AbuseIPDB scores for clients that broke a limit, within a daily budget (closes #105)

With SWWAF_ABUSEIPDB_KEY set, a client whose history counts an offence
is checked in the background, at most SWWAF_ABUSEIPDB_DAILY_BUDGET checks
a day, the count kept in reputation.json. A score at or over
SWWAF_ABUSEIPDB_MIN_SCORE is a hit for SWWAF_REPUTATION_ACTION, logged as
abuseipdb and alerted with its score. A failure or the used-up budget
gives no score and raises source_failure. The key goes only in the Key
header.

Judgement call: the budget's day is UTC; AbuseIPDB documents no reset time.
Judgement call: each check sent spends budget; a minute's pause after a failure.
Judgement call: offences are those the history counts, so far broken limits only.

Model: opus-5-5

internal/proxy/biased.go

@@ -28,18 +28,19 @@ func biasedThresholdsSet(cfg *config.Config) bool {
 
 // limitPercentages returns the client's limit percentages, for the rate
 // limits and for the byte limits, by its AS number and country as looked
-// up, each "" when unknown, and the blocklists and DNSBL zones that list
-// it. Each is the lowest of those the settings give it, the first of them
-// in the order below when several are lowest: the percentage
-// SWWAF_ASN_LIMIT_PERCENT gives its AS number, the one the file
+// up, each "" when unknown, and the blocklists, DNSBL zones and AbuseIPDB
+// that list it. Each is the lowest of those the settings give it, the
+// first of them in the order below when several are lowest: the
+// percentage SWWAF_ASN_LIMIT_PERCENT gives its AS number, the one the file
 // SWWAF_ASN_LIMIT_PERCENT_URL names gives it, the one
 // SWWAF_COUNTRY_LIMIT_PERCENT gives its country, for a client without a
 // country, SWWAF_UNKNOWN_LIMIT_PERCENT, for a client a blocklist lists,
 // the percentage of SWWAF_BLOCKLIST_ACTION while it is limit, and for a
-// client a DNSBL zone's verdict lists, the percentage of
-// SWWAF_REPUTATION_ACTION while it is limit. For the byte limits,
-// SWWAF_ASN_BYTES_PERCENT and SWWAF_COUNTRY_BYTES_PERCENT take the place
-// of the first three for an AS number or a country they list.
+// client a DNSBL zone's verdict lists, or whose AbuseIPDB score is a hit,
+// the percentage of SWWAF_REPUTATION_ACTION while it is limit. For the
+// byte limits, SWWAF_ASN_BYTES_PERCENT and SWWAF_COUNTRY_BYTES_PERCENT
+// take the place of the first three for an AS number or a country they
+// list.
 func (rq *request) limitPercentages() (percentage, percentage) {
 	cfg := rq.h.config
 	asn, country := rq.line.ASN, rq.line.Country
@@ -59,9 +60,9 @@ func (rq *request) limitPercentages() (percentage, percentage) {
 		blocklisted = percentage{cfg.BlocklistLimitPercent, "SWWAF_BLOCKLIST_ACTION"}
 	}
 
-	dnsblListed := percentage{percent: whole}
-	if rq.dnsblListed && cfg.ReputationAction == "limit" {
-		dnsblListed = percentage{cfg.ReputationLimitPercent, "SWWAF_REPUTATION_ACTION"}
+	reputationListed := percentage{percent: whole}
+	if (rq.dnsblListed || rq.abuseIPDBHit) && cfg.ReputationAction == "limit" {
+		reputationListed = percentage{cfg.ReputationLimitPercent, "SWWAF_REPUTATION_ACTION"}
 	}
 
 	asnRequests := lowest(given(cfg.ASNLimitPercent, asn, "SWWAF_ASN_LIMIT_PERCENT"),
@@ -78,8 +79,8 @@ func (rq *request) limitPercentages() (percentage, percentage) {
 		countryBytes = given(cfg.CountryBytesPercent, country, "SWWAF_COUNTRY_BYTES_PERCENT")
 	}
 
-	return lowest(asnRequests, countryRequests, unknown, blocklisted, dnsblListed),
-		lowest(asnBytes, countryBytes, unknown, blocklisted, dnsblListed)
+	return lowest(asnRequests, countryRequests, unknown, blocklisted, reputationListed),
+		lowest(asnBytes, countryBytes, unknown, blocklisted, reputationListed)
 }
 
