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How buffer overflow can be exploited?
Attackers exploit buffer overflow issues by overwriting the memory of an application. For example, an attacker can overwrite a pointer (an object that points to another area in memory) and point it to an exploit payload, to gain control over the program.
What is the best preventative technique against buffer overflow attacks?
Writing secure code
Writing secure code is the best way to prevent buffer overflow vulnerabilities. When programs are written in languages that are susceptible to buffer overflow vulnerabilities, developers must be aware of risky functions and avoid using them wherever possible.
What are the two ways to prevent buffer overflow attacks?
How to prevent buffer overflow attacks
- Choose programming language wisely.
- Avoid risky library files.
- Validate input.
- Filter malicious input.
- Test applications predeployment.
- Enable runtime protections.
- Use executable space protection.
How does buffer overflow affect the flow of a program?
Buffer overflow is defined as the condition in which a program attempts to write data beyond the boundaries of pre-allocated fixed length buffers. This vulnerability can be used by a malicious user to alter the flow control of the program, leading to the execution of malicious code.
How to disable stack protection for buffer overflow?
In the presence of this protection, buffer overflow attacks will not work. We can disable this protection during compilation using the -fno-stack-protectoroption. For example, to compile a program example.cwith StackGuard disabled, we can do the following:
Why does strcpy ( ) cause a buffer overflow?
Because strcpy()does not check boundaries, a buffer overflow will occur. Since this program is a root-owned Set-UID program, if a normal user can exploit this buffer overflow vulnerability, the user can get a root shell. Note that the program gets its input from a file called badfile.
How to prevent buffer overflow in GCC compilation?
StackGuard Protection: GCC implements a security mechanism called StackGuard to prevent buffer overflows. In the presence of this protection, buffer overflow attacks will not work. We can disable this protection during compilation using the -fno-stack-protectoroption.