=====[ Tempest Security Intelligence - ADV-01/2019 ]==========================

Avira Free Security Suite 2019 - Software Updater v2.0.6.13175
Author: Silton Santos
Tempest Security Intelligence - Recife, Pernambuco - Brazil

=====[ Table of Contents]=====================================================

* Overview
* Detailed description
* Timeline of disclosure
* Thanks & Acknowledgements
* References

=====[ Vulnerability Information]=============================================

* Class: Improper Access Control[CWE-284][1]
* CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
* CVE-2019-11396[2]

=====[ Overview]==============================================================

* System affected : Avira Free Security Suite 2019 - Software Updater[3].
* Software Version : 2.0.6.13175 (other versions may also be affected).
* Impact : An unprivileged user could obtain SYSTEM privileges.

=====[ Detailed description]==================================================

The permissive access rights on the SoftwareUpdater folder (files / folders) 
are incompatible with the privileged file manipulation performed by the product. 
Files can be created that can be used by an unprivileged user to obtain SYSTEM privileges.
Arbitrary file creation can be achieved by abusing the SwuConfig.json file creation. 
An unprivileged user can replace these files by symbolic links to arbitrary files. 
When an update occurs, a privileged service creates a file and sets its access rights,
offering write access to the Everyone group in any directory.

More Details: https://medium.com/sidechannel-br/vulnerabilidade-no-avira-security-suite-pode-levar-%C3%A0-escala%C3%A7%C3%A3o-de-privil%C3%A9gios-no-windows-71964236c077


=====[ Timeline of disclosure]===============================================

15/Apr/2019 - Responsible disclosure initiated with the vendor.
16/Apr/2019 - Vendor requested more details about the exploitation.
21/Apr/2019 - CVE assigned (reserved) CVE-2019-11396.
21/Apr/2019 - Email sent to the vendor requesting an update on the fix status.
23/Apr/2019 - The vendor has reproduced the vulnerability and works to correct it.
21/May/2019 - The vulnerability has been fixed and the vendor has informed that the release will be done in one week.
28/May/2019 - The vendor reported that the vulnerability had been fixed and that the update was public.
o4/Jun/2019 - Email sent to the vendor stating that the vulnerability has not been fixed.
18/Jun/2019 - Avira reported that the vulnerability has been fixed.
19/Jun/2019 - Email sent to the vendor stating that the vulnerability has not been fixed.
03/Jul/2019 - Avira replied that he had identified the real problem and was going to try to correct it again.
08/Jul/2019 - The vendor fixed the vulnerability.

=====[ Thanks & Acknowledgements]============================================

- Tempest Security Intelligence [4]

=====[ References ]===========================================================

[1] https://cwe.mitre.org/data/definitions/284.html

[2] https://cwe.mitre.org/data/definitions/284.html

[3] https://www.avira.com/pt-br/free-security-suite

[4] http://www.tempest.com.br

=====[ EOF ]====================================================================