Threat Intelligence Database

SSHFS is a network filesystem client for connecting to SSH servers. From version 1.4 until 3.7.6, SSHFS accepts a bracketed mount source such as [-oProxyCommand=CMD]:/path and find_base_path() removes the brackets, leaving a host value that begins with - and is passed directly to ssh as a command-line argument. When a caller also supplies a path-valued sftp_server, ssh treats the normalized host as an option and the server path as its destination, causing an injected ProxyCommand to execute locally before any connection or authentication succeeds. The attack requires a caller or wrapper that passes an attacker-controlled mount source to SSHFS with the required sftp_server configuration and results in arbitrary command execution as the user running SSHFS. This issue is fixed in version 3.7.6.

SSHFS is a network filesystem client for connecting to SSH servers. Prior to version 3.7.6, a rogue SFTP server can return absolute symlink targets or relative targets containing parent-directory components that SSHFS passes through FUSE for resolution by the client kernel against the local filesystem. The documented transform_symlinks mitigation does not contain relative targets because transform_symlink() returns early at sshfs.c:2181, while sshfs_readlink() at sshfs.c:2234 to sshfs.c:2236 otherwise copies the server-supplied link target to the kernel. A victim or victim-side tool that follows such a link through ordinary operations such as cp, rsync, backup tooling, or an editor can disclose readable local files back to the server or write server-controlled content to writable local files, potentially including startup or scheduled-task files. This issue is fixed in version 3.7.6.