 // given returns the percentage percents, the setting named setting, gives

internal/proxy/lookup_test.go

@@ -349,6 +349,7 @@ const unansweredGeoJSURL = "unanswered://geojs/v1/ip/geo.json"
 func TestMain(m *testing.M) {
 	transport, _ := http.DefaultTransport.(*http.Transport)
 	transport.RegisterProtocol("unanswered", unansweredGeoJS{})
+	transport.RegisterProtocol("abuseipdb", abuseIPDBStandIn{})
 
 	m.Run()
 }

internal/proxy/proxy.go

@@ -59,6 +59,9 @@ type Params struct {
 	// GeoJSURL is where clients' AS numbers and countries are looked up
 	// while SWWAF_LOOKUP_SOURCE is geojs, normally lookup.URL.
 	GeoJSURL string
+	// AbuseIPDBURL is where clients are checked with AbuseIPDB while
+	// SWWAF_ABUSEIPDB_KEY is set, normally reputation.AbuseIPDBURL.
+	AbuseIPDBURL string
 	// LookupFile is the lookup database they are looked up in while
 	// SWWAF_LOOKUP_SOURCE is file, and nil otherwise.
 	LookupFile *lookup.File
@@ -71,15 +74,17 @@ type Params struct {
 	Rules *rules.Files
 	// Alerts receive the alert for each ban the proxy makes or makes
 	// permanent, for each count over an anomaly threshold, for each request
-	// whose client a blocklist or a DNSBL zone lists, and for GeoJS failing,
-	// a fetch of a list failing or a query to a DNSBL zone failing.
+	// whose client a blocklist, a DNSBL zone or AbuseIPDB lists, and for
+	// GeoJS failing, a fetch of a list failing, a query to a DNSBL zone or
+	// a check with AbuseIPDB failing, or the day's AbuseIPDB checks used up.
 	Alerts *alerts.Queue
 }
 
 // Server is the server smallwebwaf runs, with the parts of the proxy
 // whose state the state files keep, the lookup database, nil unless
 // SWWAF_LOOKUP_SOURCE is file, the lists fetched from URLs, which its Run
-// fetches, the DNSBL zones' verdicts, and the metrics.
+// fetches, the DNSBL zones' verdicts, AbuseIPDB's scores and checks
+// spent, and the metrics.
 type Server struct {
 	*http.Server
 
@@ -90,6 +95,7 @@ type Server struct {
 	LookupFile *lookup.File
 	Lists      *reputation.Lists
 	DNSBL      *reputation.DNSBL
+	AbuseIPDB  *reputation.AbuseIPDB
 	Metrics    *metrics.Metrics
 }
 
@@ -102,7 +108,7 @@ type Server struct {
 func New(params Params) *Server {
 	errorLog := slog.NewLogLogger(params.ProcessLog.Handler(), slog.LevelWarn)
 	m := metrics.New(params.Config.MetricsTopN, params.Config.InstanceName)
-	lists, dnsbl := newReputation(params)
+	lists, dnsbl, abuseIPDB := newReputation(params, m)
 	h := &handler{
 		config:     params.Config,
 		requestLog: params.RequestLog,
@@ -140,6 +146,7 @@ func New(params Params) *Server {
 		lookupFile: params.LookupFile,
 		lists:      lists,
 		dnsbl:      dnsbl,
+		abuseIPDB:  abuseIPDB,
 		rules:      params.Rules,
 		alerts:     params.Alerts,
 	}
@@ -159,7 +166,6 @@ func New(params Params) *Server {
 	})
 	m.AddBansAndClients(h.ledger, h.limiter, params.Now)
 	m.AddRules(params.Rules)
-	m.AddReputation(h.lists, h.dnsbl)
 
 	return &Server{
 		Server: &http.Server{
@@ -181,14 +187,18 @@ func New(params Params) *Server {
 		LookupFile: h.lookupFile,
 		Lists:      h.lists,
 		DNSBL:      h.dnsbl,
+		AbuseIPDB:  h.abuseIPDB,
 		Metrics:    m,
 	}
 }
 
