SB2019100962 - Resource exhaustion in envoy

Description

This security bulletin contains information about 1 security vulnerability.

1) Resource exhaustion (CVE-ID: CVE-2019-15226)

The vulnerability allows a remote non-authenticated attacker to perform a denial of service (DoS) attack.

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.

Remediation

Install update from vendor's website.

References

• https://github.com/envoyproxy/envoy/commit/afc39bea36fd436e54262f150c009e8d72db5014
• https://github.com/envoyproxy/envoy/commits/master
• https://github.com/envoyproxy/envoy/issues/8520