iPhone Trojan Attack Warning I opened an internet radio app, HiDef Radio, that I have used before, many times, on my iPhone 4s with iOS 9.3. After connecting to a station and listening a short while, a window popped open saying:


  Apple Security
  Attention!!
  
  (6) virus detected on your iPhone!
  IP address 108.72.0.216 (not my iPhone's IP address)
  One of the last sites you've visited contained a Trojan, loading via the vulnerabilities of the browser.
  
  Click ok to start the cleaning process. After clean up, make sure to upgrade your system to the latest version.
  
  Install        Cancel
  
  Detected by Apple Firewall Ver 6.2.7


Clicking the Cancel button took my to the App Store for a VPN program, HotSpot Shield Free VPN Proxy which, as it turns out, I already have on my iPhone! But it was not running (and is not now, either) when the popup window appeared.

So what does all this mean? Obviously the popup is fake, there is no Firewall on iOS, the IP address is wrong, etc.

Is AnchorFree (makers of HotSpot) resorting to scare tactics to push their product?
Is the HiDef Radio app compromised?
These popups are completely and totally FAKE. All they're meant to do is prey upon your fears as a user. (tl;dr at the bottom)

Most app advertisements are networked, meaning the developer adds a little bit of code to their app, sets what kind of ads they want, and the network lets people buy ad slots. Sketchy ads (like these) pay a lot more, since they're banned from many networks and only some apps allow them (that's usually configurable).

These app advertisements are usually implemented as a custom WebView that only closes once the X appears after a few seconds. As you can see here, these ads also appear in safari, where you have to close the page, and cancel can do whatever the designers want it to do:



A lot of this style of ad also reference the "adult sites you've visited" hoping you won't turn to technical support or the Internet for help.

In reference to you saying that this was made by AnchorFree, that's highly likely. It's an easy (and sadly, effective) way of pushing their product to get more subscribers. Clicking download would've most likely taken you to the HotspotShield install page as well. Your HiDef radio app is probably fine.

tl;dr: your phone is fine, the ad is fake, and AnchorFree probably paid for it. The HiDef radio app is also fine.

PS: I'd be careful about the VPN apps you use, since some will sell your data that they gather through the tunnel they make to advertisers and other people. Read the privacy policy!