[TZO-05-2020] Kaspersky Generic Malformed Archive Bypass (ZIP- Compressed Size)

From: Thierry Zoller <thierry@zoller.lu>
To: fulldisclosure@seclists.org,submissions@packetstormsecurity.com,bugtraq@securityfocus.com
Cc: soc@us-cert.gov <soc@us-cert.gov>,info@circl.lu
Subject: [TZO-05-2020] Kaspersky Generic Malformed Archive Bypass (ZIP- Compressed Size)
Date:


________________________________________________________________________

                 From the low-hanging-fruit-department
      Kaspersky Generic Malformed Archive Bypass (ZIP Compressed Size)
________________________________________________________________________

Release mode    : Coordinated Disclosure
Ref             : [TZO-05-2020] - Kaspersky Generic Archive Bypass (ZIP 
Compressed Size)
Vendor          : Kaspersky
Status          : Patched
CVE             : Unknown
Dislosure Policy: https://caravelahq.com/b/policy/20949
Blog            : https://blog.zoller.lu
Vendor Advisory : 
https://support.kaspersky.com/general/vulnerability.aspx?el=12430#021219


Affected Products
=================
List of affected products
The issue affected Secure Connection product and consumer products in 
those it is incorporated:

Kaspersky Secure Connection prior to version 4.0 (2020) patch E.
Kaspersky Internet Security prior to version 2020 patch E.
Kaspersky Total Security prior to version 2020 patch E.
Kaspersky Security Cloud prior to version 2020 patch E.

Fixed versions
Kaspersky Secure Connection 4.0 (2020) patch E.
Kaspersky Internet Security 2020 patch E.
Kaspersky Total Security 2020 patch E.
Kaspersky Security Cloud 2020 patch E.


I. Background
----------------------------
Kaspersky Lab is a multinational cybersecurity and anti-virus provider 
headquartered in Moscow, Russia and operated by a holding company in the 
United Kingdom. It was founded in 1997 . Kaspersky Lab develops  and 
sells antivirus, internet security, password management, endpoint 
security, and other cybersecurity
products and services.


II. Description
----------------------------
The parsing engine supports the ZIP archive format. The parsing engine 
can be bypassed  by specifically manipulating an ZIP Archive 
(Compression Size Flag) so that it can be accessed by an end-user but 
not the Anti-Virus software. The AV engine is unable to scan the 
container and gives  the file a "clean" rating.

I may release further details after all known vulnerable vendors have 
patched their engines.


III. Impact
----------------------------
Impacts depends on the contextual use of the product and engine within 
the organisation of a customer. Gateway Products (Email, HTTP Proxy etc) 
may allow the file through unscanned and give it a clean bill of health. 
Server side AV software will not be able to discover any code or sample 
contained within this ISO file and it will not raise suspicion even  if 
you know exactly what you are looking for (Which is for example great to 
hide your implants or Exfiltration/Pivot Server).

There is a lot more to be said about this bug class, so rather than bore 
you with it in
this advisory I provide a link to my 2009 blog post
http://blog.zoller.lu/2009/04/case-for-av-bypassesevasions.html

IV. Patch / Advisory
----------------------------
Update to the respective available versions as found at
https://support.kaspersky.com/general/vulnerability.aspx?el=12430#021219


Thanks to Kaspersky for coordinating this vulnerability.





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