Opera 73.0.3827.0 developer update

[ziegensatan]

ziegensatan @gmiazga last edited by

@gmiazga are there any news? if it is a false positive, it should be reported to microsoft
https://docs.microsoft.com/de-de/windows/security/threat-protection/microsoft-defender-antivirus/antivirus-false-positives-negatives

[gmiazga]

gmiazga Opera last edited by

Already reported and waiting for their response. Will update when I get more details.

[kened]

kened Banned @gmiazga last edited by

@gmiazga: The problem is that Opera was trying, insistently, to download these .dll files identified as threats by Windows Defender. In fact, I was prevented from uninstalling Opera by the conventional method.

[AndrewMills]

AndrewMills last edited by

Hi, in my new installation, every time I start Opera developer, Windows antivirus warns of a serious threat and appear this message...
https://ibb.co/zR3V45v

[leocg]

leocg Moderator Volunteer @AndrewMills last edited by

@AndrewMills See https://forums.opera.com/post/227355

[ghirahim]

ghirahim @gmiazga last edited by

@gmiazga: Thank you for your response. Much appreciated.

[burnout426]

burnout426 Volunteer @gmiazga last edited by

@gmiazga FWIW worth, I also submitted the dll for review as a false positive (and explained the situation and linked to threads about it) to Microsoft. See https://www.reddit.com/r/operabrowser/comments/j4ihvn/foxie_malware/g7ubuqi/?utm_source=reddit&utm_medium=web2x&context=3 for their response. Hopefully you have better luck.

[burnout426]

burnout426 Volunteer @kened last edited by

@kened said in Opera 73.0.3827.0 developer update:

In fact, I was prevented from uninstalling Opera by the conventional method.

In https://www.reddit.com/r/operabrowser/comments/j4ihvn/foxie_malware/g7s2mqv/?utm_source=reddit&utm_medium=web2x&context=3, I mentino how I had to kill some Opera processes to do some cleanup to get updating working again. I also had to do that to be able to uninstall Opera.

[kened]

kened Banned @burnout426 last edited by

@burnout426: I think we deserve a full explanation about what is happening. This is not normal.

[burnout426]

burnout426 Volunteer @kened last edited by burnout426

@kened What I know right now is that Windows Defender doesn't think it's malware or a virus. It just tags it as a potentially unwanted program. It's detected as BrowserModifier:Win32/Foxiebro. I can understand that as the Opera installer actions can and do modify Opera. So, it is indeed a "BrowserModifier", technically. The weird thing is it just started happening recently. I'm not sure if it's due to a definition update for Windows Defender where they have stricter rules or just a change (it'd be a safe change) in Opera's installer actions that triggers Defender now. And, remember. No other anti-virus does this.

If you're sure you don't have any real BrowserModifier:Win32/Foxiebro infections on your computer, you can allow the threat in Windows Defender until this gets sorted.

Reading the "Unwanted Software" section at https://docs.microsoft.com/en-us/windows/security/threat-protection/intelligence/criteria leads me to believe that Defender wants something in Opera's installer to be user-initiated in some way. Opera might just have to change something with one of its installer functions (when checking/doing updates etc.) to work around the detection and make Defender happy. But, we'll have to wait and see what Opera says.

[leocg]

leocg Moderator Volunteer @kened last edited by

@kened What is happening is that this time the antivirus giving, possibly, the false positive is one more widely used.

[kened]

kened Banned @burnout426 last edited by

@burnout426: I hope so.

[kened]

kened Banned @leocg last edited by

@leocg: I think it's a little more complicated than that.
I repeat: I was unable to uninstall Opera Developer. I had to remove all folders related to it. But I really hope it was just a false positive.

[kened]

kened Banned @leocg last edited by

@leocg: Probably, in the next few hours we will have a new build. We'll know better what's happening.

[gmiazga]

gmiazga Opera last edited by

Microsoft removed this detection. Their full reply:

We have removed the detection. Please follow the steps below to clear cached detection and obtain the latest malware definitions.

1. Open command prompt as administrator and change directory to c:\Program Files\Windows Defender
2. Run “MpCmdRun.exe -removedefinitions -dynamicsignatures”
3. Run "MpCmdRun.exe -SignatureUpdate"

Alternatively, the latest definition is available for download here: https://www.microsoft.com/en-us/wdsi/definitions

From our side there have been small changes in installer code on developer which probably got detected as malware together with Microsoft definitions update done on 2-3 October.

[kened]

kened Banned @gmiazga last edited by

@gmiazga: It's good to know that.

[kened]

kened Banned @gmiazga last edited by

@gmiazga: The procedure worked here. I'll wait for the next build to see what happens.

[burnout426]

burnout426 Volunteer @gmiazga last edited by

@gmiazga I made sure to remove the threat from "allowed threats" so that I can test if there's still a problem or not. All good so far after doing the commands. Opera Developer isn't trigger Windows Defender anymore.

[burnout426]

burnout426 Volunteer @burnout426 last edited by burnout426

@burnout426 However, if I right-click the Opera installer dll that I had saved and choose to scan it with Defender, it still detects the dll as being infected.

[tr3x]

tr3x @gmiazga last edited by

@gmiazga cool, thanks for resolving this

just for information, you have to run the commands like

.\MpCmdRun.exe -removedefinitions -dynamicsignatures
.\MpCmdRun.exe -SignatureUpdate

with '.' in the beginning because in another case you'll see 'The command MpCmdRun.exe was not found, but does exist in the current location' error

I executed the command, will monitor the further behavior