[Dshield] More secure default configurations?

Miles Stevenson miles at mstevenson.org
Fri Mar 18 18:43:09 GMT 2005

I just read a Security Focus article that has been gaining a bit of attention 
on Slashdot recently, titled "Linux Kernel Security, Again", by Jason Miller. 
In the article, Jason shares his opinion about Linux distributions not coming 
with more secure default settings, in this case default ulimit settings for 
number of allowed processes. The article can be found at: 

But who's responsibility is it to secure a computer system? Is it the OS 
vendor? The individual application vendors? The reseller? Or perhaps, the 
user maybe? 

I don't care if you are selling a proprietary OS such as Windows, or an open 
source system like RedHat or SuSe, you are still subject to the economics of 
supply and demand. If you want people to use your OS (whether you want to be 
paid for it or not), you have to respond with what they want. 

As infosec professionals and enthusiasts, we understand the value in the 
principle of least privilege. We know that from a security standpoint, it is 
a good idea to restrict users as much as possible in order to keep their data 
secure. But those of us who end up having to deal with such users directly 
(such as sysadmins and support staff) know all too well that users do not 
like being restricted. I think vendors know this too. 

At my company, it is my responsibility to properly secure the systems that I 
build. If a user were to launch a successful forkbomb attack against one of 
our systems, it would be the sysadmin's responsibility to set the proper 
ulimit on the machine, not the OS vendor. 

Even personal desktops running Windows XP are ultimately the responsibility of 
the owner. It is my responsibility to implement the appropriate security 
controls for my web surfing needs. It is my decision if I want to enable 
automatic logon as an Administrator or not, not Microsofts.

Instead of trying to persuade and inform users how to better secure their 
systems, the security professionals such as Jason Miller blame the OS vendors 
for not being secure enough, who in turn implements more restrictive default 
security controls, who in turn gets blamed by the majority of the user 
community for their product not being very intuitive and easy to use.

I realize that setting more restrictive ulimit settings by default probably 
won't impact the majority of users. I agree that it would be a good idea to 
have more restrictive default ulimit settings by default. But my point is 
that this case illustrates a reaction from the security community that I 
think is understandably instinctive, but misguided: software vendors need to 
start tightening up their default settings to be more restrictive. It's easy 
for us to ignore the impact this will have on the user market, but not the 

All software should have the capability to be properly secured. Writing secure 
code and offering security functionality is the responsibility of the OS 
vendor. But configuring the security of a computer system appropriately is 
the responsibility of the system owners. Instead of blaming OS vendors for 
not implementing more secure default security configurations, how about 
persuading users that they should want more restrictive but secure 
configurations? If the majority of users demand (actually desire) more secure 
configurations of their systems, the laws of supply and demand will ensure 
that vendors will respond.

Miles Stevenson
Email: miles at mstevenson.org
URL: http://www.mstevenson.org
PGP/GPG Key ID: 329F889D767D2F63

More information about the list mailing list