👉 Overview
👀 What ?
FTP Bounce is a known vulnerability in the File Transfer Protocol (FTP) that allows an attacker to use the PORT command to request access to ports indirectly through the use of the victim's machine as a middle man for the request. This vulnerability was first discovered in 1995 and is still present in many FTP servers today. The 2ºFTP file download refers to the second step in the FTP Bounce attack where the attacker downloads files from a remote server to their local machine.
🧐 Why ?
Understanding the FTP Bounce attack and the process of 2ºFTP file download is important because this vulnerability is still present in many FTP servers today. It poses a serious security risk as it allows an attacker to bypass network security measures and gain unauthorized access to network systems and sensitive data. Furthermore, it can be used to perform anonymous or untraceable attacks.
⛏️ How ?
To perform a FTP Bounce attack, the attacker first needs to identify a vulnerable FTP server. Then, the attacker would use the PORT command to request the server to send data to a specific port on a third-party machine (the victim). Once the data is sent to the victim's machine, the attacker can then use the RETR command to download the data. It is important to note that this is a high-level overview and the actual steps may vary depending on the specific FTP server and network settings.
⏳ When ?
FTP Bounce attacks have been known since 1995 when the vulnerability was first discovered. Despite various security measures and patches, this vulnerability is still present in many FTP servers today, making it a prevalent issue in the field of cybersecurity.
⚙️ Technical Explanations
The FTP Bounce attack exploits the way the File Transfer Protocol (FTP) handles the PORT command. In a typical FTP session, the client uses the PORT command to tell the server where to send data. However, the FTP protocol does not require that the data be sent back to the client. This means that an attacker can use the PORT command to tell the server to send data to a different machine, effectively bouncing the data off the victim's machine. The 2ºFTP file download refers to the second step in the attack where the attacker downloads the files from the remote server to their local machine. This is achieved through the RETR command, which retrieves a copy of the file from the server. The server then sends the file to the specified port on the victim's machine, which is then downloaded by the attacker.