Comment by tptacek
5 hours ago
I'm not saying that the vulnerability isn't severe or important to people running Wordpress, only that CVSS scores are literally a Ouija Board that can come out to whatever the user wants them to.
5 hours ago
I'm not saying that the vulnerability isn't severe or important to people running Wordpress, only that CVSS scores are literally a Ouija Board that can come out to whatever the user wants them to.
Yeah give me a vuln and I can make it anything between a 2 and 8 quite easily. I routinely see 10s that are "Critical 10.0 CVE (but only if you're using X language with X setting changed from default, and the attacker can MiTM your traffic)"
> CVSS scores are literally a Ouija Board that can come out to whatever the user wants them to.
Not really. They are very good at describing the technical impact. Sometimes pre-condition is very rare and that reduces overall likelihood but for those few it applies, the impact still could be catastrophic. Who wants to risk it if whole business could go down?
So if I get a 9.8 that doesn't apply to my usage, what is the CVSS score doing for me?
Published CVSS is a base score that gives you a hint of how important the analysis of a vulnerability is to prioritise the patching or mitigation. What you see on websites is only ever the base spiciness so to speak. If you have for example wordpress only running in an isolated environment behind internal firewall rules you‘d downgrade it accordingly. It’s a imperfect metric but so far the best we have to signal priorities. It’s all described in its spec that no one seems to read and websites also communicate it badly.
4 replies →
You need to reason about both probability and impact, not one or the other. In your example, it just means that the probability is very low, perhaps even down to 0 in your specific case. But even at a low probability, the impact of the vulnerability remains very high so it helps you reason about it.
For example, you might react differently to these scores:
- <8/10: check that your systems are indeed secure
- 8.6/10: check that your systems are indeed secure and tell your junior analyst to train on creating a custom monitoring rule for that attack and follow-up with you
- 9.8/10: double-check that your systems are indeed secure, ensure that if you had a hole another security layer would have caught it (if not, that's a problem!), set up a honeypot to get some info on the assholes that have repeatedly attacked you lately and will undoubtedly try to 0-day you in the next few hours, etc.