Why does WEP cracking fail?
Recovery of a WEP key can fail for a few reasons. The most common reason is that a valid ARP packet was not captured. If there are no associated and active clients on the wifi network then you wont be in a position to capture an encrypted ARP packet (due to a lack of traffic) to use the in the replay attack. SILICAU attempts to de-authenticate clients in hopes to force an ARP. If this fails then you will have to wait passively until an ARP is generated by a wireless client. SILICAU will wait indefinitely for this traffic in the latest version. It is also possible that you collected an ARP from a client that wants to learn the address of a host that is no longer active/connected on the network. If this is the case SILICAU will send the request but not receive a reply and will only collect unique IVs passively from other traffic on the network. Another reason could be that the AP has protection against this type of attack.
