Add vpatch-CVE-2021-34427 rule and test (#1608)

* Add vpatch-CVE-2021-34427 rule

* Add vpatch-CVE-2021-34427 test config

* Add CVE-2021-34427.yaml test

* Add vpatch-CVE-2021-34427 rule to vpatch collection

---------

Co-authored-by: AlteredCoder <64792091+AlteredCoder@users.noreply.github.com>
Co-authored-by: Thibault "bui" Koechlin <thibault@crowdsec.net>

Author: 3 people

.appsec-tests/vpatch-CVE-2021-34427/CVE-2021-34427.yaml

@@ -0,0 +1,23 @@
+## autogenerated on 2025-12-17 14:59:35
+id: CVE-2021-34427
+info:
+  name: CVE-2021-34427
+  author: crowdsec
+  severity: info
+  description: CVE-2021-34427 testing
+  tags: appsec-testing
+http:
+  - raw:
+      - |
+        GET /document?__report=test.rptdesign&sample=%3C%25out.println(%22testfingerprint%22)%3B%25%3E&__document=./test/testfile.jsp/. HTTP/1.1
+        Host: {{Hostname}}
+
+      - |
+        GET /test/testfile.jsp HTTP/1.1
+        Host: {{Hostname}}
+
+    cookie-reuse: true
+    matchers:
+    - type: status
+      status:
+       - 403

.appsec-tests/vpatch-CVE-2021-34427/config.yaml

@@ -0,0 +1,5 @@
+## autogenerated on 2025-12-17 14:59:35
+appsec-rules:
+  - ./appsec-rules/crowdsecurity/base-config.yaml
+  - ./appsec-rules/crowdsecurity/vpatch-CVE-2021-34427.yaml
+nuclei_template: CVE-2021-34427.yaml

appsec-rules/crowdsecurity/vpatch-CVE-2021-34427.yaml

@@ -0,0 +1,45 @@
+## autogenerated on 2025-12-17 14:59:35
+name: crowdsecurity/vpatch-CVE-2021-34427
+description: 'Detects JSP injection leading to remote code execution in Eclipse BIRT Viewer via crafted query parameters.'
+rules:
+  - and:
+      - zones:
+          - URI
+        transform:
+          - lowercase
+          - urldecode
+        match:
+          type: contains
+          value: '/document'
+      - zones:
+          - ARGS
+        variables:
+          - __document
+        transform:
+          - lowercase
+          - urldecode
+        match:
+          type: contains
+          value: '.jsp/.'
+      - zones:
+          - ARGS
+        variables:
+          - sample
+        transform:
+          - lowercase
+          - urldecode
+        match:
+          type: contains
+          value: '<%'
+
+labels:
+  type: exploit
+  service: http
+  confidence: 3
+  spoofable: 0
+  behavior: 'http:exploit'
+  label: 'Eclipse BIRT - RCE'
+  classification:
+    - cve.CVE-2021-34427
+    - attack.T1190
+    - cwe.CWE-434

collections/crowdsecurity/appsec-virtual-patching.yaml

@@ -141,6 +141,7 @@ appsec-rules:
 - crowdsecurity/vpatch-CVE-2020-10987
 - crowdsecurity/vpatch-CVE-2025-55182
 - crowdsecurity/vpatch-CVE-2024-6235
+- crowdsecurity/vpatch-CVE-2021-34427
 - crowdsecurity/vpatch-CVE-2018-13317
 - crowdsecurity/vpatch-CVE-2025-9316
 - crowdsecurity/vpatch-CVE-2025-11700