Logging software program has made cyberinsecurity headlines many instances earlier than, notably within the case of the Apache Log4J bug often known as Log4Shell that ruined Christmas for a lot of sysadmins on the finish of 2021.
The Log4Shell gap was a safety flaw within the logging course of itself, and boiled right down to the truth that many logfile techniques let you write what nearly quantity to “mini-programs” proper in the course of the textual content that you simply wish to log, as a way to make your logfiles “smarter” and simpler to learn.
For instance, if you happen to requested Log4J to log the textual content I AM DUCK, Log4J would do exactly that.
However if you happen to included the particular markup characters $..., then by selecting rigorously what you inserted between the squiggly brackets, you can nearly as good as inform the logging server, “Don’t log these precise characters; as a substitute, deal with them as a mini-program to run for me, and insert the reply that comes again.”
So by selecting simply the precise kind of booby-trapped information for a server to log, akin to a sneakily constructed electronic mail handle or a faux surname, you can perhaps, simply perhaps, ship program instructions to the logger disguised as plain previous textual content.
As a result of flexibility! As a result of comfort! However not as a result of safety!
This time spherical
This time spherical, the logging-related bug we’re warning you about is CVE-2023-20864, a security hole in VMWare’s Aria Operations for Logs product (AOfL, which was often known as vRealize Log Perception).
The dangerous information is that VMWare has given this bug a CVSS “safety hazard” rating of 9.8/10, presumably as a result of the flaw might be abused for what’s often known as distant code execution (RCE), even by community customers who haven’t but logged into (or who don’t have an account on) the AOfL system.
RCE refers to the kind of safety gap we described within the Log4Shell instance above, and it means precisely what it says: a distant attacker can ship over a piece of what’s presupposed to be plain previous information, however that finally ends up being dealt with by the system as a number of programmatic instructions.
Merely put, the attacker will get to run a program of their very own alternative, in a style of their very own selecting, nearly as if they’d phoned up a sysadmin and mentioned, “Please login utilizing your individual account, open a terminal window, after which run the next sequence of instructions for me, with out query.”
The excellent news on this case, so far as we are able to inform, is that the bug can’t be triggered just by abusing the logging course of through booby-trapped information despatched to any server that simply occurs to maintain logs (which is just about each server ever).
As a substitute, the bug is within the AOfL “log perception” service itself, so the attacker would wish entry to the a part of your community the place the AOfL providers truly run.
We’re assuming that the majority networks the place AOfL is used don’t have their AOfL providers opened as much as anybody and everybody on the web, so this bug is unlikely to be instantly accessible and triggerable by the world at giant.
That’s much less dramatic than Log4Shell, the place the bug might, in principle at the least, be triggered by community visitors despatched to nearly any server on the community that occurred to utilize the Log4J logging code, together with techniques akin to net servers that had been presupposed to be publicly accessible.
What to do?
- Patch as quickly as you possibly can. Affected variations apparently embody VMware Aria Operations for Logs 8.10.2, which must be up to date to eight.12; and an older product flavour often known as VMware Cloud Foundation version 4.x, which wants updating to model 4.5 first, after which upgrading to VMware Aria Operations for Logs 8.12.
- If you happen to can’t patch, minimize down entry to your AOfL providers as a lot as you possibly can. Even when that is barely inconvenient to your IT operations group, it might probably tremendously scale back the chance {that a} criminal who already has a foothold someplace in your community can attain and abuse your AOfL providers, and thereby improve and lengthen their unauthorised entry.
