News: 1744719908

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ActiveX blocked by default in Microsoft 365 because remote code execution is bad, OK?

(2025/04/15)


Microsoft has twisted the knife into ActiveX once again, setting Microsoft 365 to disable all controls without so much as a prompt.

The change replaces the previous default setting, "Prompt me before enabling all controls with minimal restrictions," which relied on the user understanding the implications before blithely giving permission. Since ActiveX controls reach deep into the system, allowing them to run with "minimal restrictions" can open a user's system up to malicious folk and social engineering attacks.

[1]According to Microsoft : "The new default setting is more secure because it blocks these controls entirely, reducing the risk of malware or unauthorized code execution."

[2]

Getting ActiveX to work will require opening the Trust Center and re-enabling the prompt to allow controls. This assumes administrators have given users permission to access the ActiveX settings page.

[3]

[4]

ActiveX sprung from other Microsoft attempts at component-based engineering such as Object Linking and Embedding (OLE) and the Component Object Model (COM). The technology debuted last century and Microsoft deprecated it years ago.

It proved popular as a way to glue together Microsoft's productivity applications and creating corporate workflows, but it was also exploited to attack systems. [5]Drop a malicious ActiveX control into a document , convince a user to open it, and hey presto! Potential remote code execution!

[6]Windows Recovery Environment update fails successfully, says Microsoft

[7]Windows 11 stops freaking out over wallpaper customization

[8]Windows 2000 Server named peak Microsoft. Readers say it's all been downhill since Clippy

[9]Microsoft resets 'days since last Windows 11 problem' counter to 0

Therefore, Microsoft is making it progressively more difficult for users to enable ActiveX. Today's change [10]first turned up in Office 2024 LTSC and is now rolling out to Microsoft 365 subscribers.

However, the need for backward compatibility means ActiveX is still hanging around. Its potential replacements – such as the [11]Office Add-ins platform – can't fully match its capabilities while maintaining the same security posture. And many enterprises have decades of investment in code and processes built on ActiveX, making re-engineering a daunting task.

[12]

That said, the default setting in Microsoft 365 marks what may be the final step in Microsoft's journey to remove the technology once and for all from its productivity suite. After all, the company took the once unthinkable step of [13]deprecating VBScript in 2024 , flagging it for removal in a future version of Windows. ActiveX support appears to be on the same long overdue path. ®

Get our [14]Tech Resources



[1] https://techcommunity.microsoft.com/blog/microsoft365insiderblog/activex-disabled-by-default-in-microsoft-365/4403157

[2] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/front&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=2&c=2Z_6CrDQbt4g4drLco6_wJQAAAQw&t=ct%3Dns%26unitnum%3D2%26raptor%3Dcondor%26pos%3Dtop%26test%3D0

[3] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/front&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44Z_6CrDQbt4g4drLco6_wJQAAAQw&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0

[4] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/front&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33Z_6CrDQbt4g4drLco6_wJQAAAQw&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0

[5] https://www.theregister.com/2021/09/07/microsoft_office_zero_day/

[6] https://www.theregister.com/2025/04/15/winre_update_error/

[7] https://www.theregister.com/2025/04/14/windows_11_24h2_hold/

[8] https://www.theregister.com/2025/04/11/windows_2000_best_microsoft/

[9] https://www.theregister.com/2025/04/09/microsoft_resets_the_days_since/

[10] https://www.theregister.com/2024/09/18/microsoft_office_ltsc_2024/

[11] https://learn.microsoft.com/en-us/office/dev/add-ins/overview/office-add-ins

[12] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/front&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44Z_6CrDQbt4g4drLco6_wJQAAAQw&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0

[13] https://www.theregister.com/2024/05/23/windows_11_24h2_vbscript/

[14] https://whitepapers.theregister.com/



well

Anonymous Coward

outlook has been telling me for over a year that the teams plugin has been disabled as it's a security risk

so I'm presuming this might have something to do with it?

ActiveX?

heyrick

That's still a thing? Next you'll be telling me some important site still relies upon Flash...

Re: ActiveX?

Mentat74

Or Microsoft Silverlight...

Laughable security

itzumee

I recall developing an ActiveX control that was basically a drop-in component encapsulating the NNTP reader component of Outlook Express way back when. If my code implemented particular interfaces relating to security then my ActiveX control would basically be signalling itself as a safe and trustworthy control! Of course, I'm talking about unsigned ActiveX controls within an enterprise environment so there's a certain level of trust assumed but no-one checked what my code did and the NNTP reader control was just rolled out to anyone browsing a particular page on the company's intranet.

Embrace, Extend, Extinguish

ecofeco

M$ forced needless Active Cra-X on us for years and now, NOW says, oops our bad?

Triple E strikes again.

Microsoft... acknowledges shitty design?

John Klos

Microsoft is SO GOOD at reinventing a thing, poorly, with long term security issues. I don't know that professional programmers with that goal could make those kinds of problems on purpose.

It's good to see that they're capable, finally, of admitting when something is shitty. For how many decades did people have to endure macro viruses in documents JUST IN CASE someone might use macros and wouldn't want others to have to answer a prompt or something.

"You say there are two types of people?"
"Yes, those who separate people into two groups and those that don't."
"Wrong. There are three groups:
Those who separate people into three groups.
Those who don't separate people into groups.
Those who can't decide."
"Wait a minute, what about people who separate people into two groups?"
"Oh. Okay, then there are four groups."
"Aren't you then separating people into four groups?"
"Yeah."
"So then there's a fifth group, right?"
"You know, the problem is these idiots who can't make up their minds."