There has been a resurgence in the Conficker worm (called W32/Confick) that we first saw in November. This is probably due to the malware authors adding some new propagation methods such as spreading via USB flash drives and Windows file-sharing. These techniques make it hard to remove from a network, as a single computer unpatched against the Microsoft MS08-67 security vulnerability, is able to reinfect the whole network via file shares. Make sure that Microsofts patch is in place on every vulnerable computer on your network.”]
Source: https://grahamcluley.com/stop-conficker-worm-unpatched-pc/