How Do Buffer Overflow Attacks Work? Going Behind-the-Scenes as a Hacker 2023

 How Do Buffer Overflow Attacks Work? Going Behind-the-Scenes as a Hacker

Here's an in-depth explanation of how buffer overflow attacks work:

Background:
A buffer overflow occurs when a program attempts to store more data in a buffer (temporary data storage) than it was intended to hold. This can overwrite adjacent memory locations and corrupt data.laptop bildschirm schwarz

Attack scenario:
A hacker wants to exploit a vulnerability in a program. They've found that the program has a fixed-size buffer of 100 bytes to store some input data.

1. The hacker first injects 101 bytes of data as input. This extra byte overflows the 100 byte buffer. At this point, the program still runs normally (no harm done yet).

2. Next, the hacker injects hundreds or thousands of bytes of input data. This overflow will overwrite valuable data stored after the buffer in memory, corrupting that data.

3. The hacker carefully crafts the overflowing input so that it contains executable code (machine instructions) they want to run.

4. When the overflow occurs, it overwrites the memory location that contains the program's "instruction pointer" - which points to the next code to execute.

5. The hacker's injected executable code is now being pointed to by the instruction pointer.

6. When program control flow shifts to the instruction pointer, the hacker's malicious instructions are executed instead of the program's! This allows the hacker to gain control.Chuwi gemibook

7. The hacker can now do things like:

   • Change data
   • Gain higher privileges
   • Install malware
   • Trigger denial-of-service states

So in summary, buffer overflow attacks work by:

1. Overflowing a fixed-size buffer
2. Overwriting memory with executable code
3. Redirecting program control flow to that code
4. Gaining control of the program and executing arbitrary instructions.

Hope this explanation helps! Let me know if you have any other questions.