4 ms·
TLDR: I understand the author's sense of frustration, but I think DoS (including ReDoS) is trickier to handle than ignoring a class of vuln. Denial-of-service
by blincoln 4y ago
TLDR: I understand the author's sense of frustration, but I think DoS (including ReDoS) is trickier to handle than ignoring a class of vuln.
Denial-of-service vulnerabilities in general are something I usually find uninteresting, because in situations I'm likely to find myself in, they don't let me do anything I consider valuable.
I still typically report them, because I can imagine situations where this would definitely not be the case, e.g. if the organization using the product is under attack (time of war, protestors with a political goal, etc.).
Back when I was still in IT, I even experienced it once myself. Someone (apparently randomly) targeted the business I worked for with a massive UDP amplification DDoS. It was pretty eye-opening. The colocation facility they attacked literally would not take action (not even blocking a single destination port upstream) unless we paid extra for their anti-DDoS service.
ReDoS seems like something that's probably rarely useful to an attacker, but understanding the full scope can be challenging for a pen tester vs. the people who actually develop and use something, and so I err on the side of reporting something as a low/informational severity versus not reporting it at all. This is especially true if the vuln is in a library. We typically report library issues to whoever maintains the library, but that also means that most proofs of concept or exploitation scenarios are going to be less realistic than one where we show end-to-end exploitation in a full application.
Formula-based vuln scoring systems are inherently broken (IMO), but maybe one band-aid for this would be to have a separate score for any availability-related effects, to make it easier to filter out in situations where DoS isn't a significant concern.
- rtev 4y agoGreat take. Do you have any thoughts on how to improve on CVSS 3.1? I’m wondering if perhaps the optional “additional details” section, where you can contextually upgrade or downgrade scores, should be a mandatory part of the score.
- woodruffw 4y agoThe post specifically concerns ReDoS; I think DoS as a broader class has slightly more merit. (Ultimately, I don't care if people factor out accidentally exponential regular expressions -- that seems like a good thing to do! I take umbrage at the idea, however, that they're a vulnerability class that deserves the serious attention we give to things that attackers actually use. My perspective is that ReDoS reports are better suited for linting and CQA than they are for security reporting.)