Where does Ubuntu store the SSL certificates for Pidgin?

Solution 1:

They're stored here:

~/.purple/certificates/x509/tls_peers/

I've seen that replacing omega.contacts.msn.com's content with this fixes it for me (warning: there could be security implications for this):

-----BEGIN CERTIFICATE-----
MIIGeDCCBWCgAwIBAgIKfdrgSQAIAAHIuTANBgkqhkiG9w0BAQUFADCBizETMBEG
CgmSJomT8ixkARkWA2NvbTEZMBcGCgmSJomT8ixkARkWCW1pY3Jvc29mdDEUMBIG
CgmSJomT8ixkARkWBGNvcnAxFzAVBgoJkiaJk/IsZAEZFgdyZWRtb25kMSowKAYD
VQQDEyFNaWNyb3NvZnQgU2VjdXJlIFNlcnZlciBBdXRob3JpdHkwHhcNMTAxMTE1
MjEyODE5WhcNMTIxMTE0MjEyODE5WjB2MQswCQYDVQQGEwJVUzELMAkGA1UECBMC
V0ExEDAOBgNVBAcTB1JlZG1vbmQxDDAKBgNVBAoTA01TTjEdMBsGA1UECxMUTVNO
IENvbnRhY3QgU2VydmljZXMxGzAZBgNVBAMMEiouY29udGFjdHMubXNuLmNvbTCC
ASIwDQYJKoZIhvcNAQEBBQADggEPADCCAQoCggEBAJnXhdENETaZ8YFfenWCuky3
Fke/oWgUOEbgvaRuZusd2LnvoSiqH++2lkV0JJlIQ+7jLLN8MY7VhlHQmkLC3x44
KZn2IktMVgTBGMKnvbyYVAnRsjt/rVhQrQeHVEQzv5WXx//3FKmXWAuJiuRj9PZ2
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AQoGA1UdHwSCAQEwgf4wgfuggfiggfWGWGh0dHA6Ly9tc2NybC5taWNyb3NvZnQu
Y29tL3BraS9tc2NvcnAvY3JsL01pY3Jvc29mdCUyMFNlY3VyZSUyMFNlcnZlciUy
MEF1dGhvcml0eSg4KS5jcmyGVmh0dHA6Ly9jcmwubWljcm9zb2Z0LmNvbS9wa2kv
bXNjb3JwL2NybC9NaWNyb3NvZnQlMjBTZWN1cmUlMjBTZXJ2ZXIlMjBBdXRob3Jp
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TQYIKwYBBQUHMAKGQWh0dHA6Ly9jb3JwcGtpL2FpYS9NaWNyb3NvZnQlMjBTZWN1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-----END CERTIFICATE-----

Solution 2:

Have you taken a look at this guide already: Fix the Pidgin ‘SSL Error’ in Ubuntu [OMG!Ubuntu!] ?

From the aforementioned post:

1. Open https://omega.contacts.msn.com in your browser
2. You will get a directory access denied error - for once it’s what we want to see!
3. Click the ‘security’ or ‘padlock’ icon usually found to the left of the URL in the address bar to view the certificate.
4. Click around to find the ‘export certificate’ feature (In Chrome/ium this is the ‘details’ tab)
5. Rename the exported certificate omega.contacts.msn.com and copy it to the Pidgin certificates folder located in your home folder at .purple\certificates\x509\tls_peers\ (You’ll need to press CTRL+H to see hidden files)
6. Overwrite the existing file with the one you’ve just exported
7. Breathe. You’re done.

Solution 3:

in pidgin select 'Certificates' from 'tools' menu. Here you can manage ssl certificates. Just delete the old one and click on the 'add' button to create a new one, select the new certificate file which you have exported from the website. Give a suitable name and click ok. Thats it. you are done.