IETF · HTTP/2
CVE-2023-44487
HTTP/2 Rapid Reset Attack Vulnerability
What it is
The HTTP/2 protocol allows a denial of service (server resource consumption) because request cancellation can reset many streams quickly, as exploited in the wild in August through October 2023.
CISA: HTTP/2 contains a rapid reset vulnerability that allows for a distributed denial-of-service attack (DDoS).
What to do
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Deadline for US federal agencies: October 31, 2023
- Added to the CISA list
- October 10, 2023
- Published
- October 10, 2023
- Severity
- High 7.5 CVSS 3.1
- Chance of attacks in the next 30 days (EPSS)
- >99.9% in the top 0.1% of all known vulnerabilities
- Weakness
- CWE-400
- More details
- NVD · CVE.org · CISA
All references (20)
- https://github.com/dotnet/core/blob/e4613450ea0da7fd2fc6b61dfb2c1c1dec1ce9ec/release-notes/6.0/6.0.23/6.0.23.…
- https://blog.cloudflare.com/technical-breakdown-http2-rapid-reset-ddos-attack/
- https://aws.amazon.com/security/security-bulletins/AWS-2023-011/
- https://cloud.google.com/blog/products/identity-security/how-it-works-the-novel-http2-rapid-reset-ddos-attack
- https://www.nginx.com/blog/http-2-rapid-reset-attack-impacting-f5-nginx-products/
- https://cloud.google.com/blog/products/identity-security/google-cloud-mitigated-largest-ddos-attack-peaking-a…
- https://news.ycombinator.com/item?id=37831062
- https://blog.cloudflare.com/zero-day-rapid-reset-http2-record-breaking-ddos-attack/
- https://www.phoronix.com/news/HTTP2-Rapid-Reset-Attack
- https://github.com/envoyproxy/envoy/pull/30055
- https://github.com/haproxy/haproxy/issues/2312
- https://github.com/eclipse/jetty.project/issues/10679
- https://forums.swift.org/t/swift-nio-http2-security-update-cve-2023-44487-http-2-dos/67764
- https://github.com/nghttp2/nghttp2/pull/1961
- https://github.com/netty/netty/commit/58f75f665aa81a8cbcf6ffa74820042a285c5e61
- https://github.com/alibaba/tengine/issues/1872
- https://github.com/apache/tomcat/tree/main/java/org/apache/coyote/http2
- https://news.ycombinator.com/item?id=37830987
- https://news.ycombinator.com/item?id=37830998
- https://github.com/caddyserver/caddy/issues/5877
More exploited flaws from IETF
| Added | Vulnerability | Product | Severity | Attack chance |
|---|---|---|---|---|
| Nov 8, 2023 | Denial-of-Service | Service Location Protocol (SLP) | High 7.5 | 64% |
Sources: Known Exploited Vulnerabilities (CISA, public domain), CVE records (cve.org) and EPSS (FIRST). The chance of attacks is the EPSS estimate that someone will try to exploit the flaw in the next 30 days.