OPC UA Pwn2Own 2023 Resource Exhaustion Exploit

Edit (26.05.2023): This issue is the same as CVE-2023-32787, which is published at OPC Foundation Security Bulletins.

Prosys OPC UA Simulation Server and Prosys OPC UA Browser were selected as targets at the Pwn2Own Miami 2023 ICS/SCADA-themed contest that was hosted by Zero Day Initiative (ZDI) on February 14-16, 2023. Security research teams were invited to compete for prizes for finding security exploits in various industrial control system (ICS) products, namely in the categories for OPC Unified Architecture (OPC UA) Servers, OPC UA Clients, Data Gateways, and Edge systems.

Several exploits were found from the products during the three days (see results for Day 1, Day 2 and Day 3). Prosys OPC UA Browser did not get any attacks, but Prosys OPC UA Simulation Server was successfully exploited during Day 3 when

“Claroty [Research, Team82 – Vera Mens, Noam Moshe, Uri Katz, Sharon Brizinov] used a resource exhaustion in their DoS attack against the Prosys OPC UA Simulation Server.”.

ZDI and Claroty Research disclosed the exploit’s details to us so we could fix the issue. It turned out that there were a couple of vulnerabilities in the Prosys OPC UA SDK for Java that that enabled the team to execute the attack in 5 minutes. The fix to the SDK and our other products is now available. We recommend that all our customers update their products accordingly as soon as possible and release updated versions of their products to secure the industry from this exploit in future.

We have evaluated the exploit with CVSS Base Score 7.5 and Vector String (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)

The exploit enables an unauthorized attacker to block OPC UA server applications so that they can no longer serve client applications.

The vulnerability has been given an identifier ZDI-CAN-20503.