Guilty Minds

52

About an hour later I was back at the hotel. The dining table was covered with electronic equipment — cables and wires and little black boxes and white plastic cards and such. I set down the briefcase I’d brought into Norcross and McKenna.

“How’d it go?” Dorothy asked.

I shrugged. “Fine.”

“No problem?”

“No problem.”

“You get the briefcase close enough to a keycard?”

“I think so.”

“Let’s see what you got.”

The day before, Mandy had made her own undercover visit to the same law firm.

She’d entered the building where the firm was located with the morning rush, tailgating on someone who was entering. She took the elevator to the fourth floor and briefly stood outside the firm’s glass doors and took pictures with her smartphone, as subtly as she could, of the little black box mounted on the wall next to the glass doors.

Then she went right in to the firm’s offices and told the receptionist that she lived just down the street and was looking for temp work, and asked what agency they used to hire their temps. She spun a story about having a young child at home and needing to find work in the neighborhood. The receptionist gave her the name of an employment agency but apologized that there was nothing available at the time, so far as she knew. Mandy thanked her, and that was that.

Now Dorothy examined the photos on Mandy’s phone.

“Okay,” she said, “this is good. They’re using an HID system like just about everyone else uses. Almost certainly a low frequency 125 kilohertz system. Like eighty percent of the keycard users in the world.”

“Why is this good?” I asked. When it comes to technology, I long ago stopped worrying about sounding stupid. I ask, and Dorothy explains. This kind of technology is her forte. She enjoys being smarter than me, and I don’t mind it a bit.

“Because a couple years ago there was an interesting talk at Black Hat USA about how to defeat it.”

“How involved is this? You think we should bring in Merlin?”

Merlin’s real name was Walter McGeorge, an old army buddy who’d been a commo sergeant on my Special Forces team and later became a TSCM specialist, an expert in technical surveillance. He lived in the area, in Maryland. When I lived in DC I used to bring him in frequently to help me on jobs.

“You don’t need Merlin for this,” she said. “I promise. I can set it all up for you myself. Plug-and-play. Easy.” She tapped at her laptop. “Here we go.” She turned her laptop’s display toward me. It was an eBay page with a lot of listings, pictures of what looked like square boxes.

I recognized them. They were proximity readers, also known as badge readers. They’ve become ubiquitous in the corporate world. They’re the little black boxes mounted next to office doors at which you wave your plastic keycard to gain entry. You also see bigger versions of prox readers at the entrances and exits to parking garages. They allow drivers who have the right keycard to pass right through.

“I know what a prox reader is,” I said, “but I don’t see how that gets us in.”

“Okay. I buy one of these long-range RFID readers and do a trivial amount of futzing around to weaponize it. Stick in a PCB, a circuit board, and twelve double-A batteries. Like that. This thing can read a badge from three feet away, normally. So pay a visit to Norcross and McKenna, and you bring it in, in a backpack or briefcase, and just make sure to be within three feet of someone who’s got a badge around her neck or on his belt.”

“Then what?”

“You don’t need to know how it works. It’ll read any Wiegand protocol card that gets close enough. It captures the data on the keycard. When you get back here, I download the data and write it to a blank keycard, and that’s all she wrote. We’ve cloned the key to their front door.”

“Hold on,” I said. “Those things beep when they read a card. Am I going to be beeping audibly whenever I get near someone’s keycard?”

She smiled. “You do think ahead. Good question, and thanks for mentioning it.”

I shrugged. “Just another accidental flash of brilliance.”

“I’ll toggle a dipswitch in the thing to turn off the beep sound. Anything else?”

“Foolproof?”

“Well, idiot-proof. You should be okay.”

She placed an order through eBay with a company in South Carolina and one in Eagle Mountain, Utah, and requested overnight shipping, and the next day several large boxes arrived at the hotel, and we were in business.