Variants of Win32/Pdfjsc may be encountered when visiting a compromised webpage with a vulnerable PC, or as an attachment to an email.
Downloads arbitrary files
If Win32/Pdfjsc successfully exploits a vulnerable computer, it may cause the Adobe application to crash, or it may attempt to download and install arbitrary files from a remote server. These downloaded files may be detected as malware.
Some of the vulnerabilities that variants of Win32/Pdfjsc have been known to exploit include:
Analysis by Shawn Wang and Methusela Cebrian Ferrer
Alerts from your security software may be the only symptom.