OS X 10.8.4 isn't showing any updates via the App Store or the command line softwareupdate tool. How can I make it start showing updates as usual again?
Edit:
sudo softwareupdate -l outputs "No new software available."
In Console, App Store logs
storeagent[205]: CKSoftwareMap: updateRequestBodyData:includeInstalledApps:includeBundledApps:conditionally:hadUnadoptedApps:waitUntilMapIsLoaded: timed out waiting for mdSemaphore
and softwareupdate logs
storeagent[205]: CKSoftwareMap: _expectedMetadataChangeTimeout: timed out waiting for mdSemaphore
install.log shows
Software Update[7145]: Failed Software Update - trust evaluation failed in SecTrustEvaluate with result: 3
Software Update[7145]: Can't load distribution from https://swdist.apple.com/content/downloads/60/30/041-5397/SPKMyGZ5qPWksQfvZHYwfhTRdB6HHsSjGn/041-5397.English.dist.gz: Host cert invalid or otherwise insecure download
Best Answer
As it turns out Apple's swdist.apple.com domain uses a certificate from COMODO and that CA has been untrusted on this computer. Trusting it again worked but is distasteful[1].
[1] http://en.wikipedia.org/wiki/Comodo_Group#2011_breach_incident