Firefox Blocks Malicious Extensions ByPass And ByPass XM

Mozilla is pulling the plug on some add-ons after it was discovered that they abuse APIs and – among other things – block Firefox updates. These are popular extensions that together have nearly half a million users.

This is reported by the online magazine Bleeping Computer. The add-ons now banned are Bypass and Bypass XM, two extensions that bypass the paywall. According to the report, to ensure this function, an interface was used to intercept and redirect web requests. However, this also prevented users from downloading updates, updating remotely configured content, and accessing updated block lists.

Interface is now blocked

Mozilla has blocked these browser extensions, now classified as malicious add-ons, which were previously installed by around 455,000 users. An investigation by Mozilla went ahead after it was discovered in early June that Bypass and Bypass XM are abusing the proxy API to block Firefox updates.

“To prevent additional users from being affected by new add-on submissions that abuse the proxy API, we’ve paused approvals for add-ons that use the proxy API until fixes are available to all users “, explained Rachel Tublitz and Stuart Colville from Mozilla the matter.

“Starting with Firefox 91.1, Firefox now includes changes to use direct connections when Firefox makes an important request (e.g. for updates) through a proxy configuration that fails. Ensuring that those requests complete successfully helps we are in the process of providing our users with the latest important updates and protective measures, “the Mozilla managers continued. To block similar malicious add-ons that abuse the same API, Mozilla has now added a system add-on (hidden in the ‘about: addons’ UI, impossible to disable and upgradeable without rebooting) called Proxy Failover.