-// newReputation returns the lists fetched from URLs and the DNSBL zones'
-// verdicts, as the settings in params name them, with none fetched or
-// asked for yet.
-func newReputation(params Params) (*reputation.Lists, *reputation.DNSBL) {
+// newReputation returns the lists fetched from URLs, the DNSBL zones'
+// verdicts and AbuseIPDB's scores, as the settings in params name them,
+// with none fetched, asked for or checked yet, and adds their metrics to
+// m, AbuseIPDB's while SWWAF_ABUSEIPDB_KEY is set.
+func newReputation(
+	params Params, m *metrics.Metrics,
+) (*reputation.Lists, *reputation.DNSBL, *reputation.AbuseIPDB) {
 	cfg := params.Config
 	lists := reputation.New(reputation.Params{
 		BlocklistURLs: cfg.BlocklistURLs, Refresh: cfg.BlocklistRefresh,
@@ -200,8 +210,20 @@ func newReputation(params Params) (*reputation.Lists, *reputation.DNSBL) {
 		Timeout: cfg.ReputationTimeout, Now: params.Now, ProcessLog: params.ProcessLog,
 		Alerts: params.Alerts,
 	})
+	abuseIPDB := reputation.NewAbuseIPDB(reputation.AbuseIPDBParams{
+		URL: params.AbuseIPDBURL, Key: cfg.AbuseIPDBKey, MinScore: cfg.AbuseIPDBMinScore,
+		DailyBudget: cfg.AbuseIPDBDailyBudget, CacheTTL: cfg.ReputationCacheTTL,
+		Timeout: cfg.ReputationTimeout, Now: params.Now, ProcessLog: params.ProcessLog,
+		Alerts: params.Alerts,
+	})
 
-	return lists, dnsbl
+	m.AddReputation(lists, dnsbl)
+
+	if cfg.AbuseIPDBKey != "" {
+		m.AddAbuseIPDB(abuseIPDB)
+	}
+
+	return lists, dnsbl, abuseIPDB
 }
 
 // handler is the proxy. It holds what every request shares; what belongs
@@ -221,6 +243,7 @@ type handler struct {
 	lookupFile *lookup.File
 	lists      *reputation.Lists
 	dnsbl      *reputation.DNSBL
+	abuseIPDB  *reputation.AbuseIPDB
 	rules      *rules.Files
 	alerts     *alerts.Queue
 }

internal/proxy/proxy_test.go

@@ -268,7 +268,8 @@ func startProxyWithAlerts(
 // queue: they wait in it, for the test to look at. With no geojsURL, there
 // is no stand-in for GeoJS to look clients up at, and SWWAF_LOOKUP_SOURCE
 // is off unless env sets it. While it is file, the lookup database
-// SWWAF_LOOKUP_DB_PATH names is read.
+// SWWAF_LOOKUP_DB_PATH names is read. Clients are checked with AbuseIPDB
+// at abuseIPDBURL while env sets SWWAF_ABUSEIPDB_KEY.
 func newProxy(
 	t *testing.T, appURL, geojsURL string, now func() time.Time,
 	env map[string]string,
@@ -325,14 +326,15 @@ func newProxy(
 	}
 
 	server := proxy.New(proxy.Params{
-		Config:     cfg,
-		RequestLog: out,
-		ProcessLog: processLog,
-		GeoJSURL:   geojsURL,
-		LookupFile: lookupFile,
-		Now:        now,
-		Rules:      ruleFiles,
-		Alerts:     alertQueue,
+		Config:       cfg,
+		RequestLog:   out,
+		ProcessLog:   processLog,
+		GeoJSURL:     geojsURL,
+		AbuseIPDBURL: abuseIPDBURL,
+		LookupFile:   lookupFile,
+		Now:          now,
+		Rules:        ruleFiles,
+		Alerts:       alertQueue,
 	})
 
 	return server, out, alertQueue

internal/proxy/reputation.go

@@ -4,8 +4,14 @@ import (
 	"context"
 
 	"sneak.berlin/go/smallwebwaf/internal/alerts"
+	"sneak.berlin/go/smallwebwaf/internal/ratelimit"
+	"sneak.berlin/go/smallwebwaf/internal/reputation"
 )
 
