Use of web applications and electronic bulletin board systems has become increasingly popular and plays an important role in our day to day life. Today, users want to read, post, and respond to just about everything they can on the Internet. The problem is that many web applications and bulletin board platforms contain sensitive data that hackers try to exploit and steal useful information. The applied research examines the security of the phpBB3 platform by performing five security attacks (packet sniffing, forum spamming, session hijacking, SQL injection, and XSS scripting). The results revealed successfully security breaches and vulnerabilities exists within the phpBB3 platform. Based upon these result, this research provided recommends and countermeasures to reduce the vulnerabilities and improve phpBB3 security.