Hack The Sec-Leading Resource Of Linux Tutorial: Linux Security

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<u><span style="color: #990000;">Install RkHunter for Rootkit/Trojan Scanning</span></u></h2>
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<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">rkhunter (Rootkit Hunter) is a Unix-based tool that scans for rootkits, backdoors and possible local exploits. It does this by comparing SHA-1 hashes of important files with known good ones in online databases, searching for default directories (of rootkits), wrong permissions, hidden files, suspicious strings in kernel modules, and special tests for Linux and FreeBSD.</span></span></div>
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<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">The tool has been written in Bourne shell, to allow for portability. It can run on almost all UNIX-derived systems.</span></span></div>
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<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-family: Courier New, Courier, monospace;"><span style="font-size: 12px; line-height: 15.6px;">$ wget http://space.dl.sourceforge.net/project/rkhunter/rkhunter/1.3.8/rkhunter-1.3.8.tar.gz
$ cd rkhunter-1.3.8
$ sh installer.sh</span></span></pre>
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<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">To see the list of commands which can be executed use: the command below:</span></span></div>
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<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-family: Courier New, Courier, monospace;"><span style="font-size: 12px; line-height: 15.6px;">$ rkhunter –help</span></span></pre>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-family: Courier New, Courier, monospace;"><span style="font-size: 12px; line-height: 15.6px;"><a href="http://www.hackthesec.co.in/">www.hackthesec.co.in</a></span></span></pre>
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How to Install RkHunter for Rootkit/Trojan Scanning

Install RkHunter for Rootkit/Trojan Scanning rkhunter (Rootkit Hunter) is a Unix-based tool that scans for rootkits, backdoors and poss...

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<span style="color: #0b5394; font-family: Verdana, sans-serif; font-size: large;"><b>Zero-Day Flaw Found in 'Linux Kernel' leaves Millions Vulnerable</b></span><br />
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A new critical zero-day vulnerability has been discovered in the<b style="border: 0px; font-family: inherit; font-size: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"> Linux kernel </b>that could allow attackers to gain root level privileges by running a malicious Android or Linux application on an affected device.</div>
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<br style="content: ' '; display: block; margin: 20px 0px 0px; outline: 0px; padding: 0px;" />The critical Linux kernel flaw (<a href="http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=2016-0728" rel="nofollow" style="border: 0px; color: #1177b8; font-family: inherit; font-size: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; margin: 0px; outline: none; padding: 0px; text-decoration: none; vertical-align: baseline;" target="_blank">CVE-2016-0728</a>) has been identified by a group of researchers at a startup named Perception Point.</div>
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The vulnerability was present in the code since 2012, and affects any operating system with <b style="border: 0px; font-family: inherit; font-size: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Linux kernel 3.8 and higher</b>, so there are probably tens of millions of computers, both 32-bit and 64-bit, exposed to this flaw.</div>
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However, the most bothersome part is that the problem affects <b style="border: 0px; font-family: inherit; font-size: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Android versions KitKat and higher</b>, which means about 66 percent of all Android devices are also exposed to the serious Linux kernel flaw.</div>
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Impact of the Zero-Day Vulnerability</h3>
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An attacker would only require local access to exploit the flaw on a Linux server.</div>
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If successfully exploited, the vulnerability can allow attackers to get root access to the operating system, enabling them to delete files, view private information, and install malicious apps.</div>
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Usually, flaws in Linux kernel are patched as soon as they are found; therefore, Linux-based operating systems are considered to be more secure than others. However, zero-day vulnerability recently discovered in the Linux kernel made its way for almost 3 years.</div>
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The Cause of the Critical Linux Kernel Vulnerability</h3>
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The vulnerability is actually the result of a <b style="border: 0px; font-family: inherit; font-size: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Reference Leak</b> in the keyrings facility built into various flavors of Linux. The keyrings facility is primarily a way to encrypt and store login data, encryption keys and certificates, and then make them available to applications.</div>
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However, a reference leak could be abused by attackers to ultimately execute arbitrary code in the Linux kernel.</div>
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So far, the researchers said, no exploits have been discovered in the wild that take advantage of this vulnerability.</div>
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Perception Point has provided a technical analysis of the vulnerability and how one can exploit it, including <a href="https://gist.github.com/PerceptionPointTeam/18b1e86d1c0f8531ff8f" rel="nofollow" style="border: 0px; color: #1177b8; font-family: inherit; font-size: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; margin: 0px; outline: none; padding: 0px; text-decoration: none; vertical-align: baseline;" target="_blank">proof-of-concept</a> (PoC) exploit code published on its Github page.</div>
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Patch Expected to Roll Out Soon</h3>
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The good news is that Perception Point has already reported the flaw to the Linux team, and patches are expected to roll out today to devices with automatic updates.</div>
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However, it may take a little longer on Android devices to receive the patch, given the fact that most updates aren’t pushed automatically by manufacturers and carriers.<br style="content: ' '; display: block; margin: 20px 0px 0px; outline: 0px; padding: 0px;" /><br style="content: ' '; display: block; margin: 20px 0px 0px; outline: 0px; padding: 0px;" /><h3 style="border: 0px; font-family: inherit; font-size: 1.4em; font-stretch: inherit; font-style: inherit; font-variant: inherit; line-height: 35px; margin: 0px; outline: 0px; padding: 0px; text-align: left !important; vertical-align: baseline;">
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Type following commands as per your Linux distro:</div>
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<li style="border: 0px; font-family: inherit; font-size: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;"><b style="border: 0px; font-family: inherit; font-size: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">Debian or Ubuntu Linux:</b> sudo apt-get update && sudo apt-get upgrade</li>
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