Apache Camel FTP: crafted directory listing reads and deletes files outside polled folder

Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') vulnerability in Apache Camel FTP component.

This issue affects Apache Camel: from 4.0.0 before 4.18.5, from 4.19.0 before 4.22.1.

The Camel remote-file consumers poll a directory on a remote server and build the absolute remote path of each file by concatenating the configured directory with the file name reported in the server's directory listing. That concatenation (FtpUtils.absoluteFilePath and GenericFileConsumer) applied no lexical normalization and no check that the result stayed inside the directory being polled, and the resulting path became the operand for every subsequent remote operation on the file: retrieval (FtpOperations.retrieveFile / SftpOperations, reached from GenericFileConsumer where the retrieve name is taken verbatim from GenericFile.getAbsoluteFilePath), deletion when delete=true (GenericFileDeleteProcessStrategy), and renaming when move, preMove, moveFailed or readLock=rename is configured (GenericFileProcessStrategySupport and GenericFileRenameExclusiveReadLockStrategy). Neither isValidFile nor isMatched performed any containment check. A listing entry that is not a single path segment therefore resolved to a path outside the configured polling directory, causing Camel to read, delete or rename files outside it using the endpoint's own credentials. A listing name is not route-controlled data. It is supplied by the remote server, and the FTP control channel carries no integrity protection at all, so an on-path attacker can rewrite a LIST response without holding any credentials; a compromised, malicious or multi-tenant server, or a server backed by a virtual filesystem, can emit such a name directly. Retrieval is reachable in a default consumer configuration, since the remote consumers download every listed file; deletion and renaming additionally require one of the disposition options above, all of which are common. Escape from the directory Camel was configured to poll is unconditional, while escape from the server's own account boundary additionally depends on whether that server confines the account. The jailStartingDirectory option, which is documented as restricting Camel to the starting directory and is enabled by default, governed producer writes and, since the localWorkDirectory containment work, consumer downloads to the local work directory - but it did not constrain this remote operand, so its name and description claimed a boundary that was not enforced here. The same entry point had already been recognised on the local side: the localWorkDirectory download path was constrained so that a remote file name containing parent-directory segments could not resolve outside the local work directory. The remote operand was the remaining half of that surface. This artifact provides the ftp, ftps and sftp schemes, all of which are affected. The reporter demonstrated the issue end to end against an ftp endpoint, driving a Camel route with a malicious server whose LIST response named a file outside the polled directory.

Upgrade to Apache Camel 4.23.0, which fixes the issue. Users on the 4.22.x releases stream should upgrade to 4.22.1. Users on the 4.18.x LTS releases stream should upgrade to 4.18.5. The 4.14.x stream reached end of life and does not receive this fix; users on it should move to a supported releases stream.