How to log into ASDM for a Cisco ASA when you get the Unable to launch device manager error

I like to keep my client’s devices up to date to prevent any issues from arising and have access to the devices latest features. Unfortunately not everyone is happy to pay that little extra to have an on-going support / maintenance agreement.  I was recently out at a customer who had an ASA 5505 which had been running for years but needed some new NAT translations added in.  So I fired up my laptop and loaded up ASDM Launcher, after typing in the credentials I got Unable to launch device manager on ASA-5505 error.  One thing I like to do when this happens is to check why, click on the Java icon in the login window and you will be prompted with the Java console, I saw the following;

javax.net.ssl.SSLHandshakeException: java.security.cert.CertificateException: Java couldn't trust Server
    at sun.security.ssl.Alerts.getSSLException(Unknown Source)
    at sun.security.ssl.SSLSocketImpl.fatal(Unknown Source)
    at sun.security.ssl.Handshaker.fatalSE(Unknown Source)
    at sun.security.ssl.Handshaker.fatalSE(Unknown Source)
    at sun.security.ssl.ClientHandshaker.serverCertificate(Unknown Source)
    at sun.security.ssl.ClientHandshaker.processMessage(Unknown Source)

java_securityThe main thing sticking out to me was Java couldn’t trust Server to fix this I needed to load up the Java control panel once open navigate to the Security tab > Edit Site List… > Add > Enter the URL of ASDM.  In my case that was https://192.168.1.254/ once I added that, click Ok and Apply and close out of your browser / ASDM Launcher.  Now if you try to log in again it should let you through into ASDM and allow you to make the changes you need.

Another method to resolve this error is to export the certificate of the device to your computer (use firefox and navigate to the appliance web page and export the SSL certificate) then import it into Java using the control panel method above but hit Manage Certificates…

If you’re running a new version of ASDM, this doesn’t happen, also some say downgrading Java to 1.6 will remove the issue also.  Hope that helps someone out.

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