Summary of Vulnerability

This advisory discloses a critical severity security vulnerability in Hipchat Server. All versions of Hipchat Server before version 2.2.2 are vulnerable.

# Download the patch file
wget https://s3.amazonaws.com/hipchat-server-stable/utils/cve-2017-5638.sh
 
# Check the hash of the file
shasum cve-2017-5638.sh
md5sum cve-2017-5638.sh
 
# Make the file executable
chmod +x cve-2017-5638.sh
 
# Run the patch file
sudo dont-blame-hipchat ./cve-2017-5638.sh

Apache Struts2 Remote Code Execution (CVE-2017-5638)

Severity

Atlassian rates the severity level of this vulnerability as critical, according to the scale published in our Atlassian severity levels. The scale allows us to rank a severity as critical, high, moderate, or low.

This is an independent assessment and you should evaluate its applicability to your own IT environment.

Description

Hipchat Server includes a version of Crowd that has a version of the Apache Struts 2 library that is vulnerable to CVE-2017-5638. Attackers who have network access to a Hipchat Server instance running a vulnerable version of Hipchat Server can use this vulnerability to execute Java code of their choice and to make http requests to local & internal services.

All versions of Hipchat Server before version 2.2.2 are affected by this vulnerability.

Fix

We have taken the following steps to address these issues:

• Released a patch for customers.
• Released Hipchat Server version 2.2.2 that contains a fix for the issue.
• Released Hipchat Server version 2.2.3 that contains the latest version of Crowd and Struts2.

All versions of Hipchat Server before version 2.2.2 are affected by this vulnerability. This issue can be tracked here:  HCPUB-2801 - Getting issue details... STATUS

What You Need to Do

Upgrade (recommended)

The vulnerability and fix versions are described in the Description section above. Atlassian recommends that you upgrade to the latest version.  

Upgrade Hipchat Server to version 2.2.3 or later

Information on upgrading Hipchat Server can be found at Upgrading Hipchat Server. 

How do I check which version of Hipchat Sever I am running?

You can check which version of Hipchat Server you are running by going to https://your-server/server_admin/upgrade or by using ssh to log in to your Hipchat Server and run cat /etc/hipchat-release.

For a full description of the latest version of Hipchat Server, see the release notes.

Detection

Given that we have confirmed exploitation in the wild, we recommend customers look for signs of compromise even if they upgrade immediately. Detection of such attacks is very environment-specific but below are some indicators that customers may find useful in their investigations.

The same expression can be used across all log types, which is especially useful if you are using a SIEM or log aggregator to analyze the logs all at once:

grep -E 'InvalidContentTypeException.+multipart\/form\-data' *.log

If a remote code exploit was attempted, you will see an OGNL expression being evaluated on the server. These commands will typically start with `#cmd=` or `#cmds=` such as:

(#cmd='ls')
(#cmd='touch /tmp/thisisfine')
(#cmds=(#iswin?{'cmd.exe','/c',#cmd}:{'/bin/bash','-c',#cmd}))

Similar to Crowd, Hipchat's embedded Crowd version logs it's logs in `atlassian-crowd.log`.  The default path is `/var/log/hipchat/atlassian-crowd.log`.

017-03-08 11:21:56,410 http-bio-8095-exec-22 WARN [struts2.dispatcher.multipart.JakartaMultiPartRequest] Unable to parse request
org.apache.commons.fileupload.FileUploadBase$InvalidContentTypeException: the request doesn't contain a multipart/form-data or multipart/mixed stream, content type header is %{(#nike='multipart/form-data').(#dm=@ognl.OgnlContext@DEFAULT_MEMBER_ACCESS).(#_memberAccess?(#_memberAccess=#dm):((#container=#context['com.opensymphony.xwork2.ActionContext.container']).(#ognlUtil=#container.getInstance(@com.opensymphony.xwork2.ognl.OgnlUtil@class)).(#ognlUtil.getExcludedPackageNames().clear()).(#ognlUtil.getExcludedClasses().clear()).(#context.setMemberAccess(#dm)))).(#cmd='touch /tmp/thisisfine').(#iswin=(@java.lang.System@getProperty('os.name').toLowerCase().contains('win'))).(#cmds=(#iswin?{'cmd.exe','/c',#cmd}:{'/bin/bash','-c',#cmd})).(#p=new java.lang.ProcessBuilder(#cmds)).(#p.redirectErrorStream(true)).(#process=#p.start()).(#ros=(@org.apache.struts2.ServletActionContext@getResponse().getOutputStream())).(@org.apache.commons.io.IOUtils@copy(#process.getInputStream(),#ros)).(#ros.flush())}
...

Support

If you have questions or concerns regarding this advisory, please raise a support request at https://support.atlassian.com/customer/servicedesk-portal. 

References