CompTIA CASP+ Practice Test

What is exemplified by the following code snippet: <code>char *code = "AAAABBBBCCCCDDD"; void main() { char buf[8]; strcpy(buf, code); }</code>?

1. Denial of Service

2. Buffer overflow attack

3. SQL injection

4. Cross-Site Scripting

The correct answer is: Buffer overflow attack

The provided code snippet illustrates a buffer overflow attack, which occurs when data exceeds the storage capacity of a buffer. In the code, a character buffer `buf` is defined with a size of 8 bytes. However, the string assigned to `code` contains 16 characters ("AAAABBBBCCCCDDD"). When the `strcpy` function is called, it attempts to copy the entire string into the `buf` variable without checking the size of the incoming data. This action leads to overwriting adjacent memory locations beyond the allocated buffer size, resulting in potential unintended behavior or exploitation of the program. Attackers often use buffer overflow vulnerabilities to execute arbitrary code, crash the program, or gain elevated privileges. Understanding this context is critical for recognizing the risk associated with functions like `strcpy`, which do not perform bounds checking. Recognizing such vulnerabilities is essential for developing secure software and following best practices, such as using safer alternatives like `strncpy`, which allows specifying the maximum number of bytes to be copied.