New attack uses vulnerability in microchips.

“Modern processors are fast, in part, because they guess. Rather than waiting to find out which way a program will branch, a chip predicts the likely path. And races ahead. When the guess is right. “ (MIT)

“Time is saved. When it’s wrong, the work is discarded, but traces of it linger. Since the Spectre vulnerability was disclosed in 2018, attackers have known how to read those traces to pull secrets out of memory they should never see.” (MIT)

MIT Schwarzman college of computing uncovers a new type of attack. That opens Linux passwords to an attacker. The attacker uses the vulnerability in a modern microchip log file. The microprocessor itself creates this file. Called a “guess file”. Officially, that file is called prediction machinery. But. I use the term “Guess file”. That is the log file. The microchip uses it to predict how the program routes itself. 

“AMD’s defense, called saferet, cleans the prediction machinery immediately before each use, leaving a vulnerable window just two instructions wide, which typically execute within tens of nanoseconds. The researchers hit it anyway, by slowing down the processor at that exact spot to make the target easier to strike.” (MIT)

There is one small vulnerability. The system needs to stop before it starts a new task. That opens the door to the processor. A couple of milliseconds is enough to slow the processor. The attacker can strike. We know. That hackers can exploit even the smallest windows and backdoors. They can get access to the system. Those vulnerabilities are growing bigger in the time of AI. AI can launch attacks. Using precise and fast reactions. The AI waits for the processor to slow down. Before it begins a new task. When the processor stops, the AI tries to slip malicious code into the processor. 

So the computer makes a bad guess. And that opens a path to at least the password file. 

“The defenses work by wiping or isolating the processor’s prediction machinery, removing anything an attacker might have planted. The catch, as PhD student Daniël Trujillo and MIT Assistant Professor Mengjia Yan point out, is that the wipe and the moment the predictions get used can’t happen at the same instant. There is always a gap. — sometimes only a handful of instructions wide. Anything that runs in that gap can dirty the machinery all over again. The researchers call this class of attack “TONTOU.” (MIT)

If hackers can infect microchips, they can infect an entire computer. The microchip is a small computer. There is a cache and an operating system. The Kernel is the program that connects the hardware to software. Every command that a user gives. And a program that runs on a computer travels through the processor. If malware. Can be written in the microchip. The results can be destructive. The cache is the point. There, the malware could write itself. 

If. The cache is not protected. That can cause infection. There is a small possibility that the attackers can write their malware in that memory. Normally, a microchip’s internal control programs run on ROM. But that cache is vulnerable. Researchers in an MIT laboratory created a method called “interrupt injection”. 

“To show what this means in practice, the team built a working exploit on an AMD system running a current Linux kernel. They first stripped away a defense that scrambles where the operating system sits in memory, succeeding in all 10 tries in about nine minutes each. That helped them read protected memory at roughly five bytes per second — slow, but fast enough to locate and copy “/etc/shadow,” the file storing the system’s root password hash, in half their attempts.” (MIT)

This file tells the computer which program requires attention. Normally, the processor destroys that file immediately after it uses it.  But researchers could slow the processor at a critical moment. And they could use that file to open the password file. This means. They got access to the entire system. 

But the “guess-file”. It has another option. That option is that. It determines which program or file can use the microprocessor’s resources. There is a small possibility. Tha. If hackers can create that file. And slip it into the microchips. They can gain access to the entire system. And they can slip in any malware. In a computer, using the microprocessors as the platform. 

https://computing.mit.edu/news/new-type-of-attack-can-slip-past-the-defenses-in-your-computers-processor/

https://en.wikipedia.org/wiki/Spectre_(security_vulnerability)