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Lao Wang is also a technician, and has rich experience, and he is more accurate when he is middle-aged. Pen | fun | pavilion www. ｂｉｑｕｇｅ。 infoAmong so many people present, Lao Wang only valued Lin Hong more, and only his level was higher than his own.

Lao Wang's personality is relatively introverted, and he rarely takes the initiative to talk to others, but he has an impulse in his heart to get to know Lin Hong. This young man is too sudden, and the most important thing is that he is still very young.

Looking at him, Lao Wang even had a faint envy and jealousy, youth is the biggest capital!

In the face of Lao Wang's inquiry, Lin Hong smiled, did not hide it, and replied: "Little brother, I opened a company with my friend, specializing in the development of embedded systems. ”

Lin Hong only noticed at this time that Lao Wang's right leg was a little inconvenient, or deformed, and he limped when he walked.

Seeing Lin Hong set his eyes on his right leg, Lao Wang said indifferently: "When I was a child, I was disabled by polio. ”

Lin Hong nodded slightly.

Polio is also polio, in the past, the medical conditions were poor, and children were rarely vaccinated, and the proportion of people with this disease was relatively high, and it would leave very serious sequelae, Lao Wang should be one of these people.

"Lao Wang, which company are you currently working in?" Lin Hong also asked with some curiosity.

Lao Wang shook his head: "Like you, I also started a small company by myself, specializing in antivirus software. By the way, this is my business card, and maybe our two companies will have the opportunity to cooperate in the future. ”

As he spoke, Lao Wang took out a white business card from his pocket.

Business cards are simple. There is no pattern, only the name, contact number and company name are printed. I saw that it said "Beijin Dongming High Technology Co., Ltd." ”

"It's funny, the title is high-tech, but in fact, the technology content is not high. It's just that I am a disabled person, and it is not easy to open a company, and the relevant departments take special care of it. Lao Wang showed a look of self-deprecation on his face.

Lin Hong naturally would not say anything about this. He put away Lao Wang's business card, put it in his pocket, and said, "Wait until the drill is over." I'll visit your company. There should be opportunities for cooperation in the future. ”

"Very welcome!"

Then, they began to scan the adversary's servers and devices.

When Lao Wang saw the news coming back, he immediately said, "Yes." They also use the UNIX system! ”

Lin Hong heard his words, and also used the network command detection to probe from all angles, Lao Wang was right, one of the systems used on the device is openbsd, this branch version, shorter than freebsd, was officially launched last year.

However, since this system is BSD-based, progress is also very fast. Version 1.2 came out in July last year, and version 2.0 came out just three months later.

This system can even be said to be more focused on performance in terms of safety.

'It seems that the Blues have a good game, too.' Lin Hong nodded, "But that's more interesting!" ”

"You're right!" Lao Wang was deeply convinced of Lin Hong's words. It's the chess opponent that makes them happy.

Then, they gathered everyone together, rearranged the tasks, and each person was responsible for a part of the content, and then began to detect each other's targets.

The next thing is boring, just keep looking for each other's information. It is then analyzed to find vulnerabilities.

Lin Hong found that the other party also opened port 80 and opened the Apache service, and it seems that the other party uses the method of communication is through web services.

From this point of view alone, the right side is a little behind the Red Army.

If Apache is well configured, although there are few vulnerabilities and it is relatively safe, there are still vulnerabilities after all. At least Lin Hong has several ways to successfully break through. Some of the vulnerabilities he has are Apache own, while others are internal flaws in the programming language.

However, Lin Hong did not rush to make a move, but slowly probed to see how many ways there were to successfully break through, and at the same time estimated the level of the other party.

There are some loopholes, not that the other party wants to make up for them, the existence of these vulnerabilities, not that the other party's level is not good, but the existence of the platform itself, such as the vulnerabilities in the router, if you haven't studied it specifically, you don't know that you can make a fuss about it.

While Lin Hong and Lao Wang were probing each other, the others were not idle.

Some of them, like Xiao Jiang, continue to add defenses to their systems and configure security policies, while others like Liu Hui are busy showing themselves, taking out "big killers" from their private "treasure troves" and starting to frantically carry out data storm attacks on each other.

A data storm attack, also known as a flood attack, exploits a flaw in the three-way handshake protocol to forge a large number of connection requests.

Since these requests for connection are forged and the source address is fake, after the application is issued, the other party's server will always broadcast an external response, asking the applicant to confirm or reject again, if no one responds again, the server will continue like this, forming a large number of semi-connected states, so that the semi-connected queue of the port will soon be full, and the service for other valid requests will not be available.

Therefore, this flood attack is also called a denial-of-service attack.

With Liu Hui's current level of flood attack, the effect on the bandwidth of their server is not great. Only distributed denial-of-service attacks, or DDoS, are most effective. However, in order to use DDoS attacks, a large number of machines must be involved.

Of course, it is also good to be able to consume some of the other party's network resources, and it does not mean that Liu Hui's attack at the moment is meaningless, at least it also disturbs the other party's line of sight.

Lin Hong doesn't like data storm attacks very much, because this kind of attack has no technical content and lacks skills, just like when fighting, he fights with the opponent completely with his own brute strength, but has little wisdom.

He didn't want to use a buggy exploit that was too frightening, so he decided to start from a normal point of view and make an overflow attack program against the other party's system. Although he hasn't done a lot of research on OpenBSD, one thing is certain, there must be one kind of overflow attack vulnerability in the Unix series of systems.

It's not the system that's decided, it's the programming language.

The UNIX series of systems are all written in C, and one of the important characteristics of C language is that it is easy to overflow vulnerabilities. This is not a defect in the language, but a lack of rigor on the part of the programmer.

There are too many programs in the system, and there are thousands of lines of code, and there will always be people who are careless and do not strictly check the various memory boundaries, which leaves an opportunity for attackers to take advantage of.

Lin Hong queried through the server of the other party with specific instructions, and got the version number of the other party's apache, and found that it was not the latest version, he remembered that when he was setting up the website, he had found an overflow vulnerability in apache, and he did not study it in depth at that time.

He downloaded this version from the FTP on the official website, and then debugged it directly on his own machine. Directly from memory, the overflow vulnerability was tested, and it was finally found that the vulnerability has not been fixed so far.

It is very likely that the spillover vulnerability was too small and stealthy to attract the attention of the development team and did not cause any harm, so it was never discovered.

Since there is such a breakthrough, Lin Hong did not think of other methods, but continued to analyze this overflow vulnerability to see if it could be allowed to execute its own specific overflow program.