+// deny is the SWWAF_BLOCKLIST_ACTION and the SWWAF_REPUTATION_ACTION that
+// refuses the requests of a client a source lists.
+const deny = "deny"
+
 // blocklistDenied notes the blocklists that list the client, as
 // noteListed does, and reports whether SWWAF_BLOCKLIST_ACTION, being deny,
 // refuses the request. Being limit, it lowers the client's limits instead
@@ -15,7 +21,7 @@ func (rq *request) blocklistDenied() bool {
 	rq.blocklisted = len(listedBy) > 0
 	rq.noteListed(listedBy, "listed by a blocklist")
 
-	return rq.blocklisted && rq.h.config.BlocklistAction == "deny"
+	return rq.blocklisted && rq.h.config.BlocklistAction == deny
 }
 
 // dnsblDenied notes the DNSBL zones whose verdict lists the client, as
@@ -30,27 +36,61 @@ func (rq *request) dnsblDenied(ctx context.Context) bool {
 	rq.dnsblListed = len(listedBy) > 0
 	rq.noteListed(listedBy, "listed by a DNSBL zone")
 
-	return rq.dnsblListed && rq.h.config.ReputationAction == "deny"
+	return rq.dnsblListed && rq.h.config.ReputationAction == deny
 }
 
-// noteListed adds sources, the URLs of the blocklists or the DNSBL zones,
-// their keys masked, that list the client, to the log line's reputation,
-// counts each of them in the metrics, and raises a reputation_hit alert,
-// with reason, for each.
-func (rq *request) noteListed(sources []string, reason string) {
-	rq.line.Reputation = append(rq.line.Reputation, sources...)
+// abuseIPDBDenied notes AbuseIPDB, as noteHit does, with the score, when
+// its score of the client is a hit, and reports whether
+// SWWAF_REPUTATION_ACTION, being deny, refuses the request, as dnsblDenied
+// does for a zone. While SWWAF_ABUSEIPDB_KEY is unset it does nothing. A
+// client without a score is checked in the background if its history
+// counts an offence, and the request does not wait for the answer. ctx is
+// the request's own context.
+func (rq *request) abuseIPDBDenied(ctx context.Context) bool {
+	if rq.h.config.AbuseIPDBKey == "" {
+		return false
+	}
 
+	held, _ := rq.h.limiter.Client(clientGroup(rq.client))
+	offender := held.History.Offences != ratelimit.Offences{}
+
+	score, hit := rq.h.abuseIPDB.Hit(ctx, rq.client, offender)
+	if !hit {
+		return false
+	}
+
+	rq.abuseIPDBHit = true
+	rq.noteHit(reputation.AbuseIPDBSource, "scored by AbuseIPDB at or over "+
+		"SWWAF_ABUSEIPDB_MIN_SCORE", map[string]any{
+		"source": reputation.AbuseIPDBSource, "score": score,
+	})
+
+	return rq.h.config.ReputationAction == deny
+}
+
+// noteListed notes each of sources, the URLs of the blocklists or the
+// DNSBL zones, their keys masked, that list the client, as noteHit does,
+// with reason, and the source in the alert's detail.
+func (rq *request) noteListed(sources []string, reason string) {
 	for _, source := range sources {
-		rq.h.metrics.ReputationHit(source)
-		rq.h.alerts.Raise(alerts.Alert{
-			Event:    alerts.EventReputationHit,
-			Client:   rq.client,
-			Netblock: clientGroup(rq.client),
-			ASN:      rq.line.ASN,
-			ASName:   rq.line.ASName,
-			Country:  rq.line.Country,
-			Reason:   reason,
-			Detail:   map[string]any{"source": source},
-		})
+		rq.noteHit(source, reason, map[string]any{"source": source})
 	}
 }
+
+// noteHit adds source, which lists the client, to the log line's
+// reputation, counts it in the metrics, and raises a reputation_hit alert
+// with reason and detail.
+func (rq *request) noteHit(source, reason string, detail map[string]any) {
+	rq.line.Reputation = append(rq.line.Reputation, source)
+	rq.h.metrics.ReputationHit(source)
+	rq.h.alerts.Raise(alerts.Alert{
+		Event:    alerts.EventReputationHit,
+		Client:   rq.client,
+		Netblock: clientGroup(rq.client),
+		ASN:      rq.line.ASN,
+		ASName:   rq.line.ASName,
+		Country:  rq.line.Country,
+		Reason:   reason,
+		Detail:   detail,
+	})
+}

internal/proxy/reputation_test.go

@@ -1,6 +1,7 @@
 package proxy_test
 
 import (
+	"io"
 	"maps"
 	"net/http"
 	"net/netip"
@@ -599,6 +600,193 @@ func TestRequestFromAClientWithoutAVerdictHasTheZoneAskedAboutIt(t *testing.T) {
 	}
 }
 
