Scientists have published a paper today detailing a new Spectre-class CPU attack that can be carried out via network connections and does not require the attacker to host code on a targeted machine.
This new attack —codenamed NetSpectre— is a major evolution for Spectre attacks, which until now have required the attacker to trick a victim into downloading and running malicious code on his machine, or at least accessing a website that runs
malicious JavaScript in the user's browser.
But with NetSpectre, an attacker can simply bombard a computer's network ports and achieve the same results.
NetSpectre has low exfiltration speeds
Although the attack is innovative, NetSpectre also has its downsides (or positive side, depending on what part of the academics/users barricade you are). The biggest is the attack's woefully slow exfiltration speed, which is 15 bits/hour for attacks carried out via a network connection and targeting data stored in the CPU's cache.
Academics achieved higher exfiltration speeds —of up to 60 bits/hour— with a variation of NetSpectre that targeted data processed via a CPU's AVX2 module, specific to Intel CPUs.
Nonetheless, both NetSpectre variations are too slow to be considered valuable for an attacker. This makes NetSpectre just a theoretical threat, and not something that users and companies should be planning for with immediate urgency. But as we've seen in the past with Rowhammer attacks, as academics spend more time probing a topic, exfiltration speeds will also eventually go up, while the technical limitations that prevent such attack from working will slowly go down and dissipate.
