What type of attacks are there that do not use open TCP or open UDP ports?

This is way too general of a question. I'm answering this very literally, not to be a jerk, but because in security it's best to assume nothing. Here are some classes of attacks that do not use open TCP or UDP ports:

• Social engineering: get someone to connect outbound from the machine to an attack site (or attach a thumb drive or bad media)
• Physical access, keyloggers, etc
• An attack at the IP level (IP stack vulnerabilities)
• NTP: usually turned on by default and might not be bug-free
• DHCP: is dhcp turned off? an attacker on the local net could push a PXE boot image to your ethernet card and load their OS.

Is it safe to assume that no open ports means no remote access?

• Drive-by downloads that get executed could call out (including pinging out bound and getting ctrl data via ping reply)
• Package managers could pull down trojaned software setting up call-out malware
• Bluetooth access

I think your real question should be: "What kinds of remote exploits can be used to root my machine if it has no open TCP or UDP ports?"

Attacks can me any number of things to people including Van Eck Phreaking.

What type of attacks are there that do not use open TCP or open UDP ports?

This is way too general of a question. I'm answering this very literally, not to be a jerk, but because in security it's best to assume nothing. Here are some classes of attacks that do not use open TCP or UDP ports:

• Social engineering: get someone to connect outbound from the machine to an attack site (or attach a thumb drive or bad media)
• Physical access, keyloggers, etc
• An attack at the IP level (IP stack vulnerabilities)
• NTP: usually turned on by default and might not be bug-free
• DHCP: is dhcp turned off? an attacker on the local net could push a PXE boot image to your ethernet card and load their OS.

Is it safe to assume that no open ports means no remote access?

• Drive-by downloads that get executed could call out (including pinging out bound and getting ctrl data via ping reply)
• Package managers could pull down trojaned software setting up call-out malware
• Bluetooth access

I think your real question should be: "What kinds of remote exploits can be used to root my machine if it has no open TCP or UDP ports?"

Attacks can mean any number of things to people including Van Eck Phreaking.