+// The AbuseIPDB settings, and accountKey, the key the tests set.
+const (
+	abuseIPDBKey = "SWWAF_ABUSEIPDB_KEY"
+	accountKey   = "abuseipdb-key-0123456789abcdef"
+)
+
+// abuseipdb is how the request log, the alerts and the metrics name
+// AbuseIPDB.
+const abuseipdb = reputation.AbuseIPDBSource
+
+// abuseIPDBURL is where newProxy has clients checked with AbuseIPDB: at
+// abuseIPDBStandIn, which TestMain registers with Go's default transport,
+// through which AbuseIPDB is asked.
+const abuseIPDBURL = "abuseipdb://stand-in/api/v2/check"
+
+// abuseIPDBStandIn is a stand-in for AbuseIPDB that gives every client the
+// score 100, at once and without the network.
+type abuseIPDBStandIn struct{}
+
+// RoundTrip answers req with the score 100.
+func (abuseIPDBStandIn) RoundTrip(req *http.Request) (*http.Response, error) {
+	return &http.Response{
+		StatusCode: http.StatusOK,
+		Status:     "200 OK",
+		Header:     http.Header{},
+		Body:       io.NopCloser(strings.NewReader(`{"data":{"abuseConfidenceScore":100}}`)),
+		Request:    req,
+	}, nil
+}
+
+func TestOnlyAClientThatHasCommittedAnOffenceIsCheckedWithAbuseIPDB(t *testing.T) {
+	t.Parallel()
+
+	forward := requestlog.ActionForward
+
+	s, clk, server, _ := startWithLookupsAndClock(t, map[string]string{
+		abuseIPDBKey: accountKey, rateLimitPerMinute: "2", reputationAction: actionLog,
+	})
+
+	// Neither fromDE, until it breaks a rate limit, nor fromKP, which never
+	// does, is checked, nor fromDE under the ban that makes.
+	s.get(fromDE, http.StatusOK, forward)
+	s.get(fromDE, http.StatusOK, forward)
+	s.get(fromKP, http.StatusOK, forward)
+	s.get(fromDE, http.StatusForbidden, requestlog.ActionRateLimited)
+	s.get(fromDE, http.StatusForbidden, requestlog.ActionBanned)
+	wantAbuseIPDBChecks(t, server, 0)
+
+	// Once the ban has ended, fromDE's first request has it checked in the
+	// background, and goes on without its score, which its next request
+	// finds.
+	clk.advance(time.Hour)
+	wantReputation(t, s.get(fromDE, http.StatusOK, forward))
+	wantAbuseIPDBChecks(t, server, 1)
+	waitUntil(func() bool { return len(server.AbuseIPDB.Snapshot().Scores) == 1 })
+	wantReputation(t, s.get(fromDE, http.StatusOK, forward), abuseipdb)
+
+	s.get(fromKP, http.StatusOK, forward)
+	wantAbuseIPDBChecks(t, server, 1)
+}
+
+func TestEachReputationActionForAClientAbuseIPDBScoresAtOrOverTheMinimum(t *testing.T) {
+	t.Parallel()
+
+	forward, denied := requestlog.ActionForward, requestlog.ActionDenied
+
+	for _, tc := range []struct {
+		action string
+		// statuses and actions are those of fromDE's three requests, and
+		// percent their limit_percent, as percentText gives it.
+		statuses []int
+		actions  []string
+		percent  string
+	}{
+		{
+			actionDeny, []int{http.StatusForbidden, http.StatusForbidden, http.StatusForbidden},
+			[]string{denied, denied, denied}, none,
+		},
+		{
+			// Half of 4 requests a minute: the third breaks the limit.
+			limitHalf, []int{http.StatusOK, http.StatusOK, http.StatusForbidden},
+			[]string{forward, forward, requestlog.ActionRateLimited},
+			"50 from " + reputationAction,
+		},
+		{
+			actionLog, []int{http.StatusOK, http.StatusOK, http.StatusOK},
+			[]string{forward, forward, forward}, none,
+		},
+	} {
+		t.Run(tc.action, func(t *testing.T) {
+			t.Parallel()
+
+			s, server, _ := startWithLookups(t, map[string]string{
+				rateLimitPerMinute: fourAMinute, abuseIPDBKey: accountKey,
+				reputationAction: tc.action,
+			})
+			// At SWWAF_ABUSEIPDB_MIN_SCORE, 75 by default, and just under it.
+			loadScores(server, map[string]int64{fromDE: 75, fromKP: 74})
