SHA-1 (Secure Hash Algorithm) is a cryptographic hash function produces 160-bit hash value, and it’s considered weak.

It’s quite interesting to know  – there are 93 % of a website is vulnerable to SHA1 on the Internet.

Google has started gradually sunsetting SHA-1 and Chrome version 39 and later will indicate visual security warning on websites with SHA-1 SSL certificate with validity beyond 1st Jan 2016.

Web Administrator is busy with so many vulnerabilities this year like Freak Attack, Heartbleed, Logjam. Well, that’s how Web Security is evolving, and one of the challenging tasks for Web Security Administrator would be to keep up-to-date on one’s knowledge and act wisely on security vulnerabilities to secure Web Applications.

In this article, I will talk about how to check for SHA-1 vulnerability and how you can fix this.

Test SSL SHA-1 bug

One of the quickest ways to test if your website SSL is signed with SHA-1 would be to hit the following URL and enter the URL and click on Go.



If it’s signed with SHA-1, you will get following dang


else you will get a nice message.


You may also check the following, which can help to check SHA-1.

Fix SSL SHA-1 bug

Fixing SHA-1 means you need to get an SSL certificate signed with SHA-2.

Some SSL cert providers can provide you a cert with SHA-2 signed, however, in most cases you would like to get the new SSL certificate signed and implement it.

To get SHA-2 certificate using OpenSSL

openssl req -new -sha256 -key example.key -out example.csr

You may also generate certificate online on the following:-

I hope now you know if your website SSL is SHA-1 signed and understood the procedure to fix this.