This type of hacking occurs when the user doesn't properly secure their own accounts.
Weak passwords, password reuse, falling for phishing scam and etc.
The user agent info collected shows the OS in use as well as the browser so the browser used doesn't impact the OS info.
Private browsing doesn't impact the collection of this info; it only prevents the browser from saving data from a browsing session.
That Netmarketshare data is relevant.
The Jailbreakme exploits could be leveraged via the browser and used in malware.
The other jailbreaks, including the untethered jailbreaks, start with a string of exploits that begin with a bootrom exploit. Bootrom exploits can't be leveraged directly from the browser so jailbreaks other than Jailbreakme are not applicable in malware.
Read the following article:
https://blog.duosecurity.com/2012/0...ay-over-50-of-android-devices-are-vulnerable/
Absinthe jailbreak starts with a bootrom exploit. See above for more info. I don't jailbreak.
iOS has the larger market share.
http://www.netmarketshare.com/operating-system-market-share.aspx?qprid=8&qpcustomd=
Android is an easier target.
https://blog.duosecurity.com/2012/0...ay-over-50-of-android-devices-are-vulnerable/
http://www.csc.ncsu.edu/faculty/jiang/pubs/OAKLAND12.pdf
http://www.zdnet.com/blog/hardware/millions-caught-up-in-android-botnet/17891
That represents only smartphone shipments/sales for one quarter.
It doesn't include tablet sales which are included in the same OS market share.
The following from the same link you provided represents the smartphone only market share but factor in the iPad and you get the numbers I provided.