Tag Archives: VirtualBox

Potential RCE in Nessus 7 and attacks on Vulnerability Scanners

A few days ago I saw an interesting youtube video (UPD. 14.05.18 Not available anymore) in my Facebook feed. It is demonstrating the exploitation of the RCE vulnerability in Tenable Nessus Professional 7.0.3. Currently we have very few information about this vulnerability: only youtube video, which is mentioned only on ExploitWareLabs facebook page.

Nessus 7.0.3 RCE

While there is no exploit in public access, it’s hard to say how it actually works. It’s also not clear what versions of Nessus are affected. 7.0.3 is the latest version currently. Because of API disabling in Nessus 7 many users are still on 6.11.3. It is not clear whether they are affected or not.

This even can be a fake video. Therefore, I specifically write “potential RCE”. I will update this post when more data is available.

UPD. 14.05.18 In the comments to my Facebook post anonymous account Destring Portal posted a comment with the second video of Nessus RCE exploitation and it seems, that it was made by the same author. In this video, the author runs a remote shell on the Nessus host and executes various commands. I will add review of this second video bellow.

Nessus RCE second video

UPD. 10.05.18 Renaud Deraison, Co-Founder and CTO of Tenable, commented on my post at Linkedin:

Our research team studied the video and we have several reasons to doubt its authenticity. We’ve conducted a thorough audit over the last 48 hours based the few details that are in the video and didn’t find anything. We reached out the researcher and instead of replying he removed the video*. We’ll communicate if indeed there is a risk.

In general, you are right though – the security of scanners is of paramount importance. This actually is a topic I’ve been extremely worried about ever since the early days of Nessus. We have a number of security mechanisms in place (interpreted language for the detection scripts, ciphered temporary files, very limited runtime environment) which really aim to limit the risk of being exploited but also to mitigate the risk should the scanner be compromised. I actually did a few talks in the past about scanning “rogue hosts” and we continue to treat all input as hostile.

Again, we’re continuing to investigate the matter and will let you know if we find anything.

* currently video is still available on the same address; it could be probably blocked for some time. (UPD. 14.05.18 Not available anymore)

In any case, it’s a good reason to talk about vulnerabilities of such kind, how they appear and how to protect Vulnerability Scanners from attackers.

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VirtualBox GuestAdditions for Linux Guest OS

I often work with VirtualBox virtual machines and need to install GuestAdditions to use GUI applications comfortably. So, I decided to collect here some configuration scripts.

VirtualBox GuestAdditions

CentOS 7

In the configuration a new VirtualBox machine I add 2 network adapters:

  • Host Only Network
  • NAT

Installing clean CentOS (CentOS-7-x86_64-DVD-1611)

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Scaner-VS: Vulnerability Management solution for Russian Military

Scaner-VS is a Vulnerability Assessment system developed by Moscow-based NPO Echelon. It’s pretty popular in Russian government organizations, especially in Russian Army, because it comply all government requirements, has all necessary certificates and is relatively cheap.

Scaner-VS webgui

As for requirements and certificates, NPO Echelon itself is an important certification authority, so they know how to do the things right. It’s not a secret product or something. You can request trial version freely at http://scaner-vs.ru/version-for-testing/. But note, that it is only available in Russian. I am also sorry, but screenshots in this post will be also in Russian. I will try to do my best to describe them properly.

When you fill the form on Echelon website, you will soon get a link to 3.3 gb .iso file by email. Run it in VirtualBox virtual machine (choose Debian 64 or Debian 32).

Here is a boot menu. Choose first default option.

Scaner-VS boot

Some seconds later you will see Linux desktop environment with Scaner-VS web-GUI opened in Firefox.

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GSM Community Edition and lagging OpenVAS Plugin Feed

As I already wrote in “Installing OpenVAS 9 from the sources“, since May 2017 OpenVAS 9 is available in a form of free virtual appliance. It is called GSM Community Edition (GCE) and is based on Greenbone commercial product GSM ONE.

What’s the difference between GSM ONE and free GCE? GSM Community Edition uses different Community Feed of NASL plugins, it can’t be updated automatically and does not have some management features. The most important, in my opinion, is that it does not support OpenVAS Management Protocol (OMP), API for managing scanners. Only HTTPS for WebGUI and SSH are available.

GSM start screen

Talking about different NASL plugin feeds, I need to mention recent message by Jan-Oliver Wagner in Openvas-announce list.

That seems like Greenbone is rather tired of developing OpenVAS by themselves and watching how other companies use theirs engine and feeds, positioning themselves as an “alternative to Greenbone’s product at a better price”. So, they decided:

  1. “OpenVAS NVT Feed” will be renamed to “Greenbone Community Feed”
  2. Public access to the “openvas-nvts” SVN repository will be forbidden, but the license of nasl plugins won’t be changed.
  3. Now Community Feed lags 14 days from commercial feed, but Greenbone would like to make an actual feed, but without some features for enterprise customers.

I really care about Greenbone and they, of course, do as they think is better for the company and OpenVAS community, but at the same time it reminds me situation with Tenable and Nessus. Maybe not so radical. But definitely in the same direction.

Feed delayed for 2 week can’t be used effectively for obvious reasons. If you see exploitation of critical vulnerability like WannaCry in the wild and will need to wait 2 weeks to check your infrastructure, it’s a nonsense! 🙂 That’s mean that you just can’t rely on OpenVAS anymore. And if you use it, you should think about migration on commercial solution, for example on Greenbone’s GSM, or think about getting actual plugin feed somewhere else.

The good thing, it might show customers once again that knowledge base of Vulnerability Management solution is important and stimulate other security content developers to make own nasl scripts and feeds.

But let’s go back to GSM Community Edition. Detailed description of installation process you can find on official site. I will just describe my own experience.

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Installing OpenVAS 9 from the sources

In last month Greenbone Networks and OpenVAS development team have finally presented new OpenVAS 9 with new GUI, improved multi-scanner support, improved asset management, etc. We have been waiting for this release for 2 years!

Upd. Please note, that entire procedure for separating scanners onto separate hardware/distributed hardware in different datacenters has changed completely – and that it’s a good idea to get familiar with this new procedure prior to upgrading to OpenVAS 9. 😉

For installing OpenVAS 9 from the sources I used the same script as for OpenVAS 8 installation last year. More details about this script and why you may need it you can read in the post “openvas_commander for OpenVAS installation and management“.

OpenVAS 9 Dashboards

I fixed the script a bit because of these changes in OpenVAS9:

  • openvas-nvt-syncwas renamed to greenbone-nvt-sync
  • openvas-mkcert and openvas-mkcert-client were replaced by openvas-manage-certs

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