Hi cat1092, i can't quote you, but it'd be interesting to understand more fully how Yahoo Fantasy Sports infects a computer and how the infection spreads via router, in laypersons terms ...
MajesticFailure, to Beeping Computer Forums!
We're glad to have you hear & hope that you'll find our forum meets your needs.
Now, to answer your question. If you were to examine the Am I Infected line closely, and read all of the posts, you may be surprised (or not?) to find that many has one or more has visited Yahoo sites, clicked onto a legit looking link on the page, and the Malware begins to flow. That person, nor anyone else on the network, may not know, until the damage is done, there's no turning back, other than pressing the power key to (hopefully) prevent damage or spread to one's Data & Recovery partitions. Many Malwares will disable Recovery & sneak in there, so even if a recovery could be forced with a partition tool by making it Active & rebooting, to reload the OS, it's no longer safe.
Nor is one's data. One has to use a bootable tool, such as a Linux distro, and pull any wanted files, photos, emails, whatever out, and scan multiple times using more than one product to ensure these are 'clean'.
As to Yahoo Fantasy Sports in general, well that's what the person was on while two of my Windows 7 installs were infected within minutes, not to include the loaner computer. While I had backups of all, and was able to swiftly restore the entire drives of all, an in the 15% of of Home users who performs this task, and I perform weekly full disk images, none of that incremental stuff, which is more prone to failure.
The thing about Yahoo (& AOL until Version took the corporation in), that they have little choice in screening those looking to place ads on their site, like Outlook/Hotmail, GMail, and the bigger names of today which has no cash flow issues. And when one is desperate for cash, will often turn their heads even if they know of possible bad intent. Once they lease that ad space, it's on, it's either let the ads continue, or pay back any upfront cash paid, and Yahoo simply cannot afford that option with a CEO on the verge of collecting a $55 million 'golden parachute' who could care less. The site was once cleaned up for 2-3 months, only to fall back to the dogs under her watch in both instances.
So with this explanation, I hope that this answers your question.
In the meantime, have once again rethought my 'guest plan' for lending a notebook, will have no other choice but to either set things up in my PC room to be viewing the same page as they & have emergency control of the keyboard/mouse, go back to my old plan and allow all the use of my XP notebook only to discourage asking for a computer (can always say the Toshiba is 'in need of repair'), and will use the 'guest' network of my router, which is separate from my connection & won't cause infections to any connected to the main network (which I didn't have at the time), or finally choking access to all others on my network (probably best option). Since most has both a smartphone plus a notebook or tablet, am not dumb, know there's a way to make most any modern smartphone a 'hotspot' for computer use at full 4G speed for up to 10GB (some has this capped at 5GB), if any lower than 5GB, time to get another plan.
Walmart (teamed with T-Mobile) has a $30 promo every 2-3 months that allows up to 4GB of 4G content per month, with 'all you can eat' 3G afterwards. Some being freeloaders, why would someone owning an iPhone need to borrow one's notebook for? Many will use Windows notebooks when free, yet won't pay for one, and this applies to the guest in question, he not long back stated that only Apple computers were 'secure enough' for his usage. Having lost a rather prestigious job about 8-9 years back due to viewing adult content on company computers (as well as possibly his marriage, which fell apart less than a couple of months later with a less than 6 moth old daughter), he ought to know more about security by now, called 'network auditing'. Took him close to 5 years to regain a respectable job again, so hope that he learned a lesson on that front, yet there's obviously lots of room for improvement.
A Firewall appliance is yet another option, Sophos has one free for private use, and I have a spare PC that meets the requirements, other than an outbound Gigabit card, which can be picked up for $25 or less on eBay, Intel branded ones that over $300 new back at the time of W7's release.
Because even if I were to add Yahoo.com (and all sub-sites), as well as Facebook, Twitter, Amazon, NC Dept of Revenue & the IRS onto the hosts file, someone will have another, Yahoo's not the only sleazy, Malware loaded site on the Internet, and before all is said & done, the list will be so long hat it'll require copy/pasting to Notepad the list of sites to save.
The reason why I was able to iD the malicious sites were due to an AdwCleaner report of the computer that I allow guests to use, as well as extensive browsing history left behind. Most every site visited were Yahoo.com ones, along with a few Facebook one at the end of session, however that was after the infections took place. MBAM also tried to block access to sites which was overridden, now has password protection.
Some folks just never learns............until they end up in prison for doing something stupid.
One thing's for certain, there's no 'get out of jail free' cards here.
Edited by cat1092, 21 May 2016 - 03:35 AM.