Buffer Overflow

Definition

• Occurs when a program writes more data to a buffer than it can hold or writes data beyond the allocated buffer size.
• Can lead to data corruption, program crashes, or execution of malicious code.

Vulnerable Applications

• SLmail 5.5
• Golden FTP Server 4.70
• Ultra MiniHTTPd 1.2
• CloudMe 1.11.2
• Easy File Sharing Web Server 7.2

Practice Targets

• These applications are susceptible to stack-based buffer overflow attacks.
• Practicing on them helps understand and mitigate such vulnerabilities.

Consequences

• Data Corruption: Overwriting adjacent memory can corrupt data structures.
• Program Crashes: Writing beyond buffer boundaries can cause the program to crash.
• Malicious Code Execution: Attackers can exploit buffer overflow vulnerabilities to inject and execute arbitrary code.

Mitigation Techniques

• Input Validation: Ensure input data doesn't exceed buffer limits.
• Bounds Checking: Implement checks to prevent buffer overflow.
• Use Secure Libraries: Utilize functions that handle buffers safely (e.g., strcpy_s instead of strcpy).
• Code Reviews: Regularly review code for potential vulnerabilities.
• Address Space Layout Randomization (ASLR): Randomize memory locations to make it harder for attackers to predict addresses for exploitation.