Headline
CVE-2022-21698: promhttp: Check validity of method and code label values by kakkoyun · Pull Request #962 · prometheus/client_golang
client_golang is the instrumentation library for Go applications in Prometheus, and the promhttp package in client_golang provides tooling around HTTP servers and clients. In client_golang prior to version 1.11.1, HTTP server is susceptible to a Denial of Service through unbounded cardinality, and potential memory exhaustion, when handling requests with non-standard HTTP methods. In order to be affected, an instrumented software must use any of promhttp.InstrumentHandler* middleware except RequestsInFlight; not filter any specific methods (e.g GET) before middleware; pass metric with method label name to our middleware; and not have any firewall/LB/proxy that filters away requests with unknown method. client_golang version 1.11.1 contains a patch for this issue. Several workarounds are available, including removing the method label name from counter/gauge used in the InstrumentHandler; turning off affected promhttp handlers; adding custom middleware before promhttp handler that will sanitize the request method given by Go http.Request; and using a reverse proxy or web application firewall, configured to only allow a limited set of methods.
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Signed-off-by: Kemal Akkoyun [email protected]
Signed-off-by: Kemal Akkoyun [email protected]
Signed-off-by: Kemal Akkoyun [email protected]
if len(additionalMethods) > 0 {
for _, method := range additionalMethods {
if strings.EqualFold(m, method) {
return strings.ToLower(m)
Signed-off-by: Kemal Akkoyun [email protected]
if s >= 100 && s <= 599 {
return strconv.Itoa(s)
}
return “unknown”
Signed-off-by: Kemal Akkoyun [email protected]
Jan 18, 2022
bwplotka added a commit that referenced this issue
Feb 15, 2022
* Check validity of method and code label values
Signed-off-by: Kemal Akkoyun [email protected]
* Use more flexibly functional option pattern for configuration
Signed-off-by: Kemal Akkoyun [email protected]
* Update documentation
Signed-off-by: Kemal Akkoyun [email protected]
* Simplify
Signed-off-by: Kemal Akkoyun [email protected]
* Fix inconsistent method naming
Signed-off-by: Kemal Akkoyun [email protected]
bwplotka added a commit that referenced this issue
Feb 15, 2022
* Check validity of method and code label values
Signed-off-by: Kemal Akkoyun [email protected]
* Use more flexibly functional option pattern for configuration
Signed-off-by: Kemal Akkoyun [email protected]
* Update documentation
Signed-off-by: Kemal Akkoyun [email protected]
* Simplify
Signed-off-by: Kemal Akkoyun [email protected]
* Fix inconsistent method naming
Signed-off-by: Kemal Akkoyun [email protected]
Co-authored-by: Kemal Akkoyun [email protected]