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<h1 class="m-title">[TZO-19-2020] - AVIRA Generic AV Bypass (ISO Container) - CVE-2020-9320</h1>
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<em>From</em>: Thierry Zoller <thierry () zoller lu>
<em>Date</em>: Fri, 21 Feb 2020 09:31:09 +0100
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<pre style="margin: 0em;">________________________________________________________________________
From the low-hanging-fruit-department
AVIRA Generic Malformed Container bypass (ISO Container)
________________________________________________________________________
Release mode : Coordinated disclosure / Vendor does not disclose
CVE : CVE-2020-9320
Ref : [TZO-19-2020] - AVIRA Generic AV Bypass (ISO Container)
Vendor : AVIRA
Status : PATCHED - Engine version 8.3.54.138.
CVE : none provided,
</pre><tt>Blog :
</tt><tt><a rel="nofollow" href="https://blog.zoller.lu/p/from-low-hanging-fruit-department-avira.html">https://blog.zoller.lu/p/from-low-hanging-fruit-department-avira.html</a>
</tt><pre style="margin: 0em;">Vulnerability Dislosure Policy: <a rel="nofollow" href="https://caravelahq.com/b/policy/20949">https://caravelahq.com/b/policy/20949</a>
Affected Products
=================
AV Engine below 8.3.54.138
All Avira products :
- Avira Antivirus Server
- Avira Antivirus for Endpoint
- Avira Antivirus for Small Business
- Avira Exchange Security (Gateway)
- Avira Internet Security Suite for Windows
- Avira Prime
- Avira Free Security Suite for Windows
- Cross Platform Anti-malware SDK
Attention:
</pre><tt>Avira does not patch or update their very popular command line scanner
</tt><tt>that is still available for download on their website. Since Avira does
</tt><tt>not release and advisory their customers are none the wiser.
</tt><pre style="margin: 0em;">
</pre><tt>Avira licenses it's engine to many OEM Partners. The OEM Partners that
</tt><tt>use the Avira Engine may be vulnerable or not. I would advise that you
</tt><tt>reach out to the vendors listed below to know whether you are affected
</tt><tt>or not. OEM Partners
</tt><pre style="margin: 0em;">can reach out to me to retreive the POC in order to test.
AVIRA OEM Partners:
- F-Secure
- Sophos
- Barracude
- Alibaba Cloud Security
- Check Point
- CUJO AI
- TP-Link
- FujiSoft
- AWS
- Rohde and Schwarz
- Careerbuilder
- Huawei
- Dracoon
- Total Availability
- FixMeStick
- APPVISORY
- Tabidus
- Cyren
Source :
<a rel="nofollow" href="https://oem.avira.com/en/partnership/our-partners">https://oem.avira.com/en/partnership/our-partners</a>
I. Background
----------------------------
</pre><tt>Quote: "We protect people—like you—across all devices, both directly and
</tt><tt>via our OEM partnerships.We provide a wide variety of best-in-class
</tt><tt>solutions to enhance your protection, performance,
</tt><pre style="margin: 0em;">and online privacy—ranging from antivirus to VPN and cleanup technologies.
</pre><tt>A server security should get special attention, as a single employee
</tt><tt>might store a malicious file on the network and instantly cause a
</tt><tt>cascading damage across the entire organization.
</tt><tt>With Avira's solutions for server security you can prevent such
</tt><tt>scenarios by protecting your network, data, and web traffic. "
</tt><pre style="margin: 0em;">
Avira has the Trust Seal or the
<a rel="nofollow" href="http://www.teletrust.de/itsmig/">http://www.teletrust.de/itsmig/</a>
II. Description
----------------------------
</pre><tt>The parsing engine supports the ISO container format. The parsing engine
</tt><tt>can be bypassed by specifically manipulating the ISO Archive
</tt><tt>This leads to the Endpoint ignoring the container and the Gateways to
</tt><tt>let this file slip through uninspected.
</tt><pre style="margin: 0em;">
III. Impact
----------------------------
It bypasses Avira perimeter defenses and sheduled AV scans.
</pre><tt>Impacts depends on the contextual use of the product and engine within
</tt><tt>the organisation
</tt><tt>of a customer. Gateway Products (Email, HTTP Proxy etc) may allow the
</tt><tt>file through unscanned
</tt><tt>and give it a clean bill of health. Server side AV software will not be
</tt><tt>able to discover
</tt><tt>any code or sample contained within this ISO file and it will not raise
</tt><tt>suspicion even
</tt><tt>if you know exactly what you are looking for (Which is for example great
</tt><tt>to hide your implants
</tt><pre style="margin: 0em;">or Exfiltration/Pivot Server).
</pre><tt>There is a lot more to be said about this bug class, so rather than bore
</tt><tt>you with it in
</tt><pre style="margin: 0em;">this advisory I provide a link to my 2009 blog post
<a rel="nofollow" href="http://blog.zoller.lu/2009/04/case-for-av-bypassesevasions.html">http://blog.zoller.lu/2009/04/case-for-av-bypassesevasions.html</a>
IV. Patch / Advisory
----------------------------
PATCHED - Engine version 8.3.54.138.
V. Disclosure timeline
----------------------------
How Avira handled these reports in 2009 :
<a rel="nofollow" href="https://blog.zoller.lu/2009/04/avira-antivir-generic-cab-bypass.html">https://blog.zoller.lu/2009/04/avira-antivir-generic-cab-bypass.html</a>
28 NOV 2019
Submitted the Vulnerabiltiy Details
04 DEC 2019
AVIRA releases a patch but doesn't inform the public and/or customers.
_______________________________________________
Sent through the Full Disclosure mailing list
<a rel="nofollow" href="https://nmap.org/mailman/listinfo/fulldisclosure">https://nmap.org/mailman/listinfo/fulldisclosure</a>
Web Archives & RSS: <a rel="nofollow" href="http://seclists.org/fulldisclosure/">http://seclists.org/fulldisclosure/</a></pre>
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<h3 class="m-thread">Current thread:</h3>
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<li><strong>[TZO-19-2020] - AVIRA Generic AV Bypass (ISO Container) - CVE-2020-9320</strong> <em>Thierry Zoller (Feb 27)</em>
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