Tampermonkey Chrome Extension Blacklisted by the popular Web Browser Opera

Chrome Web Store is facing an uphill battle from the last few years for hosting malevolent add-ons that claim to enhance your web browser capabilities.

Tampermonkey, the widely used free browser extension known to manage user scripts & offer valuable features to improve user’s browsing experience has been declared malicious by the infamous Opera web Browser. So if you have installed Tampermonkey 4.7.54 extension from Chrome web Store in Opera Browser & using it, you will be alerted by the warning:

Opera has blacklisted one of your extensions, and we’ve blocked it for your safety. Go to the extensions manager for more details

The popular user script manager extension, Tampermonkey has over 10 million users & is available for all the popular browsers including Chrome, Safari, Opera, Firefox & Microsoft Edge. The distinctive attributes offered by the extension include:

1. Clear Overview over the running scripts.
2. ZIP- based import & export
3. A built-in editor
4. Automatic Update checks
5. Browser & Cloud Storage based synchronization

Opera revealed that it discovered a malware installing the version of Tampermonkey found on the Chrome web Store with extension ID dhdgffkkebhmkfjojejmpbldmpobfkfo. The malware was spread using alternative distribution option depicting that the extension was being installed manually via the JSON or registry.

If you visit Opera’s extension manager to know the reason for Tampermonkey’s removal, it reveals that the extension has been blocked by Opera as it is malicious and informs the user to either leave or remove it.

On the contrary, if you downloaded the extension from Opera Store you will have no problem because it hosts the older version of the extension i.e. 4.2.5291.

This explains the reason why users prefer installing Tampermonkey from Chrome web store for Opera browser despite its availability in Opera add-ons site as the extensions are frequently updated by developers in Chrome Web Store. The popularity of Chrome Web Store makes it the most preferred app store to install extensions.

Tampermonkey is not necessarily a malicious browser extension as it does not affect computers. However, when Chrome Web Store version of Tampermonkey is installed with other unknown programs it may cause havoc. Such suspicious programs utilize an extension like Tampermonkey to facilitate the ads injection or modify search behavior in browsers.

This makes it a bit confusing to discover if Tampermonkey is a real virus, or is being misused by malicious programs for malevolent activities.

Hence if the legitimate browser extension is blacklisted by Opera because it is leveraged by threat actors for malicious purposes you can re-enable the blacklisted Tampermonkey Chrome extension in Opera by following these steps:

1. Close Opera browser
2. Type Run in the Search Box and press Enter.
3. Open the following file by entering: %UserProfile%\AppData\Roaming\Opera Software\Opera Stable\Preferences in the Search Box.
4. Choose open with > Notepad to open the file in Notepad
5. Search for the extension ID dhdgffkkebhmkfjojejmpbldmpobfkfo in the file.
6. Set “blacklist”:true to “blacklist”:false and change “blacklist_state”:1 to “blacklist_state”:0
7. Save the Preferences file & close it.
8. Now launch Opera & visit Extension Manager. You will find activated Tampermonkey Hence Tampermonkey will be working again.

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