Mar 27, 2026 - For details about updated CVE-2025-53521 (BIG-IP APM vulnerability), refer to K000156741.

Forum Discussion

TMcGov_92811's avatar
TMcGov_92811
Icon for Nimbostratus rankNimbostratus
Dec 08, 2008

iRule to log SSL failures due to weak encryption

I have implemented the following Ciper in an SSL profile per F5 support to prevent SSLv2 or weak encryption schemes from connecting.     ALL:!NULL:!ADH:!LOW:!EXP:RC4+RSA:!SSLv2:+HIGH:+MEDIU...
application delivery
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devops
irules
hoolio's avatar
hoolio
Icon for Cirrostratus rankCirrostratus
Dec 08, 2008
To add to Denny's suggestion, you could set no restrictions on the client SSL profile, but then check the cipher bits and/or name in an iRule in HTTP_REQUEST. If the client's SSL spec is too low, you could send back a response or redirect. Here are a couple of related posts:

 

 

HTTPS Redirects (Click here)

 

 

Identify Client Cipher Strength (Click here)

 

 

Aaron