GHSA-rvp4-r3g6-8hxq Insufficiently Protected Credentials via Insecure Temporary File in org.apache.nifi:nifi-single-user-utils

• Maven org.apache.nifi:nifi-single-user-utils: < 1.16 → fixed in 1.16

Impact `org.apache.nifi.authentication.single.user.writer.StandardLoginCredentialsWriter` contains a local information disclosure vulnerability due to writing credentials (username and password) to a file that is readable by all other users on unix-like systems. On unix-like systems, the system's temporary directory is shared between all users on that system. As such, files written to that directory without setting the correct file permissions can allow other users on that system to view the contents of the files written to those temporary files. Source An insecure temporary file is created here: • https://github.com/apache/nifi/blob/6a1c7c72d5b91b9ce5d5cb5b86e3155d21e2c19b/nifi-commons/nifi-single-user-utils/src/main/java/org/apache/nifi/authentication/single/user/writer/StandardLoginCredentialsWriter.java#L75 The username and password credentials are written to this file here: • https://github.com/apache/nifi/blob/6a1c7c72d5b91b9ce5d5cb5b86e3155d21e2c19b/nifi-commons/nifi-single-user-utils/src/main/java/org/apache/nifi/authentication/single/user/writer/StandardLoginCredentialsWriter.java#L85-L95 Patches The vulnerability has been patched in version `1.16`. Prerequisites This vulnerability impacts Unix-like systems, and very old versions of Mac OSX and Windows as they all share the system temporary directory between all users. Workarounds Setting the `java.io.tmpdir` system environment variable to a directory that is exclusively owned by the executing user will fix this vulnerability for all operating systems. References • https://issues.apache.org/jira/browse/NIFI-9785 • https://github.com/apache/nifi/commit/859d5fe • https://github.com/apache/nifi/pull/5856 • https://nifi.apache.org/security.html#CVE-2022-26850 • https://twitter.com/JLLeitschuh/status/1511736635645435904?s=20&t=I3w3zF6Y2DUvWYsEFqERjg