what is Dirty Cow

1- What is Ethical  Hacking ?
  

 Ethical hacking and ethical hacker are terms used to        describe hacking performed by a company or individual to help identify potential threats on a computer or network. An ethical hacker attempts to bypass system security and search for any weak points that could be exploited by malicious hackers. This information is then used by the organization to improve the system security, in an effort to minimize or eliminate any potential attacks.

2- What is Dirty Cow in Linux ?
Experts disclosed a new Linux kernel vulnerability dubbed Dirty COW that could be exploited by an unprivileged local attacker to escalate privileges.

The security expert Phil Oester discovered in the Linux kernel a new flaw, dubbed ‘Dirty COW‘ that could be exploited by a local attacker to escalate privileges.

The name “Dirty COW” is due to the fact that it’s triggered by a race condition in the way the Linux kernel’s memory subsystem handles copy-on-write (COW) breakage of private read-only memory mappings.

According to the security advisory published by Red Had, the vulnerability, tracked as CVE-2016-5195, allows local attackers to modify existing setuid files.

“A race condition was found in the way the Linux kernel’s memory subsystem handled the copy-on-write (COW) breakage of private read-only memory mappings. An unprivileged local user could use this flaw to gain write access to otherwise read-only memory mappings and thus increase their privileges on the system.” states the Red Had security advisory.

“This could be abused by an attacker to modify existing setuid files with instructions to elevate privileges. An  exploit using this technique has been found in the wild.”