Tag Archives: Redhat

Scanvus – my open source Vulnerability Scanner for Linux hosts and Docker images

Hello everyone! This video was recorded for the VMconf 22 Vulnerability Management conference, vmconf.pw. I will be talking about my open source project Scanvus. This project is already a year old and I use it almost every day.

Alternative video link (for Russia): https://vk.com/video-149273431_456239100

Scanvus (Simple Credentialed Authenticated Network VUlnerability Scanner) is a vulnerability scanner for Linux. Currently for Ubuntu, Debian, CentOS, RedHat, Oracle Linux and Alpine distributions. But in general for any Linux distribution supported by the Vulners Linux API. The purpose of this utility is to get a list of packages and Linux distribution version from some source, make a request to an external vulnerabililty detection API (only Vulners Linux API is currently supported), and show the vulnerability report.

Scanvus can show vulnerabilities for

  • localhost
  • remote host via SSH
  • docker image
  • inventory file of a certain format

This utility greatly simplifies Linux infrastructure auditing. And besides, this is a project in which I can try to implement my ideas on vulnerability detection.

Example of output

For all targets the output is the same. It contains information about the target and the type of check. Then information about the OS version and the number of Linux packages. And finally, the actual information about vulnerabilities: how many vulnerabilities were found and the criticality levels of these vulnerabilities. The table shows the criticality level, bulletin ID, CVE list for the bulletin, and a comparison of the invulnerable fixed package version with the actual installed version.

This report is not the only way to present results. You can optionally export the results to JSON (OS inventory data, raw vulnerability data from Vulners Linux API or processed vulnerability data).

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End of CentOS Linux. Where to migrate?

Hello everyone! As you probably know, CentOS Linux, the main Enterprise-level Linux server distribution, will soon disappear. It wasn’t hard to predict when RedHat acquired CentOS in 2014, and now it is actually happening. End of life of CentOS Linux 8 was 31.12.2021. There won’t be CentOS Linux as downstream for RedHat anymore. Only CentOS Stream, that will be upstream for RedHat, more or less a testing distro like Fedora.

Of course, it is a matter of debate whether security guys can actually decide which Linux distributions a company will use and set that as a requirement. But in any case, the security guys will definitely take part in the decision. I made a poll in my Telegram channel. 113 people voted. So, let’s take a look at the results and discuss which of the Linux distributions we can recommend to IT teams.

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Vulners Linux Audit API for Host Vulnerability Detection: Manual Auditing, Python Scripting and Licensing

Hello everyone! This episode will be about Vulners Linux Audit API, which allows you to detect vulnerabilities on a Linux host knowing only the OS version and installed packages. I had a similar post about this 4 years ago, but some details have changed, so I came back to this topic.

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What’s new in Nessus 8

Today Tenable released a new version of their famous vulnerability scanner – Nessus 8. The existing scanner nodes don’t see the updates yet, but the installation binaries are already available. So you may try to install it.

What's new in Tenable Nessus 8

This major release will be way more positive than the previous one. Of course Tenable did NOT return the multi-user mode and API in Nessus Professional. But on the other hand, they did NOT cut the functionality even further. They even added new features in GUI. And, what is the most important, they did NOT switch to the assets-based licensing (at least yet). 🙂

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Vulnerability Databases: Classification and Registry

What publicly available Vulnerability Databases do we have? Well, I can only say that there are a lot of them and they are pretty different. Here I make an attempt to classify them.

It’s quite an ungrateful task. No matter how hard you try, the final result will be rather inaccurate and incomplete. I am sure someone will be complaining. But this is how I see it. 😉 If you want to add or change something feel free to make a comment bellow or email me@avleonov.com.

The main classifier, which I came up with:

  • There are individual vulnerability databases in which one identifier means one vulnerability. They try to cover all existing vulnerabilities.
  • And others are security bulletins. They cover vulnerabilities in a particular product or products. And they usually based on on patches. One patch may cover multiple vulnerabilities.

I made this diagram with some Vulnerability Databases. Note that I wanted to stay focused, so there are no exploit DBs, CERTs, lists of vulnerabilities detected by some researchers (CISCO Talos, PT Research, etc.), Media and Bug Bounty sites.

Vulnerability Databases classification

For these databases the descriptions of vulnerabilities are publicly available on the site (in html interface or downloadable data feed), or exist in a form of paid Vulnerability Intelligence service (for example, Flexera).

On one side there are databases of individual vulnerabilities, the most important is National Vulnerability Database. There are also Chinese, Japanese bases that can be derived from NVD or not.

On the other side we have security bulletins, for example RedHat Security Advisories.

And in the middle we have a Vulnerability Databases, for which it is not critical whether they have duplicated vulnerability IDs or not.

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Divination with Vulnerability Database

Today I would like to write about a popular type of “security research” that really drives me crazy: when author takes public Vulnerability Base and, by analyzing it, makes different conclusions about software products or operating systems.

CVE Numbers their occult power and mystic virtues

The latest research of such type, was recently published in CNews – a popular Russian Internet portal about IT technologies. It is titled ““The brutal reality” of Information Security market: security software leads in the number of holes“.

The article is based on Flexera/Secunia whitepaper. The main idea is that various security software products are insecure, because of amount of vulnerability IDs related to this software existing in Flexera Vulnerability Database. In fact, the whole article is just a listing of such “unsafe” products and vendors (IBM Security, AlienVault USM and OSSIM, Palo Alto, McAfee, Juniper, etc.) and the expert commentary: cybercriminals may use vulnerabilities in security products and avoid blocking their IP-address; customers should focus on the security of their proprietary code first of all, and then include security products in the protection scheme.

What can I say about these opuses of this kind?

They provide “good” practices for software vendors:

  • Hide information about vulnerabilities in your products
  • Don’t release any security bulletins
  • Don’t request CVE-numbers from MITRE for known vulnerabilities in your products

And then analysts and journalists won’t write that your product is “a leader in the number of security holes”. Profit! 😉

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Vulnerability Assessment without Vulnerability Scanner

This will be a practical confirmation of my thesis from “Vulnerability scanners: a view from the vendor and end user side“: the scanner for one operating system is easy to make. I also want to demonstrate that data collection and data analysis for Vulnerability Assessment may be successfully performed separately. There is no need to take the data directly from the vulnerable hosts, when it is already stored somewhere else, for example in IT monitoring systems.

Assessment without vulnerability scanner

The opacity of data collection and the need to have a privileged account on the remote host, traditionally causes conflicts between IS and IT departments and complicates implementation of VM process.

So, to detect vulnerabilities on our Linux host we need to know what version of the packages contain vulnerabilities, which versions of packages are installed on our hosts, and learn how to compare versions.

How do I know which versions of packages are vulnerable?

Vulnerable versions of packages are listed in official security bulletins:
RHEL – https://access.redhat.com/errata/RHSA-2016:0304
CentOS – https://lists.centos.org/pipermail/centos-announce/2015-April/021064.html
Debian – http://www.debian.org/security/2015/dsa-3197
Ubuntu – http://www.ubuntu.com/usn/usn-2537-1/

CESA bulletin example

Of course, you will need to parse them first. Or you can just download the same content already parsed and presented in JSON format with Vulners.
download CESA bulletins from Vulners
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