Its your friend, you dont know the detail
but me, i got VAC after hijacked
it was my new account, friend of mine (hacked also) send me a link to help, idk it wasnt him (it was the hacker) so i agree to open
thats how i lose my account and took Valve support 4 days to get it back to me
after i get it, i play Overpass and get 34 kill, after the game i got VAC Ban, i was like 'wtf ?'
then i check the game history and download the demo, the hacker play 3 match with blatant wallhack, 1 game he even goes further with 50kill and aimlock
i tell this to steam support, and also said that they must be know the fact bout the IP and my account is hijacked, they said..... VAC cant be removed