Security Bulletins

A prompt response to software defects and security vulnerabilities is a top priority for Antora. Even though threats are a fact of life, we take quality assurance seriously with nearly 100% test coverage. This page documents the items that slipped through and how to address them.

Security Bulletin ANTORA-350




November 26, 2018


For a brief window of time, version 0.1.1 of flatmap-stream entered Antora’s runtime dependency chain (via gulp-vinyl-zip → event-stream → flatmap-stream). This package is known to contain malicious code that runs an encrypted payload targeting a very specific application. The dependency was brought in by event-stream via gulp-vinyl-zip during that time period.

The malicious package was promptly removed from the npm registry and is no longer in Antora’s runtime dependency chain. Furthermore, gulp-vinyl-zip has locked the version of event-stream to 3.3.4, which does not depend on flapmap-stream. However, the flatmap-stream 0.1.1 package could still be installed on the user’s machine. Additionally, if the user’s project uses a package lock file (i.e., package-lock.json or yarn.lock), that could cause the npm client to request the removed package (which would fail).

This bulletin may not affect Antora users since Antora doesn’t use a crypto-currency package, which is required for the malicious code to work. But it could put other applications at risk given that installing Antora caused this package to be installed.

Anyone installing Antora today with a clean npm package cache won’t be affected. Antora will grab a version of gulp-vinyl-zip that does not depend transitively on flatmap-stream. The published Docker images for Antora are also fine. Although version 1.1.1 of the Docker image uses event-stream 3.3.6, it grabbed flatmap-stream 0.1.0, which does not contain the malicious code.

This bulletin only affects users who installed Antora during the brief period when flatmap-stream 0.1.1 was in the npm repository. See the Solutions section for analysis and mitigation steps.

We’ve requested the gulp-vinyl-zip project to find a replacement for the event-stream library, which is now deprecated (as a result of this incident).

Affected Versions

Antora Package Versions Platforms







Default UI build




You can check if you’ve been affected by looking for version 0.1.1 of flatmap-stream in your list of installed. Here are the commands you can use to check:

$ npm ls flatmap-stream | grep flatmap-stream@0.1.1
  npm ls -g flatmap-stream | grep flatmap-stream@0.1.1
  yarn list --pattern=flatmap-stream | grep flatmap-stream@0.1.1
  (cd $(yarn global dir); yarn list --pattern=flatmap-stream@0.1.1)

If any of these commands produce output, then you’re affected. You should promptly uninstall and reinstall Antora (which you only have to do once). Otherwise, you are fine.

Global installation:

npm (global install)
$ npm uninstall -g @antora/site-generator-default
  npm install -g @antora/site-generator-default@~$(antora version)
npm (local install)
$ rm -f package-lock.json node_modules
  npm i
yarn (global install)
$ yarn global remove @antora/site-generator-default
  yarn global add @antora/site-generator-default@~$(antora version)
yarn (local install or UI project)
$ rm -f yarn.lock node_modules

Once you execute these commands, the flatmap-stream package should no longer be installed as part of Antora’s dependency chain. However, if you have other applications that depend on a package that uses flatmap-stream, the package may remain. In that case, it’s best to clear all the installed node packages from your machine. Since the malicious package is no longer in the npm registry, it will never be installed again.