Tag Archives: Drive-by-Download Attack

Chrome’s new Site Isolation feature protects users from the Spectre vulnerability

14 July 2018



A new variant Spectre V1.1 (1) was published on July, 10 2018 by Vladimir Kiriansky and Carl Waldspurger. The vulnerability is tracked in CVE-2018-3693 (2). The good news is that the CVSS V3 score is 5.6 (Medium) with attack vector Local.

As with the original Spectre vulnerability CVE-2017-5753 (3) published in January 2018 the greatest risk for business users and consumers bears in malicious websites weaponized with drive-by downloads or viruses (4) using the Spectre POC code.

The virus issue is easy to mitigate. The inbuilt auto-update feature of anti-malware solutions ensures that the latest pattern updates are available within few hours after a virus shows up in the wild.

But the internet issue is much harder to solve, in particular for consumers and SME. Fortunately, Goggle announced on July 11, 2018 a new feature Site Isolation for the Chrome browser that mitigates the risk borne from the Spectre vulnerability.

Chrome is based on a multi-process architecture. Different tabs are rendered by different renderer processes. With site isolation enabled, cross-site iframes are rendered in different processes than the parent frame and data exchange between the parent and the iframe processes is blocked. For a technical overview see Charlie Reis’s post ‘Mitigating Spectre with Site Isolation in Chrome’ (5). Further details are available from the Chromium Projects (6).

Site Isolation is available since Chrome 67. Input chrome://flags/#enable-site-per-process to check if the feature is enabled:

Chromium Strict Site Isolation Feature

Chromium Strict Site Isolation Feature

If you use an older version of Chrome Site Isolation is the best opportunity to update to the latest version.

Have a great weekend.

  1. Beltov M. CVE-2018-3693: New Spectre 1.1 Vulnerability Emerges [Internet]. SensorsTechForum. 2018 [cited 2018 Jul 14]. Available from: https://sensorstechforum.com/cve-2018-3693-new-spectre-1-1-vulnerability-emerges/
  2. CVE-2018-3693 Detail [Internet]. NIST NVD. 2018 [cited 2018 Jul 14]. Available from: https://nvd.nist.gov/vuln/detail/CVE-2018-3693
  3. CVE-2017-5753 Detail [Internet]. NIST NVD. 2018 [cited 2018 Jul 14]. Available from: https://nvd.nist.gov/vuln/detail/CVE-2017-5753
  4. FortiGuard SE Team. Meltdown/Spectre Update [Internet]. Fortinet Blog. 2018 [cited 2018 Jul 14]. Available from: https://www.fortinet.com/blog/threat-research/the-exponential-growth-of-detected-malware-targeted-at-meltdown-and-spectre.html
  5. Reis C. Mitigating Spectre with Site Isolation in Chrome [Internet]. Google Online Security Blog. 2018 [cited 2018 Jul 14]. Available from: https://security.googleblog.com/2018/07/mitigating-spectre-with-site-isolation.html
  6. The Chromium Projects. Site Isolation – The Chromium Projects [Internet]. [cited 2018 Jul 14]. Available from: https://www.chromium.org/Home/chromium-security/site-isolation

AppGuard is an important part of a comprehensive security stack

16 July 2016

In the past weeks I tried hard to get an idea of the capabilities of Blue Ridge Networks AppGuard. To be honest, I would not like to miss AppGuard anymore. AppGuard creates the really good feeling that, under certain conditions, many cyber-attacks are simply rendered ineffective.

AppGuard is a perfect means against all kind of Trojans and downloaders, in particular zero days. Characteristic for this kind of malware is that the malware directly drops a malicious program or downloads a malicious program from the attacker’s server and executes it afterwards. This includes e.g. most of the known Ransomware.

The User Space and MemoryGuard concept just blocks this kind of malware out-of-the-box, provided that the User Space concept is not undermined by a user who is working with high privileges permanently. In fact, if the user works with privileges which allow the Trojan program to store files outside the User Space, the concept will no longer work.

It is strongly recommended to work with the least possible privileges under normal conditions. For the case higher privileges are requested, set up an extra account with the required privileges and supply the credentials of this account if UAC requests higher privileges.

More advanced malware may try to use the Windows auto-elevation feature to acquire higher privileges and to compromise AppGuard. To protect from auto-elevation attacks just set UAC to ‘Always notify me’.

This works even in the case of a gaming computer, where e.g. WOW and TeamSpeak are heavily used. Why shouldn’t it work on a standard system?

In addition, it is strongly recommended to disable macro execution in all kind of office software, e.g. Microsoft Office, OpenOffice or LibreOffice.

Memory Guard protects against all kind of zero-day drive-by downloads, PuP (Potentially unwanted Programs) or file-less malware.

My comprehensive security stack

My comprehensive security stack. Click to enlarge.


