Advisory Details

This vulnerability allows remote attackers to execute arbitrary code on affected installations of Corel PaintShop Pro. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.

The specific flaw exists within the processing of TIF files. The issue results from the lack of proper validation of user-supplied data, which can result in a write past the end of an allocated object. An attacker can leverage this vulnerability to execute code in the context of the current process.

This vulnerability is being disclosed publicly without a patch in accordance with the ZDI 120 day deadline.

11/27/19 – ZDI reported the vulnerability to the vendor
11/27/19 – The vendor acknowledged receipt and provided ticket #
12/04/19 – The vendor confirmed the issue was being looked at
01/13/20 – ZDI requested a status update
03/25/20 – ZDI notified of the intent of publishing the case as 0-day on April 2nd

-- Mitigation:
Given the nature of the vulnerability, the only salient mitigation strategy is to restrict interaction with the service to trusted machines. Only the clients and servers that have a legitimate procedural relationship with the service should be permitted to communicate with it. This could be accomplished in a number of ways, most notably with firewall rules/whitelisting.

• 2019-11-27 - Vulnerability reported to vendor
• 2020-04-02 - Coordinated public release of advisory