feat: add PumbaLP/adguardhome-dot collection for DoT scanner detection

.tests/adguardhome-dot-errors/adguardhome-dot-errors.log

@@ -0,0 +1,6 @@
+2026/04/04 20:41:41.673779 [error] dnsproxy: reading msg proto=tcp err="reading len: read tcp 172.20.2.2:853->192.168.1.50:59208: read: connection reset by peer"
+2026/04/04 20:41:42.123456 [error] dnsproxy: reading msg proto=tcp err="reading len: read tcp 172.20.2.2:853->192.168.1.50:59209: read: connection reset by peer"
+2026/04/04 20:41:43.234567 [error] dnsproxy: reading msg proto=tcp err="reading len: read tcp 172.20.2.2:853->192.168.1.50:59210: read: connection reset by peer"
+2026/04/04 20:41:44.345678 [error] dnsproxy: reading msg proto=tcp err="reading len: read tcp 172.20.2.2:853->192.168.1.50:59211: read: connection reset by peer"
+2026/04/04 20:41:45.456789 [error] dnsproxy: reading msg proto=tcp err="reading len: read tcp 172.20.2.2:853->192.168.1.50:59212: read: connection reset by peer"
+2026/04/04 20:41:46.567890 [error] dnsproxy: reading msg proto=tcp err="reading len: read tcp 172.20.2.2:853->192.168.1.50:59213: read: connection reset by peer"

.tests/adguardhome-dot-errors/config.yaml

@@ -0,0 +1,7 @@
+parsers:
+  - ./parsers/s01-parse/PumbaLP/adguardhome-dot-errors.yaml
+scenarios:
+  - ./scenarios/PumbaLP/adguardhome-dot-scan.yaml
+postoverflows: []
+log_file: adguardhome-dot-errors.log
+log_type: adguardhome

.tests/adguardhome-dot-errors/parser.assert

@@ -0,0 +1,4 @@
+results["s01-parse"]["PumbaLP/adguardhome-dot-errors"][0].Success == true
+results["s01-parse"]["PumbaLP/adguardhome-dot-errors"][0].Evt.Meta["source_ip"] == "192.168.1.50"
+results["s01-parse"]["PumbaLP/adguardhome-dot-errors"][0].Evt.Meta["log_type"] == "dot_connection_reset"
+results["s01-parse"]["PumbaLP/adguardhome-dot-errors"][0].Evt.Meta["service"] == "adguardhome_dot"

.tests/adguardhome-dot-errors/scenario.assert

@@ -0,0 +1 @@
+len(results) == 0

.tests/adguardhome-dot-scan/adguardhome-dot-scan.log

@@ -0,0 +1,12 @@
+2026/04/04 20:41:41.000000 [error] dnsproxy: reading msg proto=tcp err="reading len: read tcp 172.20.2.2:853->1.2.3.4:59201: read: connection reset by peer"
+2026/04/04 20:41:42.000000 [error] dnsproxy: reading msg proto=tcp err="reading len: read tcp 172.20.2.2:853->1.2.3.4:59202: read: connection reset by peer"
+2026/04/04 20:41:43.000000 [error] dnsproxy: reading msg proto=tcp err="reading len: read tcp 172.20.2.2:853->1.2.3.4:59203: read: connection reset by peer"
+2026/04/04 20:41:44.000000 [error] dnsproxy: reading msg proto=tcp err="reading len: read tcp 172.20.2.2:853->1.2.3.4:59204: read: connection reset by peer"
+2026/04/04 20:41:45.000000 [error] dnsproxy: reading msg proto=tcp err="reading len: read tcp 172.20.2.2:853->1.2.3.4:59205: read: connection reset by peer"
+2026/04/04 20:41:46.000000 [error] dnsproxy: reading msg proto=tcp err="reading len: read tcp 172.20.2.2:853->1.2.3.4:59206: read: connection reset by peer"
+2026/04/04 20:41:41.000000 [error] dnsproxy: reading msg proto=tcp err="reading len: read tcp 172.20.2.2:853->1.2.3.4:59201: read: connection reset by peer"
+2026/04/04 20:41:42.000000 [error] dnsproxy: reading msg proto=tcp err="reading len: read tcp 172.20.2.2:853->1.2.3.4:59202: read: connection reset by peer"
+2026/04/04 20:41:43.000000 [error] dnsproxy: reading msg proto=tcp err="reading len: read tcp 172.20.2.2:853->1.2.3.4:59203: read: connection reset by peer"
+2026/04/04 20:41:44.000000 [error] dnsproxy: reading msg proto=tcp err="reading len: read tcp 172.20.2.2:853->1.2.3.4:59204: read: connection reset by peer"
+2026/04/04 20:41:45.000000 [error] dnsproxy: reading msg proto=tcp err="reading len: read tcp 172.20.2.2:853->1.2.3.4:59205: read: connection reset by peer"
+2026/04/04 20:41:46.000000 [error] dnsproxy: reading msg proto=tcp err="reading len: read tcp 172.20.2.2:853->1.2.3.4:59206: read: connection reset by peer"

