Seems to maybe be just a small subset of users who might have been infected, but this is scary.
Thankfully, it looks like this malware only affected a certain subset of CCleaner users. In particular, it affected:
- Users running the 32-bit version of the application (not the 64-bit version)
- Users running version 5.33.6162 of CCleaner or CCleaner Cloud 1.07.3191, released on August 15th, 2017
CCleaner is a popular tool that I know many techies have used to help clean up PCs for friends and family. Having it actually be the attack vector is a frightening proposition. How can a typical end-user investigate whether software they download is infected with malware or not?