PSIRT Advisory

FortiOS local certificate private key improper protection in admin CLI console

Summary

Improper permission or value checking in the CLI console may allow a non-privileged user to obtain plaint text private keys of system's builtin local certificates via unsetting the keys encryption password or for user uploaded local certificates via setting an empty password.

Note that backed up config files can be restored onto a version of FortiOS vulnerable to this, in order to obtain the plaintext versions of local certificates private keys encrypted in those config files.

Impact

Information Disclosure

Affected Products

For system builtin local certificates via unsetting password:

FortiOS 6.2.0, 6.0.0 to 6.0.6, 5.6.10 and below

For user uploaded local certificates via setting an empty password:

FortiOS 6.2.1, 6.2.0, 6.0.6 and below.

Solutions

For system builtin local certificates via password unset:

Upgrade to FortiOS 5.6.11, 6.0.7 or 6.2.1 and above

For user uploaded local certificates via setting empty password:

Upgrade to FortiOS 6.0.7 or 6.2.2 and above

[Workarounds]

Always encrypt your FortiGate configuration during backup and ensure to store or transfer your FortiGate configuration through secure channels.

Avoid disclosing your FortiGate config snippet containing the following parts:

config vpn certificate local
    edit [cert-name]
        set password ENC xxx
        set private-key "-----BEGIN ENCRYPTED PRIVATE KEY----- ..."
    next
end

References

• https://stuff.purdon.ca/?page_id=233