.tests/adguardhome-dot-scan/config.yaml

@@ -0,0 +1,7 @@
+parsers:
+  - ./parsers/s01-parse/PumbaLP/adguardhome-dot-errors.yaml
+scenarios:
+  - ./scenarios/PumbaLP/adguardhome-dot-scan.yaml
+postoverflows: []
+log_file: adguardhome-dot-scan.log
+log_type: adguardhome

.tests/adguardhome-dot-scan/parser.assert

@@ -0,0 +1,3 @@
+len(results["s01-parse"]["PumbaLP/adguardhome-dot-errors"]) == 6
+results["s01-parse"]["PumbaLP/adguardhome-dot-errors"][0].Success == true
+results["s01-parse"]["PumbaLP/adguardhome-dot-errors"][0].Evt.Meta["source_ip"] == "192.0.2.42"

.tests/adguardhome-dot-scan/scenario.assert

@@ -0,0 +1,3 @@
+len(results) == 1
+results[0].Overflow.Alert.Source.IP == "192.0.2.42"
+results[0].Overflow.Alert.Scenario == "PumbaLP/adguardhome-dot-scan"

collections/PumbaLP/adguardhome-dot.yaml

@@ -0,0 +1,6 @@
+name: PumbaLP/adguardhome-dot
+description: "Detect and block DoT (DNS-over-TLS, port 853) scanners targeting AdGuard Home"
+parsers:
+  - PumbaLP/adguardhome-dot-errors
+scenarios:
+  - PumbaLP/adguardhome-dot-scan

parsers/s01-parse/PumbaLP/adguardhome-dot-errors.md

@@ -0,0 +1,40 @@
+# adguardhome-dot-errors
+
+Parser for AdGuard Home DoT (DNS-over-TLS, port 853) connection reset errors.
+
+## Description
+
+AdGuard Home logs connection reset errors when a client connects to port 853 (DoT) but does not complete a proper TLS handshake. This is a common indicator of port scanners and probers.
+
+This parser extracts the remote IP address and sets the `dot_connection_reset` log type for use by the `PumbaLP/adguardhome-dot-scan` scenario.
+
+## Matched log example
+
+```text
+2026/04/04 20:41:41.673779 [error] dnsproxy: reading msg proto=tcp err="reading len: read tcp 172.20.2.2:853->192.168.1.50:59208: read: connection reset by peer"
+```
+## Limitations
+
+- Only `connection reset by peer` errors contain a remote IP and are actionable.
+- Other DoT errors (TLS version mismatch, cipher suite errors, unexpected EOF) do not contain a remote IP.
+- DoQ (port 8853/udp) and direct DoH (port 443) errors also do not contain remote IPs.
+- DoH via a reverse proxy (e.g. Nginx) is covered by `crowdsecurity/nginx-logs`.
+
+## Acquisition
+
+```yaml
+source: docker
+container_name:
+  - adguardhome
+labels:
+  type: adguardhome
+```
+
+Or with log file:
+
+```yaml
+filenames:
+  - /var/log/AdGuardHome.log
+labels:
+  type: adguardhome
+```

