Release mode    : Silent Patch
Ref             : [TZO-20-2020] - Quickheal Malformed Archive bypass (ZIP GPFLAG)
Vendor          : Quickheal
Status          : Patched 
CVE             : CVE-2020-9362
Dislosure Policy:
Blog            :
Bug Class Info  :
Vendor Advisory : No Advisory issued, customers not informed.
Patch release   :

Affected Products
Quick Heal Total Security
Quick Heal Home Security
Quick Heal Total Security Multi-Device
Quick Heal Internet Security
Quick Heal Total Security for Mac
Quick Heal AntiVirus Pro
Quick Heal AntiVirus for Server
Quick Heal Total 
Security for Android

Enterprise versions :
- Unknown

I. Background
"Over a span of 26 years the company's R&D has focused on computer and network security solutions. The current portfolio of cloud-based security and advanced machine learning enabled solutions stop threats, attacks and malicious traffic before it strikes. This considerably reduces the system resource usage. The security solutions are indigenously developed in India. Quick Heal Antivirus Solutions, Quick Heal Scan Engine and the entire range of Quick Heal products are proprietary items of Quick Heal Technologies Ltd. (Formerly Known as Quick Heal Technologies Pvt. Ltd.)"

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

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

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
Unfortunately Quickheal has prooven unreliable partner in coordinating this vulnerability. Latest information is that this bug was fixed in November 2019. Quickheal has not provided and details on which products where affected. For enterprise customers I would recommend to reach out to quickheal
to ensure this is patched and at the same time ask for proper Security Advisories and notification.

V. Disclosure Timeline

01.10.2019 - Submitted the information
22.11.2019 - Quickheal asks me to keep this informations strictly confidential until they patched it "Once the Release is done you will be notified along with the details of the build having the fix."
09.01.2020 - ask for an update - no reply
14.01.2020 - ask for an update - inform Quickheal that unless there is an update I will disclose within the next 2 weeks. No reply
18.01.2020 - Send a reminder - no reply.  
14.02.2020 - Send a reminder - no reply.
22.02.2020 - Send a reminder - reply
Quickheal replies " In an earlier communication around November, we had intimated you that the issue has been addressed. The fix for the archive was released on 28 November, 2019 to Quick Heal users" - No they didn't.
24.02.2020 - Release of this Advisory