
Hi all, as you may know, there is a "quadRooter" exploit for most of the available Android devices. https://www.checkpoint.com/downloads/resources/quadRooter-vulnerability-rese... Among others, it is possible to exploit because it is possible to disable SELinux (page 10) After years of using FreeBSD and securing them, I was astonished when I saw someone disabling SELinux the first time. How could that be? I am used to securelevels in FreeBSD, see security(7), https://www.checkpoint.com/downloads/resources/quadRooter-vulnerability-rese... The kernel runs with five different security levels. Any super-user process can raise the level, but no process can lower it. chflags(1) is used to harden access to files, with securitylevel 1 or higher it is not possible to alter them neither (in contrast to SELinux where I can change the security contexts of files on a running SELinux hardened system) The current exploit is a fine example why this kind of approach is needed. No process should be able to disarm a hardened system. Linux containers do not seem to give too much additional security, so it is always recommended to use SELinux to increase the security.. It sometimes feels like a "better than nothing" trap, giving the false sense of security. Should SELinux be reworked so that disarming is not possible? Regards Peter

On Monday, 8 August 2016 11:50:50 PM AEST Peter Ross via luv-main wrote:
After years of using FreeBSD and securing them, I was astonished when I saw someone disabling SELinux the first time. How could that be?
I am used to securelevels in FreeBSD, see security(7),
https://www.checkpoint.com/downloads/resources/quadRooter-vulnerability-rese arch-report.pdf
The kernel runs with five different security levels. Any super-user process can raise the level, but no process can lower it.
The PDF file you cite describes how a lack of kernel address space randomisation permits exploiting the kernel. If the BSD kernel is compiled without such kernel protections then similar attacks could be performed against it. The PDF describes changing UID to 0, any code that can do that can change secure levels. -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/
participants (2)
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Peter Ross
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Russell Coker