+
+			for i := range 3 {
+				line := s.get(fromDE, tc.statuses[i], tc.actions[i])
+				wantReputation(t, line, abuseipdb)
+				wantPercent(t, "limit_percent", line.LimitPercent, line.LimitPercentSetting,
+					tc.percent)
+
+				// A request refused for the score is not counted.
+				counted := line.fields["counts"] != nil
+				if counted != (tc.actions[i] != denied) {
+					t.Errorf("request counted %t, logged %s", counted, tc.actions[i])
+				}
+			}
+
+			// fromKP's score is no hit, and it has the whole limit.
+			for range 3 {
+				line := s.get(fromKP, http.StatusOK, forward)
+				wantReputation(t, line)
+				wantPercent(t, "limit_percent", line.LimitPercent, line.LimitPercentSetting,
+					none)
+			}
+
+			// A refusal for the score makes no ban.
+			if held := server.Ledger.Snapshot(); tc.action == actionDeny && len(held) != 0 {
+				t.Errorf("bans %+v, want none", held)
+			}
+		})
+	}
+}
+
+func TestAbuseIPDBHitRaisesAnAlertWithTheScoreOncePerCooldownAndIsCounted(
+	t *testing.T,
+) {
+	t.Parallel()
+
+	s, server, queue := startWithLookups(t, map[string]string{
+		abuseIPDBKey: accountKey, reputationAction: actionLog, metricsToken: token,
+	})
+	loadScores(server, map[string]int64{fromDE: 90})
+
+	// The second request's alert is a repeat, which the cooldown holds back.
+	for range 2 {
+		wantReputation(t, s.get(fromDE, http.StatusOK, requestlog.ActionForward),
+			abuseipdb)
+	}
+
+	// The alert is made as a DNSBL zone's is, with the score besides.
+	waiting := queue.Snapshot().Waiting[alerts.DestinationWebhook]
+	if len(waiting) != 1 || waiting[0].Event != alerts.EventReputationHit ||
+		waiting[0].Reason != "scored by AbuseIPDB at or over SWWAF_ABUSEIPDB_MIN_SCORE" ||
+		waiting[0].Detail["source"] != abuseipdb || waiting[0].Detail["score"] != int64(90) ||
+		queue.Suppressed() != 1 {
+		t.Errorf("alerts waiting %+v, %d held back, want AbuseIPDB's reputation_hit "+
+			"with the score 90, and 1", waiting, queue.Suppressed())
+	}
+
+	// The hits, and the checks, none, since no client committed an
+	// offence, so that the whole budget is left.
+	metrics := s.scrape(unplaced)
+	labels := `{instance="` + alertInstance + `",source="` + abuseipdb + `"}`
+
+	wantMetric(t, metrics, "smallwebwaf_reputation_hits_total"+labels, 2)
+	wantMetric(t, metrics, "smallwebwaf_reputation_queries_total"+labels, 0)
+	wantMetric(t, metrics, "smallwebwaf_reputation_failures_total"+labels, 0)
+	wantMetric(t, metrics, "smallwebwaf_reputation_daily_budget_remaining"+labels, 900)
+}
+
+func TestWithoutAnAbuseIPDBKeyNoClientIsCheckedNorAScoreUsed(t *testing.T) {
+	t.Parallel()
+
+	forward := requestlog.ActionForward
+
+	s, clk, server, _ := startWithLookupsAndClock(t, map[string]string{
+		rateLimitPerMinute: "1", metricsToken: token,
+	})
+	loadScores(server, map[string]int64{fromDE: 100})
+
+	// fromDE's score is not used, and once it has committed an offence it
+	// is not checked either.
+	wantReputation(t, s.get(fromDE, http.StatusOK, forward))
+	s.get(fromDE, http.StatusForbidden, requestlog.ActionRateLimited)
+	clk.advance(time.Hour)
+	wantReputation(t, s.get(fromDE, http.StatusOK, forward))
+	wantAbuseIPDBChecks(t, server, 0)
+
+	wantNoSeries(t, s.scrape(unplaced), `smallwebwaf_reputation_daily_budget_remaining{`+
+		`instance="`+alertInstance+`",source="`+abuseipdb+`"}`)
+}
+
 // listsFetched is when loadLists has the copies fetched.
 func listsFetched() time.Time {
 	return time.Date(2026, 10, 5, 0, 0, 0, 0, time.UTC)
@@ -631,6 +819,29 @@ func loadVerdicts(server *proxy.Server, listedBy map[string][]string) {
 	server.DNSBL.Load(verdicts)
 }
 
