Reborn in 2000, starting from the university website

Bai Yuhang, Zhang Jian, Wan Lianghao, and Zhang Qingheng took a taxi and sped into the New Century Internet Cafe. The cold wind they brought with them startled Wang Jun, the doorman.

The usual smell of smoke was gone from the private room; instead, there was a strong smell of sweat and anxiety.

Zhang Jian's fingers left afterimages on the keyboard, but the error logs on the screen continued to flood the screen like a waterfall, with the black words "Connection Timed Out" hurting one's eyes.

"No way! It's completely unsustainable!" Zhang Jian's voice was hoarse, as if he'd swallowed charcoal. "The CPU usage is constantly at 100%, and the memory is already full. Qihang's campus network, navigation site, and music site are all down; we can't even load a static page. It's like hundreds of thousands of requests are flooding in every second, just junk data packets, trying to clog us up!"

Bai Yuhang pulled Zhang Jian, who was covered in sweat, aside and sat down in front of the computer himself.

His fingers flew across the keyboard as he typed a few lines of commands, bringing up the server access logs. He glanced at them, and his brow furrowed deeply.

"SYN Flood attack." Bai Yuhang stared at the endless stream of fake handshake requests to the server. "This isn't a normal user access; someone has paid to rent a 'zombie' network of compromised machines to bombard our port. This tactic is designed to completely destroy Qihang."

The phone at the front desk suddenly rang, its shrill ring echoing into the deathly silent private room like a death knell.

Wang Jun, the network administrator, relayed the message. Zhang Jian walked to the front desk and answered the phone, trembling. Before he could speak, a roar came from the receiver. It was Zhang Tian, ​​a customer service representative from China Telecom.

"Where's your boss, Mr. Bai? Let him answer the phone!"

Bai Yuhang took the receiver, but before he could even bring it to his ear, Zhang Tian's voice exploded: "Dude, I can't protect you anymore! Your traffic has crashed the backbone network switches, affecting a huge amount of business. The higher-ups are furious and ordered it to be resolved within ten minutes. If it's not resolved, I'll have to physically disconnect you. Then your website IP will be a dead number on the internet, and even a god couldn't save it!"

"Brother Zhang, give me five more minutes."

"Fifteen minutes? With this data usage..."

"Just fifteen minutes. If the attack traffic doesn't decrease after fifteen minutes, you don't need to unplug it; I'll shut it down myself."

After hanging up the phone, Bai Yuhang ignored the data logs that were constantly popping up and reporting errors, and instead turned to look at Wan Lianghao, Zhang Jian, and Zhang Qingheng.

"If we don't have the money for a hardware firewall, we'll go with the software approach." Bai Yuhang spoke rapidly, but without the slightest panic. "Third brother, modify the Nginx configuration, throw all requests into the black hole route, and perform checks on all access requests. Fourth brother, extract the login part of the previous front-end homepage separately, and I'll write a login verification script to add a 'sieve' to all accesses. Seventh brother, you just watch the whole process and understand the processing logic."

"A sieve? A CAPTCHA?" Wan Lianghao was taken aback. "A simple numeric CAPTCHA can't stop this kind of botnet script attack."

"Who said we'd use numbers? Let's use plain language." Bai Yuhang's lips curled into a cold smile. "Scripts are static, but people are dynamic. I'm going to take the 'Turing Test,' and specifically, the Turing Test within our school's online community."

Five minutes later, a simple but life-saving piece of code was pushed to the front-end server.

Meanwhile, the hundreds of thousands of zombie requests that were relentlessly attacking the Startup server suddenly hit a wall. All access pages turned into a login verification pop-up, with no distorted letters, only a few questions that only Chinese netizens born in the 80s would understand.

Question 1: In the game CS, what kind of gun is the B-4-1?

A. Sniper rifle B. Submachine gun C. Dragon-slaying sword D. Whistle stick

Question 2: How many years does primary school usually last?

A. 6 years B. 100 years C. No need to go to school D. 3 years

Question 3: Xiaoming went to an internet cafe, and the owner asked him what he wanted to do. He said he wanted to "stay overnight." What time does a "stay overnight" usually end?

A. 12 midnight B. 12 noon C. 5 pm D. 8 am

"Will this... will this work?" Zhang Jian's palms were sweaty as he looked at these seemingly irrelevant questions.

"Send it up."

Press the Enter key.

A miracle happened.

The once booming traffic curve plummeted as if it had been cleaved in half. Attack scripts that only knew how to send simple packets were completely baffled by questions like "What is a B41 gun?" and were all blocked from the core servers.

The actual users, after a brief moment of surprise, were amused.

"Holy crap! Lao Liu, look!" Wan Lianghao pointed to a screenshot of the OICQ chat box. "These guys are crazy! Someone in the department sent me a screenshot of our verification interface, and they're having a race to see who can type the fastest. Someone even asked if choosing C would get them a Dragon Slayer Sword."

"This isn't a firewall, it's a joke!" Zhang Jian looked at the backend. The original attack traffic had been completely cleaned up, leaving only access requests from real users. These requests were continuously being verified, and the server load quickly dropped from 100% to a healthy 20%.

The crisis is over.

Bai Yuhang lit a cigarette, took a deep drag, and let the nicotine soothe his tense nerves.

"Investigate." He exhaled a smoke ring and pointed to all the intercepted attack sources in the log. "Now that the tide has receded, I want to see who's been swimming naked."

Without the cover of massive amounts of junk data, the attacker's control terminal IP is as conspicuous as a louse on a bald man's head.

"Found it!" Wan Lianghao traced a line on the map with his finger. "It's not an overseas IP address, it's in Harbin! Nangang District... Xuefu Road... near Harbin University of Science and Technology!"

Zhang Jian leaned over and glanced at the specific IP range, then cursed, "Isn't this a branch of 'Extreme Speed ​​Internet Cafe'? It's just across the street from the back gate of the university."

The people in the room exchanged glances, and they all understood what was going on.

Harbin University of Science and Technology is said to be a place Chen Yuan frequented after he was expelled from the university.

"Is this some kind of idiot Chen Yuan? Is he desperate?" Bai Yuhang flicked his cigarette ash, his eyes devoid of any warmth. "He has some money left but doesn't keep it for food, instead using it all to buy chickens to attack us. This Chen Yuan really doesn't want to live anymore."

"Sixth Brother, what should we do? Find someone to beat him up?" Zhang Qingheng rolled up his sleeves indignantly.

"Beat him up? No fun, that's something petty thugs do." Bai Yuhang turned to Yang Bo, who was always studying legal articles. "Have the second brother write a police report later. If I remember correctly, this is a crime of damaging a computer information system, causing system paralysis, economic losses of more than 5,000 yuan, or serious consequences, punishable by up to five years in prison. Considering our losses just now, based on the data traffic fees and potential commercial value, sending him to work as a sewing machine would be more than enough."

"Hey Lao Liu, you're going to take the bar exam too?" Zhang Jian said with a smile, stubbing out his cigarette.

"Get lost, let's get down to business. Third brother, gather the evidence and give it to second brother to draft the materials. Seal and print out the diary. Tomorrow morning, send this senior off on his final journey."

Just then, Bai Yuhang's pager on the table vibrated.

Bai Yuhang went to the front desk and made a phone call, his tone instantly switching back to that of a relaxed and talkative person.

"Mr. Zhang, it's you! Why are you still up so late?"