Someone discovered a vulnerability in Zabbix recently, and there’s this lovely, detailed description of an exploit based in it on Corelan Team. It’s lovely because it contains all the information I need to tell if my site is vulnerable, and to what extent.
There’s also a really useless advisory on Packet Storm Security. Why is it useless? Because at the bottom, there’s a section called Workaround, which reads ‘No workaround available’. This is really unfair to Zabbix:
Zabbix offers a mode called ‘active agent’, in which, rather than the server querying the agent, the agent submits information to the server periodically. This means it’s code on the monitored host that determines what information is passed to the server, and this eliminates the logical possibility of an escalation attack onto monitored hosts.
The existence of this mode is why I consider Zabbix in security sensitive applications. I pretty much assumed SQL injection attacks existed in Zabbix, because the API is written in PHP. Hence I wouldn’t consider using passive mode. I was a bit disappointed to find the guest account is enabled by default, but the point is, I know that Zabbix being compromised won’t result in a data protection incident.
So in short, the workaround is to disable passive agents: in your /etc/zabbix/zabbix_agentd.conf, set DisablePassive=1. But that’s what you were doing anyway, right? Zabbix deserve some criticism for providing a way of configuring their product that is not reliably secure, but I don’t think it’s too much to expect security researchers to have some awareness of the architecture of the products they publish security advisories about.
I should also point out that you could equally choose collectd, and graphite to get the same result. This has the added advantage that it’s the only way it works, so there won’t be any irrelevant security advisories to explain to your clients.
I don’t read either of the above sites regularly, so I don’t know if this single data point reflects the overall quality of either.