KM03631622 - Operations Bridge Manager. Apache Tomcat vulnerability CVE-2020-1938

  • KM03631622
  • 31-Mar-2020
  • 22-Oct-2020

Summary

A vulnerability in Apache Tomcat was addressed by Operations Bridge Manager. The vulnerability could be exploited to file content disclosure of the web application or remote code execution. 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 defense-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. https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-1938

Reference

 

SUPPORT COMMUNICATION - SECURITY BULLETIN

Potential Security Impact: File content disclosure / remote code execution in Apache Tomcat

 

VULNERABILITY SUMMARY

 

A vulnerability in Apache Tomcat was addressed by Operations Bridge Manager. The vulnerability could be exploited to file content disclosure of the web application or remote code execution.

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 defense-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.

https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-1938

CVE References:

CVE-2020-1938

SUPPORTED SOFTWARE VERSIONS*: ONLY impacted versions are listed.
 

OBM Version

10.12

10.60

10.61 (2017.05)

10.62 (2017.08)

10.63 (2017.11)

10.70 (2018.05)

10.71 (2018.11)

10.80 (2019.05)

10.82 (2019.11)


Operations Bridge Manager uses the AJP Connector functionality, however it is configured to listen to the localhost/loopback device only and not accessible from remote. Therefore, the vulnerability cannot be exploited from a remote system. With additional configuration changes described below, the communication on a local system can be protected as well.


CVSS Version 3.0 and Version 2.0 Base Metrics

Reference

V3 Vector

V3 Base Score

V2 Vector

V2 Base Score

CVE-2020-1938

CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

8.4

 (AV:L/AC:L/Au:N/C:P/I:P/A:P)

7.2

 

RESOLUTION:

Micro Focus has made the following mitigation information available to resolve the vulnerability for the impacted versions of Operations Bridge Manager:

You can add a secret to the AJP configuration to enable additional protection for communication on the local system if you apply the following steps.

Step1:
Login to the machine where OBM is installed as the user under which the OBM processes are running.

Step 2:
Choose a secure value that is not easy to guess for YOUR_AJP_SECRET, it needs to be the same value in all files.

Step 3:
Add the green entries for the following files on each OBM Gateway server:

File: <OBM_HOME>/WebServer/conf/workers.properties:

worker.localAjp.secret=YOUR_AJP_SECRET

worker.wdeWorker.secret=YOUR_AJP_SECRET
 

File: <OBM_HOME>/application-server/standalone/configuration/standalone.xml:

<system-properties>

<property name="org.apache.coyote.ajp.DEFAULT_REQUIRED_SECRET" value="YOUR_AJP_SECRET"/>

</system-properties>
 

File: <OBM_HOME>/wde/conf/server.xml:

<Connector port="8010" enableLookups="false" redirectPort="8443" protocol="AJP/1.3" maxKeepAliveRequests="100" address="127.0.0.1" requiredSecret="YOUR_AJP_SECRET"/>

 

Step 4:

Add the green entry for the following file on each OBM Data Processing server:

File: <OBM_HOME>/application-server/standalone/configuration/standalone.xml:

<system-properties>

<property name="org.apache.coyote.ajp.DEFAULT_REQUIRED_SECRET" value="YOUR_AJP_SECRET"/>

</system-properties>
 

 

Step 5:

Set the file permissions so that only the owner and group can access the file
(on each Gateway server and for standalone.xml also on each DPS)

Linux:

chmod 640 <OBM_HOME>/WebServer/conf/workers.properties

chmod 640 <OBM_HOME>/wde/conf/server.xml

chmod  700 <OBM_INSTALL_DIR>/application-server/standalone/configuration

 

Windows:

icacls %TOPAZ_HOME%\WebServer\conf\workers.properties /inheritance:d /Q /C

icacls %TOPAZ_HOME%\WebServer\conf\workers.properties /remove Users /Q /C


icacls %TOPAZ_HOME%\wde\conf\server.xml /inheritance:d /Q /C

icacls %TOPAZ_HOME%\wde\conf\server.xml /remove Users /Q /C

 

icacls %TOPAZ_HOME%\application-server\standalone\configuration /inheritance:d /Q /C

 

icacls % TOPAZ_HOME %\application-server\standalone\configuration /remove Users /Q /C

 

 

Step 6:

Restart the OBM processes on each OBM Gateway server with the following commands:

Linux:

<OBM_HOME>/scripts/run_hpbsm restart

 

Windows:

<OBM_HOME>/bin/SupervisorStop.bat

<OBM_HOME>/bin/SupervisorStart.bat

 

Step 7:

Restart the application server process on each OBM Data Processing server with the following command (it just needs to be stopped; restart will happen automatically):

 

Linux:

<OBM_HOME>/bin/stop_as.sh

 

Windows:

<OBM_HOME>/bin/stop_as.bat

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