opentelemetry-go-contrib is a collection of extensions for OpenTelemetry-Go. The v0.38.0 release of go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp uses the httpconv.ServerRequest function to annotate metric measurements for the http.server.request_content_length, http.server.response_content_length, and http.server.duration instruments. The ServerRequest function sets the http.target attribute value to be the whole request URI (including the query string)[^1]. The metric instruments do not forget previous measurement attributes when cumulative temporality is used, this means the cardinality of the measurements allocated is directly correlated with the unique URIs handled. If the query string is constantly random, this will result in a constant increase in memory allocation that can be used in a denial-of-service attack. This issue has been addressed in version 0.39.0. Users are advised to upgrade. There are no known workarounds for this issue.
The product does not properly control the allocation and maintenance of a limited resource.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Opentelemetry-go_contrib | Linuxfoundation | 0.38.0 (including) | 0.38.0 (including) |
| Golang-opentelemetry-contrib | Ubuntu | oracular | * |
Mitigation of resource exhaustion attacks requires that the target system either:
The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question.
The second solution is simply difficult to effectively institute – and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.