CVE-2016-1909

CRITICAL

Fortinet <5.0.12 - Hardcoded Passphrase

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 2 public exploits for CVE-2016-1909. PoCs published by operator8203, including Metasploit module auxiliary/scanner/ssh/fortinet_backdoor.

AI-analyzed exploit summary This exploit leverages a hardcoded SSH backdoor in FortiGate OS versions 4.x to 5.0.7, allowing unauthenticated access via a custom authentication handler that generates a valid password hash. It establishes an interactive shell session over SSH.

Description

Fortinet FortiAnalyzer before 5.0.12 and 5.2.x before 5.2.5; FortiSwitch 3.3.x before 3.3.3; FortiCache 3.0.x before 3.0.8; and FortiOS 4.1.x before 4.1.11, 4.2.x before 4.2.16, 4.3.x before 4.3.17 and 5.0.x before 5.0.8 have a hardcoded passphrase for the Fortimanager_Access account, which allows remote attackers to obtain administrative access via an SSH session.

Exploits (2)

exploitdb WORKING POC
by operator8203 · pythonremotelinux
https://www.exploit-db.com/exploits/43386

This exploit leverages a hardcoded SSH backdoor in FortiGate OS versions 4.x to 5.0.7, allowing unauthenticated access via a custom authentication handler that generates a valid password hash. It establishes an interactive shell session over SSH.

Classification
Working Poc 100%
Attack Type
Auth Bypass
Complexity
Trivial
Reliability
Reliable
Target: FortiGate OS versions 4.x to 5.0.7
No auth needed
Prerequisites: Network access to the target device · SSH service exposed on the target
devstral-2 · analyzed Feb 16, 2026 Full analysis →
metasploit SCANNER
rubypoc
https://github.com/rapid7/metasploit-framework/blob/master/modules/auxiliary/scanner/ssh/fortinet_backdoor.rb

This Metasploit module scans for the Fortinet SSH backdoor (CVE-2016-1909) by attempting to authenticate using the hardcoded 'Fortimanager_Access' username. It does not exploit the vulnerability but verifies its presence.

Classification
Scanner 100%
Attack Type
Auth Bypass
Complexity
Trivial
Reliability
Reliable
Target: Fortinet FortiOS (versions affected by CVE-2016-1909)
No auth needed
Prerequisites: Network access to the target's SSH port (22)
MITRE ATT&CK
devstral-2 · analyzed Feb 16, 2026 Full analysis →

References (7)

Core 7
Core References
Exploit mailing-list x_refsource_fulldisc
http://seclists.org/fulldisclosure/2016/Jan/26
Third Party Advisory, VDB Entry vdb-entry x_refsource_sectrack
http://www.securitytracker.com/id/1034663
Exploit exploit x_refsource_exploit-db
https://www.exploit-db.com/exploits/39224/

Scores

CVSS v3 9.8
EPSS 0.7127
EPSS Percentile 99.3%
Attack Vector NETWORK
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Details

CWE
CWE-264
Status published
Products (10)
fortinet/fortios 5.0
fortinet/fortios 5.0.0
fortinet/fortios 5.0.1
fortinet/fortios 5.0.2
fortinet/fortios 5.0.3
fortinet/fortios 5.0.4
fortinet/fortios 5.0.5
fortinet/fortios 5.0.6
fortinet/fortios 5.0.7
fortinet/fortios < 4.3.16
Published Jan 15, 2016
Tracked Since Feb 18, 2026