Logging software program has made cyberinsecurity headlines many occasions earlier than, notably within the case of the Apache Log4J bug referred to 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 methods let you write what virtually quantity to “mini-programs” proper in the midst of the textual content that you simply need to log, so as to make your logfiles “smarter” and simpler to learn.
For instance, for those who requested Log4J to log the textual content I AM DUCK, Log4J would do exactly that.
However for those who included the particular markup characters ${...}, then by selecting rigorously what you inserted between the squiggly brackets, you possibly can pretty much 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 correct form of booby-trapped knowledge for a server to log, comparable to a sneakily constructed e mail tackle or a faux surname, you possibly can perhaps, simply perhaps, ship program instructions to the logger disguised as plain outdated textual content.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 safety gap in VMWare’s Aria Operations for Logs product (AOfL, which was once referred to as vRealize Log Perception).
The unhealthy information is that VMWare has given this bug a CVSS “safety hazard” rating of 9.8/10, presumably as a result of the flaw may be abused for what’s referred to 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above, and it means precisely what it says: a distant attacker can ship over a bit of what’s speculated to be plain outdated knowledge, however that finally ends up being dealt with by the system as a number of programmatic instructions.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 trend of their very own selecting, virtually as if they’d phoned up a sysadmin and mentioned, “Please login utilizing your personal 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 will inform, is that the bug can’t be triggered just by abusing the logging course of through booby-trapped knowledge 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 companies really run.
We’re assuming that almost all networks the place AOfL is used don’t have their AOfL companies 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 massive.
That’s much less dramatic than Log4Shell, the place the bug might, in principle a minimum of, be triggered by community site visitors despatched to virtually any server on the community that occurred to utilize the Log4J logging code, together with methods comparable to net servers that have been speculated to be publicly accessible.
What to do?
- Patch as quickly as you may. 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 referred to as VMware Cloud Basis model 4.x, which wants updating to model 4.5 first, after which upgrading to VMware Aria Operations for Logs 8.12.
- Should you can’t patch, minimize down entry to your AOfL companies as a lot as you may. Even when that is barely inconvenient to your IT operations workforce, it may well significantly cut back the chance {that a} criminal who already has a foothold someplace in your community can attain and abuse your AOfL companies, and thereby improve and prolong their unauthorised entry.
