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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."
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.