Reaver is a WPA attack tool developed by Tactical Network Solutions and sold by Reaver Systems, LLC that exploits a protocol design flaw in WiFi Protected Setup (WPS). This vulnerability exposes a side-channel attack against Wi-Fi Protected Access (WPA) versions 1 and 2 allowing the extraction of the Pre-Shared Key (PSK) used to secure the network. With a well-chosen PSK, the WPA and WPA2 security protocols are assumed to be secure by a majority of the 802.11 security community.
WPS allows users to enter an 8 digit PIN to connect to a secured network without having to enter a passphrase. When a user supplies the correct PIN the access point essentially gives the user the WPA/WPA2 PSK that is needed to connect to the network. Reaver will determine an access point's PIN and then extract the PSK and give it to the attacker.
Current attacks against WPA networks involve the computation of rainbow tables based on a dictionary of potential keys and the name (SSID) of the network being attacked. Rainbow tables must be re-generated for each network encountered and are only successful if the PSK is a dictionary word. However, Reaver is not restricted by the limitations of traditional dictionary-based attacks. Reaver is able to extract the WPA PSK from the access point within 4 - 10 hours and roughly 95% of modern consumer-grade access points ship with WPS enabled by default.
Note: I'm not giving any support regarding this Reaver Pro version, I just found it and share with you.