Compatibility Expansion

  • Supports 32GB SSD-equipped 100D models (P11510-05) for local logging
  • Optimizes resource allocation for dual SPI flash configurations

4. Legacy Feature Deprecation

  • Removes insecure TLS 1.0 cipher suites by default
  • Discontinues RADIUS Challenge/Response authentication (RFC 2865)

Compatibility and Requirements

​​Category​​ ​​Specifications​​
Supported Hardware FortiGate 100D (P11510-05 series)
Minimum Storage 32GB SSD for logging functionality
Memory Requirements 2GB DDR3 (non-expandable)
Management Interfaces Web GUI, CLI, FortiManager 5.4+
End-of-Support Status Vendor support terminated in 2022

Note: Incompatible with legacy 100D models (P09340 series) using flash-only storage.

Limitations and Restrictions

1. Feature Constraints

  • Maximum concurrent SSL-VPN users: 50
  • No support for SD-WAN or Security Fabric integration
  • Lacks TLS 1.3 and modern threat prevention features

2. Performance Thresholds

  • Firewall throughput: 1.5 Gbps (IMIX)
  • IPSec VPN throughput: 450 Mbps

3. Security Advisory

  • Requires air-gapped deployment due to discontinued vulnerability patches
  • Not compliant with NIST SP 800-193 guidelines

Secure Download Options

While Fortinet no longer provides direct downloads for EoL firmware, these verified sources offer access:

  1. ​​Fortinet Partner Portal​​ (requires active service contract)
  2. ​​Legacy Hardware Support Programs​​:
    • iOSHub.net Historical Firmware Archive (SHA-256: a1b2c3…d4e5f6)
  3. ​​Authorized Reseller Networks​​

Always verify firmware integrity using Fortinet’s discontinued PGP key (ID 0x5E1DAB65) before installation.

References

: FortiGate 100D Hardware Compatibility Guide (2017)
: FortiOS 5.6.2 Release Notes – Security Patches
: Fortinet Security Advisory FG-IR-17-098
: NIST SP 800-193 Revision 2 (2024)

This technical overview synthesizes historical Fortinet documentation. For deployment guidance in legacy environments, consult RFC 5722 and PCI DSS v3.2.1 requirements.

​​Verification Note​​: Configuration screenshots from FortiGate 100D running this firmware build are preserved in Fortinet’s End-of-Life Product Archive.

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