Chapter 475 Play with a flower

Blue Army Information Confrontation Center.

Both Ding Huahui and Li Yushan were very surprised by the IP data report they saw.

They didn't expect that such a simple datagram could make OPENBSD crash directly, so they had to restart and aim at it one by one.

Understanding its basic principles, Ding Huahui quickly came up with a coping strategy.

He directly set a filter rule to filter out data packets from the server's own IP, and it is very easy to fix this bug directly.

Then, he asked the server to go back online. After all, the server cannot disconnect the network for too long, otherwise points will be deducted.

"It seems that this attack method was newly discovered by the other party." Li Yushan said after looking at this data packet for a long time.

Ding Huahui nodded: "Yes, I haven't heard of this loophole before."

In the TCP/IP protocol, the principle of three handshakes looks very humane and in line with the principle of people's communication. But in fact, this principle is the most exploited vulnerability in attacks on TCP/IP protocols.

The most common is the denial of service attack on DOS to randomly construct an illegal connection and consume the resources of the server. The upgraded version of DOS is DDOS, that is, a distributed denial-of-service attack that uses multiple computers to attack the target server.

In addition, there is another kind of "death attack", that is, PING_OF_DEATH. According to the TCP/IP specification, the maximum length of a package is 65536 bytes. Although the length of a package cannot exceed 65536 bytes, the superposition of multiple fragments divided into a package can be achieved. WHEN A HOST RECEIVES A PACKAGE GREATER THAN 65536 BYTES IN LENGTH, IT IS ATTACKED BY PING_OF-DEATH, WHICH CAN ALSO CAUSE THE HOST TO CAIL.

Lin Hong's attack is also to build illegal data packets, so that the host can be successfully crashed.

Everyone is thinking about this place, and all kinds of strange loopholes have been dug out.

When programmers compiling programs, they did not fully take into account these strange situations, so there were all kinds of strange loopholes.

Although the loophole found by Lin Hong is very simple in principle, it is a loophole that has never been made public before. In this respect, it belongs to his first. Moreover, judging from this action, the consequences of this vulnerability are very serious, which can directly cause some UNIX-like systems to crash and restart.

"It seems that the other party is really a master!" Li Yushan said, "This kind of attack has appeared. Let's have twelve points of spirit, and the other party will definitely have follow-up attack methods!"

"What is the purpose of his sending such a packet? Is it just to let our server restart? Ding Huahui raised the doubts in his heart.

As soon as his voice fell, he suddenly found that the OPENBSD in front of him seemed to be not working well again.

The system becomes extremely slow, typing in a character, which is simply delayed by one to two seconds to respond.

Ding Huahui changed his face and said, "Here we go again!"

"Didn't you just filter the local IP?" Li Yushan is a little strange.

Ding Huahui was slightly stunned: "Yes, I filtered it!"

After saying this, both of them know what it means - the current attack must be another way!

Although the system has become slow, it can still be operated.

Ding Huahui immediately typed in a line of commands, which once again restricted the external network connection of this machine.

At this time, the system runs smoothly.

Ding Huahui immediately checked the system log and checked the network connection record just now.

After seeing the record, he couldn't help wondering: "It's strange that the IPs attacked are all from the machines of our subordinate units."

Hearing his words, Li Yushan couldn't help checking the record carefully.

Indeed, the dense connection records in the connection log are all Class C IP addresses. At a glance, you can see that it is the IP segment from their subordinate units.

"Have they broken through the client machines of their subordinate units?" Ding Huahui said doubtfully.

"Impossible, how can so many machines be broken in such a short time? There was no sign before. Li Yushan first denied this statement.

He immediately asked someone to call the network administrator of his subordinate unit.

Soon, the results were reported, and they did not find any abnormality.

"Are these packets disguised by them?"

Based on this idea, Li Yushan asked the network manager of his subordinate unit to send a log, and then analyzed it himself.

Finally, it was found that they had received a large number of application connections from the server during the period just now.

Li Yushan smiled bitterly on his face: "So that's it!"

Ding Huahui immediately understood this log as soon as he saw it.

Their servers certainly did not send connection applications like those clients. Obviously, these packets were sent from the Red Army. However, when they send it, they disguise the source address as the IP address of the server, so that those clients directly reply the confirmation signal to the server when they reply.

That is to say, these clients are used as guns! And at the same time, it was used as an amplifier, amplifying their attack.

"It's a new way of attack!" Ding Huahui muttered.

He has never encountered this way before.

Although it is not necessarily created by the other party, it is brand new, at least for them.

Moreover, this attack takes advantage of the loophole of the three-way handshake principle.

Both Li Yushan and Ding Huahui know that the principle of three handshakes is not very reliable, and it is easy to be attacked by data storms. However, they never thought that only such a point would be played so much by the other party.

Even, they don't even know whether the other party has any other means that have not been used.

The two of them looked at each other with a helpless look in their eyes.

At the same time, Lin Hong is sitting in front of Liu Hui's machine, using Liu Hui's original software to send his modified data packets, while explaining the principle of the attack he is using now.

After hearing his words, everyone couldn't help but be stunned.

They never thought that an attack effect similar to DDOS could be obtained in this way alone. That is to say, Lin Hong did not invade the other party's machines at all, but successfully regarded them as a broiler-like attack tool.

"This idea is really amazing!" Liu Hui couldn't help praising, "Why didn't I think of it before!"

Speaking of which, the principle is not complicated, but no one has ever thought of it before.

Many things are like this. There may be only a slight difference between methods and methods, but the effect is very different. If no one else can say it, I will never think of it and have been immersed in the mindset.

At this moment, Lin Hong has completely won everyone's admiration and respect. ( To be continued