Active Exploitation of Zero-Day HTTP/2 Vulnerability

Security researchers have disclosed a zero-day vulnerability (CVE-2023-44487), known as Rapid Reset, in HTTP/2 protocol. The vulnerability is reportedly being actively exploited. The vulnerability has a Common Vulnerability Scoring System (CVSSv3) score of 7.5 out of 10.

The vulnerability affects all web servers which have the HTTP/2 protocol enabled.

Successful exploitation of the vulnerability could allow an attacker to cause a Distributed Denial of Service (DDoS) attack.

Organisations are advised to patch their systems to the latest versions, and also take proactive steps to mitigate the impact of DDoS attacks. Organisations may refer to SingCERT's DDoS playbook for more information on how to identify, contain and mitigate DDoS attacks: Distributed Denial-of-Service Playbook [PDF, 597 KB]

More information is available here:
https://www.cisa.gov/news-events/alerts/2023/10/10/http2-rapid-reset-vulnerability-cve-2023-44487
https://www.securityweek.com/organizations-respond-to-http-2-zero-day-exploited-for-ddos-attacks/
https://blog.talosintelligence.com/http-2-rapid-reset-ddos-attacks/
https://blog.qualys.com/vulnerabilities-threat-research/2023/10/10/cve-2023-44487-http-2-rapid-reset-attack