Here is the main file download page for the IPS sensors.

Find the section for the version you are running and click on the Latest Signature Updates link to take to you to the download page for signature updates.

You can then download which ever signature update you want.

NOTE1: Each Signature Updates contains all signatures from previous Sig levels. So you only need to download the latest one.

NOTE2: Each signature update has a specific E (Engine) level requirement. You can execute "show ver" on your sensor to determine if it is at an E1 or E2 level. If it is at E1 and you want the latest sigs that require E2 then you will first need to install the E2 upgrade.

On that main download page look for the "Latest Upgrades" link for your version, and look for the IPS-engine-E2-req-X.X-X.pkg file where the X.X-X matches your sensor version.

If there is not an X.X-X matching your sensor version, then you may need to upgrade the software version for your sensor as well.

NOTE3: Many of these links will also require an account on cisco.com. And for some of these files that account may also need to be verified for being from a country where the USA's export restrictions allow downloads for encryption. (Most countries qualify but you do have to go through that qualification step). It has been over 10 years that I have had do this so I am not sure of the latest procedures for getting an account or validating it for encrpytion downloads.