Advisories for Golang/Github.com/Drakkan/Sftpgo/V2 package

A flaw in the SSH service allows an authenticated client to crash the server by sending a malformed protocol message while opening a channel.

File pattern filters (denied_patterns / allowed_patterns) were evaluated on the destination of a copy only. A user holding the copy permission could copy a file denied by the filters to a permitted name and then read it. A recursive directory copy reproduced the contents of a restricted directory under a path where the filters do not deny them, and the hide policy was affected in the same way: a file …

The inline query parameter on the browsable-share file download and on the authenticated user file download suppressed Content-Disposition: attachment, so an HTML file stored in a share or home directory could be served as text/html and execute in SFTPGo's web origin (stored XSS).

The public web-client endpoint for partial ZIP downloads of a browsable share did not correctly confine the client-supplied files entries to the shared directory. A requester able to reach a public share could read files located outside the shared directory, as long as the target's canonical path begins with the shared directory's name.

In SFTPGo versions prior to 2.7.1, a path normalization discrepancy between the protocol handlers and the internal Virtual Filesystem routing can lead to an authorization bypass. An authenticated attacker can craft specific file paths to bypass folder-level permissions or escape the boundaries of a configured Virtual Folder.

SFTPGo versions before v2.7.1 contain an input validation issue in the handling of dynamic group paths, for example, home directories or key prefixes. When a group is configured with a dynamic home directory or key prefix using placeholders like %username%, the value replacing the placeholder is not strictly sanitized against relative path components. Consequently, if a user is created with a specially crafted username the resulting path may resolve to …

SFTPGo supports execution of a defined set of commands via SSH. Besides a set of default commands some optional commands can be activated, one of them being rsync: it is disabled in the default configuration and it is limited to the local filesystem, it does not work with cloud/remote storage backends. Due to missing sanitization of the client provided rsync command, an authenticated remote user can use some options of …

The OpenID Connect implementation, in the affected SFTPGo versions, allows authenticated users to brute force session cookies and thereby gain access to other users' data, since the cookies are generated predictably using the xid library and are therefore unique but not cryptographically secure.

One powerful feature of SFTPGo is the ability to have the EventManager execute scripts or run applications in response to certain events. This feature is very common in all software similar to SFTPGo and is generally unrestricted. However, any SFTPGo administrator with permission to run a script has access to the underlying OS/container with the same permissions as the user running SFTPGo, so they can access the database and server …

In SFTPGo 2.6.2, the JWT implementation lacks certain security measures, such as using JWT ID (JTI) claims, nonces, and proper expiration and invalidation mechanisms.

SFTPGo WebAdmin and WebClient support password reset. This feature is disabled in the default configuration. In SFTPGo versions prior to v2.6.1, if the feature is enabled, even users with access restrictions (e.g. expired) can reset their password and log in.

SFTPGo is configurable SFTP server with optional HTTP/S, FTP/S and WebDAV support. SFTPGo WebAdmin and WebClient support login using TOTP (Time-based One Time Passwords) as a secondary authentication factor. Because TOTPs are often configured on mobile devices that can be lost, stolen or damaged, SFTPGo also supports recovery codes. These are a set of one time use codes that can be used instead of the TOTP. In SFTPGo versions from …