AppGuard does not protect against any kind of password phishing attacks. Although popular internet browsers block many malicious URLs through URL reputation, e.g. SmartScreen Filtering in Internet Explorer or Firefox, this will not protect in the case of zero-days.

To reduce the likelihood of credential theft, turn on Two-Factor Authentication (TFA) for as many as possible internet services you use. If TFA cannot be enabled, choose a strong password and take care, means:

User awareness is the basic part of the entire security stack!

To put it succinctly: The proposed security stack will dramatically reduce the risk of cyber-attacks. Blue Ridge Networks AppGuard is an important component of this stack, in particular for the protection against all kind of zero-days.

Have a good weekend.

Attention! Attention! Ransomware Cerber talks to you

16 April 2016

I use Adobe Flash Player only if there’s no other way. The plugin is deactivated by default, and activated only in the case I view an SC Magazine seminar.

Nevertheless, the latest security flaws, in particular CVE-2016-1019, must be patched as soon as possible. Because this bug was being exploited in drive-by download attacks that infect computers with ransomware Cerber after visiting tainted websites.

New on Cerber is that it has a computer-generated voice. And, that the malware is delivered by a drive-by download. With this, the first line of defense, your users, is of limited effectiveness because they are unable to determine that they were tricked.

From my point of view, a next generation endpoint protection tool, that containerizes all applications which connect to the Internet, is the means of choice in the defense of drive-by attacks. Since I am a strong advocate of the Zero-Trust Network concept, I recommend to containerize applications even if they access internal network resources only.

In addition, containerization frees us from the patching treadmill, at least to some extent, since we are no longer forced to install every patch on thousands of computers.

Unfortunately, Microsoft missed the opportunity to run Flash Player more secure in Windows 10.

Process Explorer View of Edge and FLashPlayer

Process Explorer View of Edge and Flash Player. Click to enlarge.

Edge runs by default at integrity level AppContainer. This makes sure that access to system resources is widely blocked. By contrast, Flash Player has access to lots of system resources because it runs at Medium Integrity Level.

Have a good weekend, and patch your Flash Player!

How to mitigate Drive-by-Downloads Attacks

24 January 2014

Bad news for Adobe Flash Player users. A new critical vulnerability (CVE-2015-0311) was found in Adobe Flash Player… Successful exploitation could cause a crash and potentially allow an attacker to take control of the affected system.

In the Adobe Security Bulletin we read ‘We are aware of reports that this vulnerability is being actively exploited in the wild via drive-by-download attacks against systems running Internet Explorer and Firefox on Windows 8 and below.’

Drive-by-download (DbD) attacks are a often used technology to exploit vulnerabilities in programs. In his post ‘How malware works: Anatomy of a drive-by download web attack’ John Zorabedian from SOPHOS gives a detailed description about how DbD attacks work.

The shocking fact is: It’s not even necessary to click a link on the malicious site. If you just load the site the malware download could start, automatically and silently in the background.

The good news is that we could almost completely deactivate this feature, namely without considerable comfort loss. The Security Technical Implementation Guide (STIG) for Internet Explorer 11 shows the direction.

STIG’s are primarily used to secure the information systems of the Departments of Defense, but this should not deter us from using STIGs to secure our systems at home, and of course in our businesses.

STIGs are available from http://www.stigviewer.com/stigs for operating systems, web servers, databases or applications. They are an excellent means to secure the devices that are connected to the internet against malicious attacks. But, be aware that 100% safety could not be achieved.

Applying STIGs to Microsoft operating systems and applications is very easy if you are familiar with the registry editor regedit.exe and the local group policy editor gpedit.msc. Since only standard windows security options are used the recommended settings could be applied to all computers.

Back to the Drive-by-Download attacks. To prevent DbD attacks we have to configure Internet Explorer such that downloads not consented by the user are blocked. Sound’s easy, doesn’t it? We have just to work through the STIG for Internet Explorer 11 and implement the relevant fixes:

Step 1: Block non user-initiated file downloads

The DoD requirements block unconsented downloads from the Restricted Sites Zone and the Internet Zone. Since I would not trust computers in local networks as well I would strongly recommend to block unconsented downloads from all zones.

Implement at least Fixes from Finding Ids V-46705 and V-46643

Step 2: Block non user-initiated file downloads for Internet Explorer Processes

Implement Fixes from Finding IDs V-46779 and V-46781

Step 3: Enforce Protected Mode

Protected Mode protects Internet Explorer from exploited vulnerabilities by reducing the locations Internet Explorer can write to in the registry and the file system. I would recommend to enforce protected mode for all zones.

Implement at least Fixes from Finding IDs V-46685 and V-46681

Step 4: Enforce Enhanced Protected Mode on 64 bit Windows Systems

Implement Fix from Finding ID V-46987

That’s it for today. Please keep in mind that 100% safety could not be achieved, even if you implement the 155 fixes from the IE11 STIG.

Don’t Panic! And have a good weekend.