CVE-2009-0884 Scanner

FileZilla Server is a popular open-source FTP server used for transferring files across networks. It is widely used by organizations and individuals to set up a secure file server for local and remote file transfers. The server supports various protocols, including FTP and FTPS, and is known for its robust performance and ease of use. FileZilla Server is typically used in IT environments for delivering and retrieving files and is appreciated for its cross-platform compatibility and user-friendly interface. Its lightweight design makes it suitable for both small-scale personal servers and large enterprise-level deployments. Organizations utilize FileZilla Server to manage file transfers across different departments and for external communications with clients and partners.

A buffer overflow occurs when more data is input into a buffer than it can handle, causing the excess data to overwrite adjacent memory. This type of vulnerability can lead to various issues, including crashes and security breaches. In the context of FileZilla Server, the buffer overflow is related to the SSL/TLS packet handling. This allows remote attackers to potentially crash the server by sending specially crafted packets. Buffer overflows are particularly dangerous as they can also pave the way for executing arbitrary code. Proper handling and validation of input data are crucial to preventing such vulnerabilities. Such overflow flaws are common in software that interacts with network protocols and require meticulous coding practices to avoid.

The vulnerability lies in how FileZilla Server versions prior to 0.9.31 handle SSL/TLS packets. Attackers can exploit this flaw by crafting specific packets that cause the application to fail in managing buffer memory safely. The endpoint involved in this vulnerability is associated with the server's network interface that processes incoming SSL/TLS packets. The parameter that becomes vulnerable is linked to the data size within these packets. FileZilla fails to check the packet size against the buffer capacity, resulting in an overflow. If not patched, repeated exploitation attempts could cause resource exhaustion and service interruptions. This technical flaw necessitates updates in packet parsing logic to ensure memory safety.

Exploitation of this vulnerability can lead to a denial of service, rendering the FileZilla Server inoperable. When an attacker sends a carefully designed packet to exploit the buffer overflow, it causes the server to crash. This disrupts file transfer operations and can halt business activities relying on the server's availability. The financial impact of such an interruption could be significant, especially in environments that depend heavily on continuous data exchange. Additionally, recurring server downtime might trigger customer dissatisfaction and damage an organization's reputation. While the primary impact is denial of service, the potential for executing unauthorized code could escalate the situation, although this specific flaw targets service availability.

REFERENCES

• http://sourceforge.net/project/shownotes.php?release_id=665428
• http://www.vupen.com/english/advisories/2009/0603
• https://exchange.xforce.ibmcloud.com/vulnerabilities/49107