Sylpheed is a lightweight GUI client; hardening focuses on secure account config and content handling.
¶ Account and Transport Security
- Use TLS for all mail protocols and enforce certificate validation.
- Keep account credentials protected in local profile storage.
- Use app-specific passwords when available.
- Disable automatic remote content rendering in messages.
- Scan and verify attachments before opening.
- Keep Sylpheed and related libraries updated.
- Limit desktop user access to profile directories.
- Back up profile data securely if stored locally.
- Audit account settings after server-side policy changes.