Short Name |
HTTP:CTS:ENVOY-HTTP-DOS |
---|---|
Severity |
Major |
Recommended |
No |
Recommended Action |
Drop |
Category |
HTTP |
Keywords |
Envoy HTTP Headers Denial of Service |
Release Date |
2019/12/30 |
Update Number |
3239 |
Supported Platforms |
idp-4.0+, isg-3.0+, j-series-9.5+, mx-11.4+, srx-12.1+, srx-branch-12.1+, vmx-17.4+, vsrx-12.1+, vsrx3bsd-18.2+ |
This signature detects attempts to exploit a known vulnerability against Envoy Proxy. A successful attack can result in a denial-of-service condition.
Upon receiving each incoming request header data, Envoy will iterate over existing request headers to verify that the total size of the headers stays below a maximum limit. The implementation in versions 1.10.0 through 1.11.1 for HTTP/1.x traffic and all versions of Envoy for HTTP/2 traffic had O(n^2) performance characteristics. A remote attacker may craft a request that stays below the maximum request header size but consists of many thousands of small headers to consume CPU and result in a denial-of-service attack.