“Through a well-meaning but ultimately disasterous cleanup of OpenSSL’s randomness generation code, the Debian maintainer had inadvertently reduced the number of possible keys that could be generated by a given user from “bazillions” to a little over 32,000.”
For about 18 months Debian’s OpenSSL handed out predictable private keys. GitHub noticed in May 2008 when strangers with no link to each other turned up with the same SSH key fingerprint. Nobody had time to dig, so the hunt stalled until Luciano Bello’s advisory landed. Sixteen years later the XZ backdoor got caught the same way, by one person with spare time and a hunch. The industry’s security plan is still luck.