Authenticating with U2F

In order to further secure access to my workstation, after the switch to Gentoo sources, I now enabled two-factor authentication through my Yubico U2F USB device. Well, at least for local access - remote access through SSH requires both userid/password as well as the correct SSH key, by chaining authentication methods in OpenSSH.

Enabling U2F on (Gentoo) Linux is fairly easy. The various guides online which talk about the pam_u2f setup are indeed correct that it is fairly simple. For completeness sake, I've documented what I know on the Gentoo Wiki, as the pam_u2f article.

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Audit buffering and rate limiting

Be it because of SELinux experiments, or through general audit experiments, sometimes you'll get in touch with a message similar to the following:

audit: audit_backlog=321 > audit_backlog_limit=320
audit: audit_lost=44395 audit_rate_limit=0 audit_backlog_limit=320
audit: backlog limit exceeded

The message shows up when certain audit events could not be …

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Mitigating DDoS attacks

Lately, DDoS attacks have been in the news more than I was hoping for. It seems that the botnets or other methods that are used to generate high-volume traffic to a legitimate service are becoming more and more easy to get and direct. At the time that I'm writing this …

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