dxbjavid opened a new pull request, #403: URL: https://github.com/apache/commons-net/pull/403
**Untrusted class name from the SYST reply is instantiated during listing auto-detection** When `FTPClient.listFiles()` runs without an explicit parser key or config it auto-detects the parser from the server's `SYST` reply, and `DefaultFTPFileEntryParserFactory` treats a reply that looks like a qualified class name as a class to load. It calls `Class.forName` and then `getConstructor().newInstance()`, only catching the `ClassCastException` afterwards, so the constructor and static initialiser of any class on the client's classpath run before the type is ever checked. A malicious or intercepted server can reply to `SYST` with the name of an arbitrary classpath class and have it built for its side effects (CWE-470). The impact is limited to classes already present, but it is still an unintended instantiation driven by remote input. The type check is moved ahead of construction with `isAssignableFrom`, so unrelated classes are rejected before their constructor runs. The documented behaviour of passing your own parser class name is unchanged, since real parser classes still load and construct as before. - [x] Read the [contribution guidelines](CONTRIBUTING.md) for this project. - [ ] Read the [ASF Generative Tooling Guidance](https://www.apache.org/legal/generative-tooling.html) if you use Artificial Intelligence (AI). - [ ] I used AI to create any part of, or all of, this pull request. Which AI tool was used to create this pull request, and to what extent did it contribute? - [ ] Run a successful build using the default [Maven](https://maven.apache.org/) goal with `mvn`; that's `mvn` on the command line by itself. - [x] Write unit tests that match behavioral changes, where the tests fail if the changes to the runtime are not applied. This may not always be possible, but it is a best practice. - [x] Write a pull request description that is detailed enough to understand what the pull request does, how, and why. - [x] Each commit in the pull request should have a meaningful subject line and body. Note that a maintainer may squash commits during the merge process. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
