Quick answer:
Is NOT secure. SHA-1 was deprecated not only for being pretty easy for modern computers to brute-force (even more with the ASIC's developed for computing SHA operations), but for some mathematical weaknesses that made it more vulnerable and easier to break.
Read: https://en.wikipedia.org/wiki/SHA-1#Attacks
You can also read this article wrote IN 2012: http://arstechnica.com/security/2012/10/sha1-crypto-algorithm-could-fall-by-2018/
In which you see it was already considered weak, not by brute forcing, but by weakneses that make this algorithm easier to break (finding collissions is much easier than trying to brute-force).
By this year, many ASIC's (Application-Specific Integrated Circuit) have been developped to calculate SHA hashes quicker (mostly used for mining in cryptocurrencies as Bitcoin).