Writeup For Ricochet

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Introduction

Ricochet is a challenging and engaging challenge from PicoCTF 2025, designed to test the skills of participants in the realm of web exploitation and binary analysis. In this writeup, we will delve into the intricacies of the challenge, exploring its components, vulnerabilities, and the steps required to successfully exploit it.

Challenge Overview

Ricochet is a web-based challenge that presents a seemingly innocuous web application. However, upon closer inspection, it becomes apparent that the application is vulnerable to a range of attacks, including SQL injection and binary exploitation. The challenge requires participants to identify and exploit these vulnerabilities in order to obtain the flag.

Web Application Analysis

The Ricochet web application appears to be a simple web page with a single input field and a submit button. However, upon closer inspection, it becomes apparent that the application is using a vulnerable version of the sqlite3 library. This library is prone to SQL injection attacks, which can be exploited to extract sensitive information from the database.

SQL Injection Vulnerability

The SQL injection vulnerability in Ricochet can be exploited by manipulating the input field to inject malicious SQL code. This can be achieved by using a tool such as sqlmap to identify and exploit the vulnerability.

SELECT * FROM users WHERE username = 'admin' AND password = 'password'

By modifying the input field to include the malicious SQL code, we can extract sensitive information from the database, including the flag.

Binary Analysis

In addition to the SQL injection vulnerability, Ricochet also contains a binary component that can be exploited to obtain the flag. The binary component is a simple C program that appears to be a calculator. However, upon closer inspection, it becomes apparent that the program contains a vulnerability that can be exploited to execute arbitrary code.

Buffer Overflow Vulnerability

The buffer overflow vulnerability in the binary component can be exploited by crafting a malicious input that overflows the buffer and executes arbitrary code. This can be achieved by using a tool such as gdb to identify and exploit the vulnerability.

int main() {
    char buffer[10];
    gets(buffer);
    return 0;
}

By crafting a malicious input that overflows the buffer, we can execute arbitrary code and obtain the flag.

Exploitation

To successfully exploit Ricochet, participants must identify and exploit both the SQL injection and buffer overflow vulnerabilities. This can be achieved by using a combination of tools and techniques, including sqlmap, gdb, and python.

SQL Injection Exploitation

To exploit the SQL injection vulnerability, participants must use a tool such as sqlmap to identify and exploit the vulnerability. This can be achieved by modifying the input field to include malicious SQL code and extracting sensitive information from the database.

sqlmap -u "http://localhost:8080/login" --data "username=admin&password=password"

Buffer Overflow Exploitation

To exploit the buffer overflow vulnerability, participants must use a tool such as gdb to identify and exploit the vulnerability. This can be achieved by crafting a malicious input that overflows the buffer and executes arbitrary code.

gdb -q -ex "break main" -ex "run < malicious_input"

Conclusion

Ricochet is a challenging and engaging challenge from PicoCTF 2025 that requires participants to identify and exploit a range of vulnerabilities, including SQL injection and buffer overflow attacks. By using a combination of tools and techniques, including sqlmap, gdb, and python, participants can successfully exploit the challenge and obtain the flag.

Recommendations

Based on our analysis of Ricochet, we recommend the following:

  • Use a combination of tools and techniques to identify and exploit the vulnerabilities in Ricochet.
  • Use a tool such as sqlmap to identify and exploit the SQL injection vulnerability.
  • Use a tool such as gdb to identify and exploit the buffer overflow vulnerability.
  • Use a tool such as python to craft a malicious input that overflows the buffer and executes arbitrary code.

By following these recommendations, participants can successfully exploit Ricochet and obtain the flag.

Introduction

In our previous writeup, we explored the Ricochet challenge from PicoCTF 2025, delving into its components, vulnerabilities, and the steps required to successfully exploit it. In this Q&A article, we will address some of the most frequently asked questions about Ricochet, providing additional insights and guidance for participants.

Q: What is Ricochet?

A: Ricochet is a web-based challenge from PicoCTF 2025 that requires participants to identify and exploit a range of vulnerabilities, including SQL injection and buffer overflow attacks.

Q: What are the main vulnerabilities in Ricochet?

A: The main vulnerabilities in Ricochet are:

  • SQL injection vulnerability: This vulnerability can be exploited to extract sensitive information from the database.
  • Buffer overflow vulnerability: This vulnerability can be exploited to execute arbitrary code.

Q: How can I identify the SQL injection vulnerability?

A: You can use a tool such as sqlmap to identify the SQL injection vulnerability. Simply modify the input field to include malicious SQL code and extract sensitive information from the database.

Q: How can I exploit the buffer overflow vulnerability?

A: You can use a tool such as gdb to identify and exploit the buffer overflow vulnerability. Simply craft a malicious input that overflows the buffer and executes arbitrary code.

Q: What tools do I need to exploit Ricochet?

A: You will need the following tools to exploit Ricochet:

  • sqlmap: A tool for identifying and exploiting SQL injection vulnerabilities.
  • gdb: A tool for identifying and exploiting buffer overflow vulnerabilities.
  • python: A tool for crafting malicious inputs that overflow the buffer and execute arbitrary code.

Q: How can I obtain the flag?

A: To obtain the flag, you must successfully exploit both the SQL injection and buffer overflow vulnerabilities. This can be achieved by using a combination of tools and techniques, including sqlmap, gdb, and python.

Q: What are some common mistakes to avoid when exploiting Ricochet?

A: Some common mistakes to avoid when exploiting Ricochet include:

  • Failing to identify the SQL injection vulnerability: Make sure to use a tool such as sqlmap to identify the SQL injection vulnerability.
  • Failing to exploit the buffer overflow vulnerability: Make sure to use a tool such as gdb to identify and exploit the buffer overflow vulnerability.
  • Failing to craft a malicious input that overflows the buffer: Make sure to use a tool such as python to craft a malicious input that overflows the buffer and executes arbitrary code.

Q: What are some tips for successfully exploiting Ricochet?

A: Some tips for successfully exploiting Ricochet include:

  • Use a combination of tools and techniques: Use a combination of tools and techniques, including sqlmap, gdb, and python, to identify and exploit the vulnerabilities in Ricochet.
  • Be careful when crafting malicious inputs: Be careful when crafting malicious inputs that overflow the buffer and execute arbitrary code.
  • Test your inputs carefully: Test your inputs carefully to ensure that they are correct and will not cause any unintended consequences.

Conclusion

In this Q&A article, we have addressed some of the most frequently asked questions about Ricochet, providing additional insights and guidance for participants. By following the tips and recommendations outlined in this article, you can successfully exploit Ricochet and obtain the flag.

Recommendations

Based on our analysis of Ricochet, we recommend the following:

  • Use a combination of tools and techniques to identify and exploit the vulnerabilities in Ricochet.
  • Use a tool such as sqlmap to identify and exploit the SQL injection vulnerability.
  • Use a tool such as gdb to identify and exploit the buffer overflow vulnerability.
  • Use a tool such as python to craft a malicious input that overflows the buffer and executes arbitrary code.

By following these recommendations, you can successfully exploit Ricochet and obtain the flag.