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Malwarebytes for Windows detected a Potentially Unwanted Modification
PUM.Optional.FireFoxSecurityOverride is Malwarebytes’ detection name for several potentially unwanted modifications (PUMs) in user.js, a Firefox browser configuration file, where the Safe Browsing feature is disabled or the viewing of mixed content is enabled in Firefox. As a result, users are made vulnerable to sites that may harbor insecure or potentially malicious content.
The following strings are modified in user.js:
From:
user_pref("browser.safebrowsing.enabled", true);
To:
user_pref("browser.safebrowsing.enabled", false);
From:
user_pref("browser.safebrowsing.malware.enabled", true);
To:
user_pref("browser.safebrowsing.malware.enabled", false);
From:
user_pref("browser.safebrowsing.downloads.enabled", true);
To:
user_pref("browser.safebrowsing.downloads.enabled", false);
From:
user_pref("security.mixed_content.block_active_content", true);
To:
user_pref("security.mixed_content.block_active_content", false);
Malwarebytes automatically sets the values of the modified strings in user.js to “true” to stop triggering the detection of PUM.Optional.FireFoxSecurityOverride.
When a Potentially Unwanted Modification (PUM) is detected on your computer, Malwarebytes for Windows does not know whether it was authorized. Optimization software, malware, and Potentially Unwanted Programs (PUPs) are known to make these types of changes, hence they are regarded as potentially unwanted by design.
To have Malwarebytes for Windows ignore a PUM, you must add the PUM to the Allow list. Here’s how to do it.
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