Threat Signal Report

CVE-2020-1938 Apache TomCat AJP File Inclusion Vulnerability

Description

FortiGuard Labs is aware of a new attack on Apache Tomcat Servers dubbed "GhostCat." Discovered by Chaitin Tech, a vulnerability in Apache Tomcat exists where an attacker has the ability to read and write in the webapp directory of Apache Tomcat. It addition to this, an attacker has the ability to upload files to the host to ultimately perform remote code execution. Assigned CVE-2020-1938, this vulnerability affects every version of Tomcat released over the past 13 years.


What are the specifics of the vulnerability?

Due to a flaw in the Apache Tomcat JServ Protocol, or AJP, a file inclusion vulnerability exists where an attacker has the ability to read and write privileges in the webapp directory of Apache Tomcat. Also, if a web application has file upload function capability; an attacker may be able to perform remote code execution by exploiting file inclusion within the vulnerability itself. Essentially, an attacker can also upload malicious JSP (JavaServer Pages) to exploit this vulnerability and gain remote code execution.


What versions of software are affected?

This affects Apache Tomcat software only. The following software versions are affected

Apache Tomcat 9.0.0.M1 to 9.0.30

Apache Tomcat 8.5.0 to 8.5.50

Apache Tomcat 7.0.0 to 7.0.99


What is the severity of this issue?

HIGH. The CVSS base score is 9.8 CRITICAL.


Has the vendor issued a patch?

Yes. The Apache Software Foundation has issued patches for versions 7/8/9 of Apache Tomcat. However, versions 6 and lower are no longer supported and have reached end of life status. Please refer to the APPENDIX section for links to patches.


What is that status of AV or IPS coverage?

Fortinet customers running the latest IPS definitions are protected against GhostCat with the following signature:

Apache.Tomcat.AJP.Local.File.Inclusion

AV coverage is not feasible for this event.


What mitigation is available if any?

It is recommended to upgrade versions that have reached end of life to one of the versions that are supported. If this is not possible, if AJP support is not necessary, disabling the connector by commenting out the server.xml /conf/server.xml file in the following line:

[Connector port = "8009" protocol = "AJP / 1.3" redirectPort = "8443" ]

If AJP connector is a requirement and cannot be commented/deactivated, then, it is recommended to configure network firewall rules to prevent unauthorized access and to make sure that the connector listens on a non-public interface.


MITRE ATT&CK

Exploit Public-Facing Application

ID: T1190

Tactic: Initial Access


Exploitation for Client Execution

ID: T1203

Tactic: Execution

Telemetry


Definitions

Traffic Light Protocol

Color When Should it Be used? How may it be shared?

TLP: RED

Not for disclosure, restricted to participants only.
Sources may use TLP:RED when information cannot be effectively acted upon by additional parties, and could lead to impacts on a party's privacy, reputation, or operations if misused. Recipients may not share TLP:RED information with any parties outside of the specific exchange, meeting, or conversation in which it was originally disclosed. In the context of a meeting, for example, TLP:RED information is limited to those present at the meeting. In most circumstances, TLP:RED should be exchanged verbally or in person.

TLP: AMBER

Limited disclosure, restricted to participants’ organizations.
Sources may use TLP:AMBER when information requires support to be effectively acted upon, yet carries risks to privacy, reputation, or operations if shared outside of the organizations involved. Recipients may only share TLP:AMBER information with members of their own organization, and with clients or customers who need to know the information to protect themselves or prevent further harm. Sources are at liberty to specify additional intended limits of the sharing: these must be adhered to.

TLP: GREEN

Limited disclosure, restricted to the community.
Sources may use TLP:GREEN when information is useful for the awareness of all participating organizations as well as with peers within the broader community or sector. Recipients may share TLP:GREEN information with peers and partner organizations within their sector or community, but not via publicly accessible channels. Information in this category can be circulated widely within a particular community. TLP:GREEN information may not be released outside of the community.

TLP: WHITE

Disclosure is not limited.
Sources may use TLP:WHITE when information carries minimal or no foreseeable risk of misuse, in accordance with applicable rules and procedures for public release. Subject to standard copyright rules, TLP:WHITE information may be distributed without restriction.