Buffer overflow attack is one of the most common and dangerous forms of cyber attacks. It involves overrunning a vulnerable application’s buffer memory with more data than it can handle. As a result, it allows attackers to execute malicious code, take control of the system and steal sensitive information.
The concept of buffer overflow attacks has been prevalent for decades now. In fact, the first-ever buffer overflow attack was discovered back in the 1980s. Despite a plethora of security protocols and measures, cybercriminals still use this method to launch successful attacks owing to various vulnerabilities that still exist in modern-day systems.
But what exactly is a buffer overflow attack, and how does it work? In this article, we will take a closer look at this method of attack and its potential effects.
## The Technical Definition of Buffer Overflow Attack
At a technical level, a buffer overflow attack occurs when a hacker feeds more data into a buffer than the allocated memory can handle. It is a type of memory exploitation that usually targets programs that have memory allocation vulnerabilities.
A buffer is a temporary memory storage unit for holding user inputs in the program. Buffers have a fixed amount of allocated memory, and when that memory capacity is exceeded, it causes a buffer overflow situation. When this happens, the additional data overruns into adjacent memory locations outside the buffer and causes unpredictable behavior in the system.
## How Buffer Overflow Attacks Work
In a buffer overflow attack, the hacker first sends a data input that exceeds the allocated memory buffer into the vulnerable application. It could be in the form of a command-line argument, URL entry, or even a form submission.
When the program receives the excess data, it writes the data beyond the bounds of the allocated memory temporarily, typically into adjacent memory locations or the stack, depending on the architecture of the machine. Hackers often include shellcode in the additional data, leading to a situation where the system executes code that was not meant to be there in the first place.
The hackers can inject code into the program and take control of the system, even the execution of the outside code. Once the attacker has taken control of the system, they can collect sensitive data and perform unwanted actions, such as stealing personal information or installing malware on the targeted device.
## Real-life Examples of Buffer Overflow Attack
Buffer overflow attacks have been responsible for some of the most notorious cyber incidents in recent history. Here are some of the well-known examples:
### Morris Worm
In 1988, a graduate student named Robert Morris Jr. designed and launched a worm that eventually disrupted much of the internet. It exploited the buffer overflow vulnerability in the Sendmail email server, infecting systems from a single vulnerable computer to nearly a tenth of the internet’s hosts. It caused widespread panic and led to protests from lawmakers calling for increased cybersecurity measures.
### Heartbleed
In March 2014, a two-year-old vulnerability called Heartbleed was discovered. It was a catastrophic vulnerability in the OpenSSL cryptographic library, which is responsible for providing secure HTTPS communication between systems. The bug affected sites like Yahoo and Google, and it allowed hackers to steal usernames, passwords and personal information from users.
### WannaCry
In May 2017, WannaCry ransomware emerged, using exploits like buffer overflow attacks to infect Windows computers. The attackers exploited a buffer overflow bug called EternalBlue, which allowed them to spread the ransomware to over two hundred thousand computers worldwide. The attack led to significant financial losses, with many businesses forced to pay hefty ransoms to retrieve their data.
## Preventing Buffer Overflow Attacks
There are a variety of methods to prevent buffer overflow attacks. Here are some of the common techniques:
### Code review and testing
Proper code review and testing practices can identify vulnerabilities and API usage errors in software. Code review activities ensure that the buffer length is validated and verified to prevent memory overflows.
### Input Validation
This method involves ensuring that input data meets the expected format and limits before being processed by the program. It ensures that the program processes inputs within the buffer limits and allocates and validates memory correctly.
### Using security testing tools
Security testing tools like SAST, DAST, and fuzz testing tools are used to test software applications for vulnerabilities. They scan the software program for memory allocation errors, buffer overflow, and other flaws that enable cyber-criminals to exploit the system.
## Conclusion
Buffer overflow attacks are among the most popular and hazardous types of cyber attacks. They have caused significant damage and losses to businesses and individuals alike, leading to calls for improved cybersecurity measures. As demonstrated in this article, the attacks can occur in numerous forms, and hackers can use them as a gateway to carry out more significant security breaches. It is essential to use preventative measures to safeguard against these attacks and stay vigilant for emerging threats. Ultimately, investing in cybersecurity should be a top priority for anyone looking to remain safe in today’s digital age.
