Long story short, my friend has just cheated on her boyfriend. She is in an LDR for the past few months with her BF of 3 years. I have known her for a year and knew that she is the flirty-attention seeking type. I never suspected she would go that far in this case. She went on holiday and met up with an old acquaintance - she knew that she had a soft spot for him but met up anyway. What really annoyed me was how she gave me vague details of what happened which put me on her side (basically no mention of cheating, just that stuff went down). I found out from her other friends however that there was full blown cheating by her. I also found out that she has been drunkenly making out with guys in clubs for the past few months. Now she did confess to the BF about her cheating on the holiday and he broke up with her(I doubt she mentioned anything about the drunk sessions though). The problem was that she only did this a few days later - making it a confession for herself. Before the confession, she was actually snapchatting and posting photos on instagram with the guy himself while they were together under the pretext of reuniting as old friends.

Point is, this whole drama is just stuff that I do not need in my life. My question is this. Is it justifiable that I burn my friendship with her and just become Hi-Bye friends? We were quite close but I really don't want to be associated with people like her.

You don't need justification to 'burn' a friendship. The only time I might pass judgement is if your friend were down and out through no fault of her own, is all alone, and needs your help. Your friend doesn't need you and you don't need her.

Your details about her cheating are irrelevant. It's her life. You seem to be treading a fine line between just not liking her way of life vs. being judge and jury.

Its up to you how and why you make, and treat your friends. Not unusual at all for things to go sour as you get to know someone better. Happens all the time to all of us.