CVE-2020-9274 Scanner

Pure-FTPd is a free, secure, production-quality and standard-conformant FTP server. It is widely used by various organizations and individuals to facilitate file transfers over the network. The server supports a wide range of features and security mechanisms, offering flexibility and robustness for different environments. As a lightweight and efficient FTP server, Pure-FTPd is used in Linux and Unix systems, enhancing data communication processes. Its popularity stems from its focus on security, including features for hiding system files and chroot settings for user directories. Many hosting providers and companies integrate Pure-FTPd within their infrastructure for reliable and safe data transfers.

The Denial of Service (DoS) vulnerability identified in Pure-FTPd versions 1.0.49 arises from improper handling of the init_aliases() function within diraliases.c. This vulnerability leads to the use of an uninitialized pointer. When exploited, this leads to a condition where the FTP server can be made to crash, potentially disrupting service availability. The issue represents a significant threat to the network availability of services relying on Pure-FTPd for FTP transactions. This vulnerability allows remote attackers to exploit the bug without the need for valid credentials. The security flaw in question can impact any service relying on Pure-FTPd, potentially compromising the organization's operational stability.

In terms of technical details, the vulnerability resides specifically in how Pure-FTPd processes directory aliases in the init_aliases() function. Improper initialization of pointers in diraliases.c can lead to Pure-FTPd attempting to access memory incorrectly, which satisfies the conditions of a denial of service attack. Attackers can craft specific requests targeting this weakness, causing the server to access an uninitialized memory location, resulting in application crashes. This aspect of the vulnerability underscores the critical nature of buffer and memory management in server application development. Companies relying on this particular version or earlier iterations of Pure-FTPd need to be vigilant in addressing this vulnerability.

Successful exploitation of this vulnerability can result in a denial of service for any FTP operations that the Pure-FTPd server handles. The impact is typically limited to the temporary unavailability of file transfer services provided by the server. However, the repercussion might be more significant in environments dependent on continuous FTP operations, potentially affecting business operations or critical functions. Additionally, repetitive attacks could lead to prolonged downtime, potentially causing reputational damage and financial loss. The need for uninterrupted communication and data flow makes addressing this vulnerability imperative for organizations using this software.

REFERENCES

• https://lists.debian.org/debian-lts-announce/2020/02/msg00029.html
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/22P44PECZWNDP7CMBL7NRBMNFS73C5Z2/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/B5NSUDWXZVWUCL6R2PTX3KBB42Z62CA5/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/U5DBVHJCXWRSJPNJQCJQCKZF6ZDPZCKA/
• https://security.gentoo.org/glsa/202003-54