Edit: It's a CDN service hosted by Microsoft, IT'S NOT FOR MICROSOFT SITES ONLY, like some comments claim.
I try to keep CDN's blocked, but sometimes a site needs their CDN resources - if I trust the site, I have set NoScript to show not just the basedomain, but also the full DNS, so I can allow the specific CDN subdomain the site is using. In this case the site is "Have I been Pwned: Check if your email has been compromised in a data breach", and I trust them - but I needed one to check if a specific password have been leaked, for which I need to really trust the site if it needs to enter the password for search.... Such site could as well be collecting passwords :(
But yeah, keep the basedomain of ALL CDN's blocked, but consider on site basis if you could allow the subdomain their using.
I'm considering moving for my other privacy/security tool (which emphasises it's not an adblocker, though it's what's it's usually installed for). The first addon I install is Ad blocker, and because I'm not satisfied with AdBlock Plus (although I'd love to have the Acceptable Ad's support - I asked from µBlock Origin author, if adding the URL for the list would work. But only some of rules are compatible, and it would stop ALL other filters being applied - not just adblock ones... I considered forking and modifying it so, that you could mark what filter lists will be ignored if Acceptable Ad's list matched the site, but I dunno... And I'm considering moving to µMatrix (aka HTTP Switchboard), which seems like a cross between NoScript and µBlock Origin - they call it a firewall in browser. I think I'd like to have it, and it can block domains by base domain, so that for example you can have facebook.com/net, fbcdn.com, etc. otherwise, but have facebook.com as the site allowed and those other domains allowed there, which is nice (and if possible with NoScript, I have no idea how). It seems superb, but I think I'll still keep NoScript, but focus more on µMatrix on blocking and allowing. It also has, like Custom setting in NoScript, different things you can allow or block. This allows for example allowing these CDN subdomains only on site basis - so it's not globally allowed, in case some other site tried to wrongly use the same one.
Recommended: NoScript (configure to show more than just basedomain). µBlock Origin OR µMatrix if you're ready to read the simple guide for using it - it's really easy, but without guide it will confuse you beyond anything.
Also, maybe if you're not against ad's totally, but hate intrusive ad's, maybe set µBlock Origin/µMatrix to use only non ad-block filter lists, then install also AdBlock Plus (you can even add filter lists the former ones have for adblocking, but not all their rules are supported by ADB+, then enable Acceptable Ads.... But it's complicated and then you have two or three add-on for these things, when two (or even just µMatrix) is enough. Well, I also have Decentraleyes, which is good to have as well... But this ADB+ for ad's and µ* for non-adblock lists is kinda overworking. Besides, ADB+ has not as good filter rules in comparison, and the other options I've mentioned have superior graphical UI to select elements to block (like I removed a site hiding layer that was to do with paywall, and the site worked - wish it was that simple on all sites). But I have digressed...
"msecnd.net" domain name is empty. So no information about what they do. The name "msecnd.net" includes "cdn" which usually stands for "Content delivery network". The goal of CDN is to distribute service spatially relative to end-users to provide high availability and high performance. Read more at https://en.wikipedia.org/wiki/Content_delivery_network
This domain name is owned by the for profit corporation Microsoft Corporation. Source at https://gwhois.org/msecnd.net+dns
This domain name is used by https://answers.microsoft.com
Related question at https://answers.microsoft.com/en-us/feedback/forum/fdbk_commsite-bug/what-is-msecndnet/7cdd801f-949a-4734-a838-534a6a831f14?auth=1
During the last 7 days potentially active malware was detected on a subdomain. However, no threats were detected on the main website.
Malware Found: 4
Safety Rating: Caution
Compromised Pages: 93
These are the top viruses found on this site by the percentage of total detections they caused during the last 30 days.
1 Trojan horse Generic 88 %
2 DownloadAssistant 6 %
3 JS/Worm 2 %
4 MDAC ActiveX code execution 1 %
Last reported malware activity
Apr 08, 2016 (6 days ago)
Days with malware in last month
12 days (40% of total)
Days with malware in last year
165 days (45% of total)
Google’s Safe Browsing Site Status
Current status: Partially dangerous
Some pages on msecnd.net contain deceptive content right now.
Site Safety Details
***** Some pages on this website install malware on visitors' computers.
***** Attackers on this site might try to trick you to download software or steal your information (for example passwords, messages, or credit card information).
***** Some pages on this website send visitors to dangerous websites.
***** Dangerous websites have been sending visitors to this website, including: downfrefile.com, 5frefile.com, and anddownload.com.
Safety Scan Report
Malc0de ***** Alert
This site blocks access to the security scanner(s) shown below:
Cannot open site directly.
Partially dangerous: Some pages on msecnd.net contain deceptive content right now. Some pages on this website send visitors to dangerous websites. Some pages on this website install malware on visitors' computers. Attackers on this site might try to trick you to download software or steal your information (for example passwords, messages, or credit card information). Dangerous websites have been sending visitors to this website, including: anddownload.com, download366.com, and adnetworkperformance.com. We last updated our information about msecnd.net on March 6, 2016.
This is part of the Microsoft Network cloud based services (So reserved). It is also needed to access Skype Web page.
Reported on Virustotal by 2 companies as either malicious or malware. (https://www.virustotal.com/en/url/37b0982045cead2b8e63b0132c1264687b985c40a683436d1a3b3c4263854e37/analysis/1453119386/)
Google Safe Browsing shows this site as partially dangerous. (https://www.google.com/transparencyreport/safebrowsing/diagnostic/index.html#url=msecnd.net) Google reports links on the site DO install malware (As opposed to being directed to third party sites).
URLVoid reports a single contributor reporting this site as malicious (Malc0de.com) but when checked on that site, there was no listing. (http://malc0de.com/database/index.php?search=msecnd.net refers).
Whilst this site is needed to access substantial parts of MS Network Services, it should only be temporarily allowed as needed and only with a good firewall, antivirus and script blocker.
What happened when Google visited this site?
Of 9607 pages tested on the site over past 90 days, 8 page(s) resulted in malicious software being downloaded and installed without user consent. The last time Google visited this site was on 2015-08-07, and the last time suspicious content was found on this site was on 2015-08-02. Malicious software includes 10 virus, 10 trojan(s), 2 exploit(s).
This site was hosted on 2 network(s) including AS15133 (EDGECAST), AS15169 (GOOGLE).
Has this site acted as an intermediary resulting in further distribution of malware? Over the past 90 days, msecnd.net did not appear to function as an intermediary for the infection of any sites.
Has this site hosted malware? Yes, this site has hosted malicious software over the past 90 days.