Moulton isolated the listing and expanded it. It looked like so much gibberish to Chapel — just line after line of numbers and strings of letters he knew he would never understand.
Hollingshead walked over to the screen. “Here.” He pointed at a line that read 10.0.0.1. “This lists the IP address for the incoming commands, yes?”
Holman nodded. “That’s right.”
Chapel tried to remember everything he’d heard Angel say about IP addresses. He knew they were pretty useful. “If you know that, you can track the command back to whoever issued it, right? You can get their physical location.”
“You might,” Holman said, “except of course the hijacker would know that. So he went to the trouble of altering the IP address on his outgoing commands. 10.0.0.1 is a default IP address — just a placeholder. It doesn’t mean anything.”
“You can do that?” Chapel asked.
“It’s actually pretty easy,” Moulton told him.
“So…” Chapel shook his head. “So we’re seeing the actual code the hijacker used to control the Predator. But that code doesn’t tell us anything useful. They’ve hidden themselves and there’s no way to find out who they are.”
“Yeah, right,” the analyst sneered. “I can totally track them. They just went to enough trouble to make it interesting.”
“The hijacker prevented us from doing this the easy way. And maybe if you were talking to anybody else, it would end there. But this is the NSA. We’ve been cracking codes since World War I.” Moulton turned around in his chair. “Whoever sent these commands, they thought they were anonymous. But you can’t ever really be anonymous on the Internet.” He glanced from one to another of them with little grunts of frustration as if trying to decide who might understand what he said next. “You leave… fingerprints, I guess, is a good analogy. I can’t get an IP address out of this code. But there’s still a path to follow.” He turned back to his keyboard. “This is going to take a few minutes.”
“Take your time,” Holman told him. “Do it right.”
Moulton nodded over his keyboard. He opened up another program, one that looked to Chapel like a giant and very, very complicated spreadsheet. He entered a mathematical equation in a field at the top of the sheet and then opened yet another program that showed a map of the world.
“I’m going to query our network analyzer. This thing’s like a packet sniffer on steroids.” He glanced around the room and then sighed. “Basically, um, I can’t just trace the signal back to its source. But because of how the Internet works, I can find everywhere the signal passed through on its way to the Predator. All the servers it touched on its way. It’s like looking for a needle in a haystack by examining every piece of hay for how long ago they were next to the needle. Then by knowing where those pieces of hay were, you can home in on where the needle was, even though it isn’t there anymore.”
“If it works,” Wilkes said, “I don’t really care how it works.”
The analyst nodded. He clicked his mouse, and up on the screen thousands of red dots appeared on the map, spread out pretty evenly. “These are all the servers the signal passed through. Somewhere in there is your hijacker.”
He clicked his mouse again and then pushed back from the workstation to watch the big screen with the rest of them. Up there, a huge number of the dots disappeared, leaving Africa and Australia completely bare.
Chapel knew he would never follow what was actually happening, so he just watched the map. It was almost hypnotic to watch the dots fall away. As more dots blinked out, the process slowed down dramatically. Long seconds would tick by before another one dropped off the map. But the program kept running. Chapel estimated they were down to only a few hundred at most. Then, suddenly, every dot disappeared from Europe and Asia, leaving only those in the United States.
“The signal came from inside the country,” Holman interpreted.
A chill ran down Chapel’s spine. He remembered what Wilkes had said back in the car — that this might be an inside job. His mouth was suddenly dry. “Are we looking at somebody military, or a civilian?” he asked.
Holman looked at him with wide eyes. “What are you suggesting?” she asked.
Chapel shook his head. “Nothing yet. Just — Moulton. What do you think?”
“Hard to say — the fact that they passed through so many servers so quickly makes me think it’s military. Or at least they’re using military-grade software.”
“Let’s not jump to conclusions yet,” Holman said.
The map changed to just show the United States. Then almost at once it changed again, to just show the northeastern corridor. One by one the dots kept going out. The map changed a third time to show the greater Washington, D.C., area, with red dots clustered around the Pentagon and Fort Belvoir.
Chapel took a deep breath. It looked like it was one of their own. The possibility had always been there. But at least now they knew, at least they could narrow down the list of possible culprits. And then Chapel could go and find the hijacker and put an end to this before things went too far. All right, that was acceptable. And he had to admit they couldn’t have done it without the NSA.
“This,” Chapel said as the lights continued to go out, “is some pretty impressive hacking.”
“Excuse me?” Moulton said.
“You’re quite the hacker,” Chapel said, smiling.
Moulton erupted out of his chair and jabbed a finger in Chapel’s face. “You take that back.”
“What? Listen, I didn’t mean—”
“I am not a hacker,” Moulton insisted. “A hacker exploits weaknesses. They break into things. I’m using tools that were designed just for this purpose.”
“I didn’t, uh — hey, let’s just—”
Hollingshead cleared his throat, quite distinctly. “Gentlemen,” he said, “if you’ll put this disagreement on hold, you might wish to look at the map.”
Chapel turned and looked at the screen. What he saw made him forget all about Moulton’s outburst.
Only one dot remained on the map. It was on the Pentagon.
Everyone in the room held their breath. They knew what that had to mean. The hijacking was an inside job. It wasn’t a debatable point anymore.
“Military, then,” Holman said, walking toward the map as if she wanted to see it more clearly. “Military. Or maybe a civilian contractor working for a military organization. Can we get any more details?”
“Sure,” Moulton said. He glared at Chapel one last time and then returned to his seat. He glanced at his monitor for a moment, then tapped a key and the view on the screen disappeared, replaced with a block of code that Chapel couldn’t read. “Here we go. The IP address you requested. It doesn’t look like the other one because this is an IPv6 address, which is … oh,” Moulton said. “Oh, this is — this is a little, um—”
“Delicate,” Holman said. “Rupert, I’m so sorry you had to find out like this, I assure you I had no idea—”
She stopped talking because Hollingshead had lifted his hands for peace. He had his eyes closed, and he looked like he was fighting to control himself.
“It’s us,” he said.
“What?” Chapel asked. “What are you saying?”
“That IP address is one reserved for use by the Defense Intelligence Agency,” Hollingshead said very quietly. “The hijacker is one of ours.”
Chapel was so stunned he had no idea what to say.
Wilkes didn’t have the same problem. “Give me a name,” he said.
Moulton did something that cleared his screen and then brought up a page of text — numbers and words, but none Chapel could make any sense out of. The IP address was highlighted in one cell near the middle of the sheet. There was no name associated with the address, just a sixteen-digit number.