[TZO-17-2020] - Kaspersky Generic Archive Bypass (ZIP FLNMLEN) Feb 17 2020 10:11AM
Thierry Zoller (thierry zoller lu)

From the low-hanging-fruit-department
Kaspersky Generic Malformed Archive Bypass (ZIP Filename Length)

Release mode : Coordinated Disclosure / Patched
Ref : [TZO-17-2020] - Kaspersky Generic Archive Bypass (ZIP
Vendor : Kaspersky
Status : Patched
CVE : Unknown
Dislosure Policy:
Vendor Advisory :

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 (File Name
lenght Field) 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

IV. Patch / Advisory
Update to the respective available versions as found at

Thanks go out to Kaspersky for their cooperation in responsibly patching
and disclosing this vulnerability.

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