Spectre, Meltdown, & the CLIMB Exploit: A Primer on Vulnerabilities, Exploits, & Payloads
In light of the publicity, panic, and lingering despair around Spectre and Meltdown, I thought this might be a good time to clear up the differences between vulnerabilities, exploits, and malware. Neither Spectre nor Meltdown are exploits or malware. They are vulnerabilities. Vulnerabilities don’t hurt people, exploits and malware do. To understand this distinction, witness the CLIMB exploit:
Frequently, when a vulnerability is exploited, the payload is malware. But the payload can be benign, or there may be no payload delivered at all. I once discovered a windows vulnerability, exploited the vulnerability, and was then able to deliver the payload. Here’s how that story goes:
It’s kind of embarrassing to admit, but one evening my wife and I went out to dinner, and upon returning, realized we had a problem. It wasn’t food poisoning. We were locked out of our house. The solution was to find a vulnerability, exploit it, and get into the house. The vulnerability I found was an insecure window on the ground floor.
With care I was able to push the window inward and sideways to open it. From the outside, I was able to bypass the clasp that should have held the window closed. Of course, the window was vulnerable for years, but nothing bad came of it. As long as nobody used (exploited) the vulnerability to gain unauthorized access to my home, there was no harm done. The vulnerability itself was not stealing things from my home. It was just there, inert. It’s not the vulnerability itself that hurts you. It’s the payload. Granted, the vulnerability is the enabler.
The window was vulnerable for years, but nothing bad happened. Nobody attacked me, and while the potential for attack was present, an attack (exploit) is not a vulnerability. The same can be true of vulnerabilities in software. Opening the window is where the exploit comes in.
My actual exploit occurred in two stages. First, there was proof of concept (POC). After multiple attempts, I was able to prove that the vulnerable window could be opened, even when a security device was present. Next, I needed to execute the Covert Lift Intrusion Motivated Breach (CLIMB) exploit. Yeah, that means I climbed into the open window, a neat little exploit with no coding required. I suppose I could have broken the window, but I really didn’t want to brick my own house (another vulnerability?).
Now we come to the payload. In this case, the payload was opening the door for my wife. You see, not all payloads are malicious. If a burglar had used the CLIMB exploit, they could have delivered a much more harmful payload. They could have washed the dishes (they wouldn’t, unless they were Sheldon Cooper), they could have stolen electronic items, or they could have planted incriminating evidence. The roof is the limit.
Not all vulnerabilities are as easy to exploit as others. All of my second-floor windows had the same vulnerability, but exploiting them would have been more difficult. I am sure happy that I found the vulnerability before a criminal did. Because I was forgetful that fateful night, I’m also happy the vulnerability was there when I found it. As I said, I really didn’t want to break my own window. By the way, I “patched” my windows vulnerability by placing a wooden dowel between the window and the wall.
There you have it. Vulnerabilities, exploits, and payloads explained through the lens of the classic CLIMB exploit.