“Dirty COW”, the most dangerous Linux Bug for the last 9 years

For the Past 9 Years, Linux Kernel has been Plagued with Dirty Cow – A Privilege-Escalation Bug

Red Hat, the leading open source software development firm, has revealed that Linux Kernel has been infected with a serious bug for the past 9 years. The bug has been dubbed as Dirty Cow. It is deemed dangerous because, through this bug, an attacker can get write access to read-only memory.

According to Red Hat’s research, the bug was identified in the method adopted by Linux Kernel’s memory subsystem to handle “the copy on write (COW) breakage of private read-only memory mapping.”

With this ability, the attacker can easily exploit the system by gaining Write Access to read-only memory.

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Talking to Ars Technica, Senior Security Researcher at Azimuth Security, Dan Rosenberg states that this particular bug is so far the most serious of all bugs ever found in Linux systems. The fact that this bug has been there for the last 9 years makes the situation even more concerning.

“It’s probably the most serious Linux local privilege escalation ever. 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,” said Rosenberg.

It was also explained that Dirty Cow can be exploited against Web Hosting service providers that offer shell access allowing one visitor to attack others. The attacker can even acquire root access if an SQL injection weakness is combined with Dirty Cow. SQL injection weakness if found in a website can allow untrusted users to execute malicious codes.

Dirty Cow is also dubbed as privilege-escalation or privilege elevation vulnerability. Such vulnerabilities let attackers gain maximum access to any targeted computer and get greater control over their activities. The bug comes from the race condition variety.

Phil Oester, a Linux developer, maintains that “The vulnerability is easiest exploited with local access to a system such as shell accounts.”

The revelation arrived amidst claims from Kees Cook, a researcher at Google, who stated that any Linux bug has an average lifetime of 5 years.

Red Hat classified this bug as having high severity and was categorized as CVE-2016-5195. Linux has already released the patch for this bug and the company has requested all the users to install it immediately.

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