Category Archives: Vulnerability Management

Adding custom NASL plugins to Tenable Nessus

Making custom NASL scripts (plugins) for Nessus is a pretty complicated process. Basically, NASL (Nessus Attack Scripting Language) is an internal instrument of Tenable and it seem that they are not really interested in sharing it with the community. The only publicly available official documentation, NASL Reference Guide and NASL2 reference manual, was written at least 13 years ago. Certainly many things changed since then in the actual product.

Adding custom NASL plugins to Tenable Nessus

However, it’s still possible to add custom NASL scripts into the plugin set of your Nessus server. Let’s see how to do it. Everything was tested in the latest Nessus 8.

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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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ISACA Moscow Vulnerability Management Meetup 2018

Last Thursday, September 20th, I spoke at ISACA Moscow “Vulnerability Management” Meetup held at Polytechnic University. The only event in Moscow devoted solely to Vulnerability Management. So I just had to take part in it. 🙂

ISACA VM 2018 Alexander Leonov

The target audience of the event – people who implement the vulnerability management process in organizations and the employees of Vulnerability Management vendors. I noticed groups of people from Altex-Soft (Altx-Soft), Positive Technologies and Vulners.

It was very interesting to see such concentration of Vulnerability and Compliance Management specialists in one place. Questions from the audience were relevant and often concerned the weaknesses of competitors. 😉 Here I will make a brief overview of the reports. You can also read here about previous year event at “ISACA Moscow Vulnerability Management Meetup 2017“.

Talking about the audience, there were fewer people than last year, but still a lot:

ISACA VM 2018 auditorium small

The event was recorded. I will add video here as soon as it’s ready.

upd. Video in Russian. My presentation starts at 1:35:56

The event was conducted entirely in Russian, including all the slides. So, maybe I will make English subtitles and voiceover, at least for my part.

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Psychological Aspects of Vulnerability Remediation

In my opinion, Remediation is the most difficult part of Vulnerability Management process. If you know the assets in your organization and can assess them, you will sooner or later produce a good enough flow of critical vulnerabilities. But what the point, if the IT team will not fix them?

Kübler-Ross model and Tsunami of Vulnerability Tasks

Kübler-Ross model and Tsunami of Vulnerability Remediation Tasks

Just think about it. The only thing that your colleagues from  IT team see is an unexpected  tsunami of the patching tasks. They most likely don’t understand WHY they should do it. They most likely don’t know about the concepts of Attack Surface minimization and Attack Cost maximization. From their point of view it’s just some stupid requirements from InfoSec team imposed with only one goal – to make their life miserable.

So, they may think that denial and pushing back can solve all their problems. And, frankly, this may work. There are countless ways to sabotage Vulnerability Remediation. Most main and common are the following:

  • I don’t understand how to patch this.
  • I already patched this, there should be a false positive in the scanner.
  • Why should we patch this? The vulnerability is not exploitable. Or it is exploitable in theory, but not exploitable in our particular infrastructure. Or this server is not critical and, even if it will be compromised, there won’t be a huge impact. So, we will not patch it.

In each individual case Vulnerability Analyst can describe and proof his point, but doing this for each vulnerability will require insane amount of time and efforts and will paralyze the work. It is basically the Italian strike or work-to-rule.

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Making Expect scripts for SSH Authentication and Privilege Elevation

Expect can help you to automate interactive console applications. For example, expect script can go to some Linux host via SSH with password authentication, make additional authentication procedures (su, sudo) to elevate privileges and execute some commands. Like Vulnerability and Compliance management products do during the active Linux scanning, right? 🙂 For example you can get the list of installed packages and make Vulnerability Assessment without Vulnerability Scanner.

Expect SSH exec

Actually, the tool is pretty old. It was presented more than 20 years ago! And perhaps now it makes more sense to use python scripts, for example paramiko with paramiko-expect. Or even use some software provisioning tool, like Ansible. But my fun was in creating (generating?) a small old-school scripts that could be sent to any remote host (with expect installed) to gather information from the accessible hosts.

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CyberThursday: Asset Inventory, IT-transformation in Cisco, Pentest vs. RedTeam

Two weeks ago I was speaking at a very interesting information security event – CyberThursday. This is a meeting of a closed Information Security practitioners group. The group is about 70 people, mainly from the financial organizations, telecoms and security vendors.

CyberThursday 2018 Asset Inventory

These meetings have a rather unique atmosphere. Almost everyone knows each other. The event has no permanent place. It constantly moves between the offices of large Russian companies. The hoster, usually a CISO, can bring his IT and InfoSec colleagues. For others, only “bring a friend” format is available. This helps keep the event focussed and very informal. Participants propose and approve the topics by voting in the chat group. There is no place for marketing, all topics are practical and relevant.

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Asset Inventory for Internal Network: problems with Active Scanning and advantages of Splunk

In the previous post, I was writing about Asset Inventory and Vulnerability Scanning on the Network Perimeter. Now it’s time to write about the Internal Network.

Typical IT-infrastructure of a large organization

I see a typical IT-infrastructure of a large organization as monstrous favela, like Kowloon Walled City in Hong Kong. At the beginning it was probably wisely designed, but for years it  was highly effected by spontaneous development processes in various projects as well as multiple acquisitions. And now very few people in the organization really understand how it all works and who owns each peace.

There is a common belief that we can use Active Network Scanning for Asset Inventory in the organization. Currently, I’m not a big fan of this approach, and I will try to explain here the disadvantages of this method and mention some alternatives.

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