+// loadScores puts into server's AbuseIPDB the score scores gives each
+// client, fetched at verdictsFetched, as reputation.json would at start.
+func loadScores(server *proxy.Server, scores map[string]int64) {
+	kept := make([]reputation.Score, 0, len(scores))
+	for client, score := range scores {
+		kept = append(kept, reputation.Score{
+			Client: netip.MustParseAddr(client), Score: score, Fetched: verdictsFetched(),
+		})
+	}
+
+	server.AbuseIPDB.Load(reputation.Checks{Scores: kept})
+}
+
+// wantAbuseIPDBChecks checks how many clients server has checked with
+// AbuseIPDB.
+func wantAbuseIPDBChecks(t *testing.T, server *proxy.Server, want int) {
+	t.Helper()
+
+	if got := server.AbuseIPDB.Checked(); got != want {
+		t.Errorf("%d clients checked with AbuseIPDB, want %d", got, want)
+	}
+}
+
 // loadLists puts copies of lists into server's lists, by URL, each with
 // its lines, fetched at listsFetched, as reputation.json would at start.
 func loadLists(t *testing.T, server *proxy.Server, copies map[string][]string) {

internal/proxy/request.go

@@ -64,9 +64,10 @@ type request struct {
 	counted                    bool
 	limitPercent, bytesPercent percentage
 	// blocklisted is true once a blocklist is found to list the client,
-	// and dnsblListed once a DNSBL zone's verdict is.
-	blocklisted, dnsblListed bool
-	start                    time.Time
+	// dnsblListed once a DNSBL zone's verdict is, and abuseIPDBHit once
+	// AbuseIPDB's score of it is a hit.
+	blocklisted, dnsblListed, abuseIPDBHit bool
+	start                                  time.Time
 	// checked is when the checks were done, and upstreamStart when the
 	// request was handed to the app.
 	checked       time.Time
@@ -217,13 +218,14 @@ func (rq *request) check(ctx context.Context) *refusal {
 // other client, SWWAF_DENY_NETS comes first, then a ban on its netblock,
 // so that a client either refuses is not looked up, then the lookup of
 // its AS number and country, then the country lists, then the blocklists,
-// and then the DNSBL zones' verdicts; a request any of them refuses is not
-// counted for the rate limits. Then come the rate limits, unless the
-// client is in SWWAF_RATE_LIMIT_EXEMPT_NETS or the request's path is
-// exempt under SWWAF_RATE_LIMIT_EXEMPT_PATHS, so that every other request
-// is counted, each of them by the client's limit percentages, and last the
-// rule files. A request exempt from the rate limits is exempt from the
-// byte limits too. ctx is the request's own context.
+// then the DNSBL zones' verdicts, and then AbuseIPDB's score; a request
+// any of them refuses is not counted for the rate limits. Then come the
+// rate limits, unless the client is in SWWAF_RATE_LIMIT_EXEMPT_NETS or the
+// request's path is exempt under SWWAF_RATE_LIMIT_EXEMPT_PATHS, so that
+// every other request is counted, each of them by the client's limit
+// percentages, and last the rule files. A request exempt from the rate
+// limits is exempt from the byte limits too. ctx is the request's own
+// context.
 func (rq *request) checkClient(ctx context.Context) string {
 	cfg := rq.h.config
 	if isInside(rq.client, cfg.AllowNets) {
@@ -250,7 +252,7 @@ func (rq *request) checkClient(ctx context.Context) string {
 		return requestlog.ActionDenied
 	}
 
-	if rq.dnsblDenied(ctx) {
+	if rq.dnsblDenied(ctx) || rq.abuseIPDBDenied(ctx) {
 		return requestlog.ActionDenied
 	}