parsers/s01-parse/PumbaLP/adguardhome-dot-errors.yaml

@@ -0,0 +1,36 @@
+name: PumbaLP/adguardhome-dot-errors
+description: "Parse AdGuard Home DoT (DNS-over-TLS, port 853) connection reset errors to detect port scanners and probers"
+#
+# Matches AdGuard Home log lines containing a remote IP address:
+# 2026/04/04 20:41:41.673779 [error] dnsproxy: reading msg proto=tcp err="reading len: read tcp 172.20.2.2:853->85.217.140.42:59208: read: connection reset by peer"
+#
+# Note: Other DoT error types (TLS version mismatch, cipher suite errors,
+# unexpected EOF, bad DNS header) do not contain a remote IP and are
+# therefore not actionable by this parser.
+#
+# Note: DoQ (port 8853/udp) and direct DoH (port 443) errors also do not
+# contain remote IPs in AdGuard Home logs and cannot be blocked this way.
+# DoH via a reverse proxy (e.g. Nginx) is covered by crowdsecurity/nginx-logs.
+#
+# Acquisition example:
+#   source: docker
+#   container_name:
+#     - adguardhome
+#   labels:
+#     type: adguardhome
+#
+filter: "evt.Line.Labels.type == 'adguardhome'"
+nodes:
+  - grok:
+      pattern: '%{YEAR:year}/%{MONTHNUM:month}/%{MONTHDAY:day} %{TIME:time} \[error\] dnsproxy: reading msg proto=tcp err="reading len: read tcp [^>]+->%{IP:remote_ip}:%{INT}: read: connection reset by peer"'
+      apply_on: message
+    onsuccess: next_stage
+    statics:
+      - meta: source_ip
+        expression: evt.Parsed.remote_ip
+      - meta: service
+        value: adguardhome_dot
+      - meta: log_type
+        value: dot_connection_reset
+      - target: evt.StrTime
+        expression: evt.Parsed.year + "/" + evt.Parsed.month + "/" + evt.Parsed.day + " " + evt.Parsed.time

scenarios/PumbaLP/adguardhome-dot-scan.md

@@ -0,0 +1,22 @@
+# adguardhome-dot-scan
+
+Detect DoT (DNS-over-TLS, port 853) scanners and probers targeting AdGuard Home.
+
+## Description
+
+A legitimate DNS-over-TLS client connects cleanly with a proper TLS handshake. Repeated connection resets from the same IP indicate a scanner or prober testing port 853 without proper TLS support.
+
+Triggers a ban after **5 connection resets within 10 minutes** from the same IP.
+
+## Requirements
+
+Requires the `PumbaLP/adguardhome-dot-errors` parser.
+
+## Tested against
+
+- AdGuard Home v0.107.x
+- Confirmed working in production (blocked real scanners)
+
+## MITRE ATT&CK
+
+- T1046 – Network Service Discovery

scenarios/PumbaLP/adguardhome-dot-scan.yaml

@@ -0,0 +1,25 @@
+type: leaky
+name: PumbaLP/adguardhome-dot-scan
+description: "Detect DoT (DNS-over-TLS, port 853) scanners and probers via repeated connection resets on AdGuard Home"
+#
+# A legitimate DNS-over-TLS client connects cleanly with a proper TLS handshake.
+# Repeated connection resets from the same IP indicate a scanner or prober
+# testing port 853 without proper TLS support.
+#
+# Capacity: 5 resets within 10 minutes triggers a ban.
+# Tested against AdGuard Home v0.107.x
+#
+filter: "evt.Meta.log_type == 'dot_connection_reset' && evt.Meta.service == 'adguardhome_dot'"
+groupby: evt.Meta.source_ip
+capacity: 5
+leakspeed: "10m"
+blackhole: 5m
+labels:
+  service: adguardhome
+  type: scan
+  spoofable: 0
+  confidence: 3
+  classification:
+    - attack.T1046
+  behavior: "network:scan"
+  remediation: true