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'Most Serious' Linux Privilege-Escalation Bug Ever Is Under Active Exploit (arstechnica.com)
Reader operator_error shares an ArsTechnica report: A serious vulnerability that has been present for nine years in virtually all versions of the Linux operating system is under active exploit, according to researchers who are advising users to install a patch as soon as possible. While CVE-2016-5195, as the bug is cataloged, amounts to a mere privilege-escalation vulnerability rather than a more serious code-execution vulnerability, there are several reasons many researchers are taking it extremely seriously. For one thing, it's not hard to develop exploits that work reliably. For another, the flaw is located in a section of the Linux kernel that's a part of virtually every distribution of the open-source OS released for almost a decade. What's more, researchers have discovered attack code that indicates the vulnerability is being actively and maliciously exploited in the wild.
"It's probably the most serious Linux local privilege escalation ever," Dan Rosenberg, a senior researcher at Azimuth Security, told Ars. "The nature of the vulnerability lends itself to extremely reliable exploitation. This vulnerability has been present for nine years, which is an extremely long period of time." The underlying bug was patched this week by the maintainers of the official Linux kernel. Downstream distributors are in the process of releasing updates that incorporate the fix. Red Hat has classified the vulnerability as "important."
"It's probably the most serious Linux local privilege escalation ever," Dan Rosenberg, a senior researcher at Azimuth Security, told Ars. "The nature of the vulnerability lends itself to extremely reliable exploitation. This vulnerability has been present for nine years, which is an extremely long period of time." The underlying bug was patched this week by the maintainers of the official Linux kernel. Downstream distributors are in the process of releasing updates that incorporate the fix. Red Hat has classified the vulnerability as "important."
Can I use this to root my Android phone? I just want to install an ad-blocking /etc/hosts file, so I don't need a permanent root. This sounds like just the sort of exploit to do the trick, but I haven't looked at the technical details. I just want to do this before the next security update patches it.
Hmm .. something just doesn't sound right here.
True. The thing that doesn't sound right is the belief that security is binary. Security is a continuum and sometimes a series of tradeoffs. It's not, never has been, and never will be 100%.
So no, finding a security bug in the linux kernel doesn't mean that linux is any less secure. We know these things happen. The idea is that it happens LESS often, and with less severity, and with fewer downsides than with Windows.
Among the more serious exploits ive encountered, i must protest that "dirty cow" is not a sufficiently spooky enough name for this one. We all know Halloween approaches, so why not call it haunted cow? or zombie cow?
in addition, this exploit is far less severe than the shoulder surfing exploit of 2005 which resulted in direct root privilege access and a broken friendship, Margaret, that led me to conclude I could no longer trust you to use either the mini fridge or my Sriracha sauce anymore because friends dont just log in to anyones workstation Margaret, i trusted you and you deceived me.
Good people go to bed earlier.
For Linux, it's the most serious local privilege escalation ever.
For Windows, it's Friday.
I found one of these "exploits in the wild":
https://github.com/dirtycow/dirtycow.github.io/blob/master/dirtyc0w.c
It works on the three Linux machines I first tested it on. /etc/secretfile.txt abcde
$ dirtyc0w
simply (over)writes abcde to the beginning of the file.
Fix seems to be available for none of the systems right now.
At least it requires a local account.... I mean, after all, it must be considered a security problem to allow web users to upload binaries or run arbitrary commands via a web server anyway. But if I was responsible for a students lab with hundreds of Linux computers I would be a little nervous.