There are plenty of articles offering guidance on preventing or dealing with ransomware, but this one has a good list of decryption tools, so well worth a look.
Ana Dascalesu for Heimdal: Ransomware Decryption Tools – Unlock Your Data for Free
“These free tools will help you decode your data without paying the ransom”
Wannacry in-memory key recovery for WinXP – Adrian Guinet warns:
“This software has only been tested and known to work under Windows XP. In order to work, your computer must not have been rebooted after being infected.
Please also note that you need some luck for this to work (see below), and so it might not work in every cases!”
However, wanakiwi claims to have tested it successfully with versions up to Windows 7, but points to some alternative information. WannaCry — Decrypting files with WanaKiwi + Demos
Dan Goodin for Ars Technica: Windows XP PCs infected by WCry can be decrypted without paying ransom – “Decryption tool is of limited value, because XP was unaffected by last week’s worm.”
John Leyden for The Register: There’s a ransom-free fix for WannaCrypt. Oh snap, you’ve rebooted your XP box – “Sooo… that’s not gonna work for you mate”
I see there is much excitement in the media about CryptXXX’s ‘Christmas discount’, the ransom having been reduced from 1.2 bitcoin to 0.5 until the end of December. Of more significance is the fact that Kaspersky have once more been able to update their Rannoh decryptor to handle CryptXXX version 3. Available from directly from Kaspersky or from NoMoreRansom.org.
Commentary from The Register – Don’t pay up to decrypt – cure found for CryptXXX ransomware, again – and from SC Media, in an article with some interesting commentary from industry stalwarts such as Anton Ivanov and Paul Ducklin, even though most of the story is about the ‘discount’.