Automatic Plugin Security Updates

The WordPress.org security and plugin review teams have recently been working together to push automatic security updates for plugins to fix critical vulnerabilities. These updates are supported by WordPress 3.7+.

Andrew Nacin, a fellow lead developer of WordPress who helped write this post, wrote this after WordPress 3.7 was released:

“The automatic updater also supports themes and plugins on an opt-in basis. And by default, translations (for themes, plugins, and eventually core) are updated automatically. At some point in the future, the WordPress.org plugin security team will be able to suggest that installs automatically update malicious or dangerously insecure plugins. That’s a huge win for a safer web.”

Some have interpreted this as the end-user is required to opt-in, but it’s always been the case that it could be opt-in by either the site administrator, or by the WordPress.org security team if we deemed an issue severe enough to warrant it.

Back in April of 2014, the WordPress.org security team was contacted by Automattic with the details of a security issue affecting Jetpack, looking for help to get the update out to affected users as fast as possible (you can read more about that release over on the Jetpack Blog).

The team ultimately decided that leveraging our ability to issue a background update was the best option for the security of any WordPress site running the plugin. This decision was not made lightly, as it was the first time we would use the functionality.

A situation where we would have used automatic plugin updates was the security incident in July of 2011 where accounts of three plugin authors were breached and malicious updates were released. We were able to confirm that no other plugins were affected, as a precaution we reset the passwords of all WordPress.org users, but tens of thousands of sites were updated to a malicious version during a narrow window.

Unfortunately we weren’t so lucky back then, as we didn’t have automatic updates available to us. Thankfully, the malicious updates were detected quickly. But if a plugin author’s account is ever compromised again in the future, we’ll be able to remove the malicious update, and then push a security update for any site affected ASAP.

Since WordPress 3.7 was released, many sites have used the plugin automatic updates functionality, either by opting in directly through filters, or by using one of the many remote management services for WordPress that are available. We’ve had very few bug reports from those early users of the automatic plugin update functionality.

What is the process for the security team to push an update for a plugin?

The WordPress.org security team has only recently started to push more of these updates, only a handful of plugins have received the treatment, with vulnerability severity ranging from major to critical, affecting anywhere from 10,000 active installs to more than a million (Such as the WordPress SEO plugin this past week).

The process of approving a plugin for an automatic update, and rolling it out to WordPress users, is highly manual. The security team reviews all code changes in the release, verifies the issue and the fix, and confirms the plugin is safe to trigger an update. Rolling out an automatic update requires modification and deployment of the API code. This is the same standard and process for a core security release.

Because the process of pushing these updates is relatively recent, we haven’t previously formulated any guidelines as to when these pushes happen. We’re still iterating on them, but the current criteria we take into consideration for a security push is a simple list:

  1. Has the security team been made aware of the issue?
  2. How severe is the issue? What impact would it have on the security of a WordPress install, and the greater internet?
  3. Is the fix for the issue self-contained or does it add significant extra superfluous code?
  4. If multiple branches of the plugin are affected, has a release per branch been prepared?
  5. Can the update be safely installed automatically?

These requirements are defined in a way that anyone should be able to tick each box. (If a plugin author needs help, we’ll help them to make that happen.)

The first criterion — making the security team aware of the issue — is critical. Since it’s a tightly controlled process, the WordPress security team needs to be notified as early as possible. Letting us know is as simple as emailing us at plugins@wordpress.org with the details. If you’re not the plugin author, we’ll put you in touch with the plugin author and help coordinate the fix.

We’ll work with the plugin author (and the reporter, if different) to study the vulnerability and its exact exposure, verify the proposed fix, and determine what versions will be released and when.

As with WordPress core security releases, we prefer to see plugin releases which fix only the security issue, with minimal code changes and with no unrelated changes. It allows us to review the changes quickly and to be far more confident in them.

If a plugin has a security vulnerability in versions 2.0–2.1.1, and 2.1 introduced several new features but 2.1.1 only fixed a few minor bugs, we’d enable an automatic update for 2.1.x to 2.1.2 but not for 2.0.x to 2.1.2. If a significant amount of installs still used 2.0, we’d ask for a 2.0.x release to be made, which 2.0.x users would be updated to, securing their installations, but without significantly changing the plugin they run. (For Jetpack’s release, release packages were generated from 11 different branches.)

We want code changes to be minimal. The plugin shouldn’t require additional assistance during the update process in the form of user interaction or an upgrade routine — we want the process to “just work” every time.

Millions have received automatic updates for security releases of WordPress core. We want automatic plugin updates to be as safe, and as trusted.

We hope this clarifies why and when we’ll push automatic plugin security releases. It isn’t a decision we make lightly. The WordPress.org security and plugins teams only want to make the web a safer place for you and your visitors.

 

FAQ

Q: Why did plugin A get a automatic update, but plugin B didn’t?

It’s not bias from WordPress.org, it’s just a throwback to the manual process we’ve been using. If we’re alerted to an issue, we’ll work to handle it. If we find out several days later, the window of opportunity to get the fix rolled out has usually passed and it won’t be as effective.

If any plugin authors reading this have recently issued a security update and would like us to consider pushing an automatic update for the remaining users, please get in touch with us and we’ll do whatever we can to help.

Q: I keep my plugins updated already and don’t wish to have plugin security updates pushed automatically. How can I disable them?

There are several options to disable this functionality. The previous article for disabling core automatic updates applies here. Anything that disables all automatic update functionality will prevent plugin updates.
If you only wish to disable plugin updates, whether for all plugins or a single plugin, you can do so with a single filter call. See this Codex article for more.

Q: If I discover a security issue in my plugin, what should I do?

Email plugins@wordpress.org to seek support from us. We’re here to help you. You should start working on a fix for the issue, and share a patch of the changes for review before you release it if you want us to review the change or if you think an automatic update could be needed.

Q: Will you ever push an automatic theme update?

One day, perhaps — but not until we can do this safely. This is a complicated problem to solve. We don’t currently have a way to verify whether a theme was edited to customize a site. We never want an update to break a site or lose customizations.

You can always enable automatic theme updates using the filters outlined in this Codex article. Also, the theme review team catches most issues long before the theme is available for download, making theme updates far less likely to be needed.

Q: How can I get involved with the plugins review team?

As the plugins team deals with very sensitive issues, it’s a small group of well-known, highly trusted community members. It’s grinding work with a seemingly never-ending queue. If you’re interested, email plugins@wordpress.org.

Q: How can the WordPress security team trigger a background update for a plugin?

The auto_update_plugin filter is run on a flag present in the plugins update API response. By default, the flag is false, but it can be specifically enabled for a plugin. Core and translation background updates use the exact same mechanism, the only difference being their API responses have the flag enabled by default.

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