Stop Unnecessary Recon with a Simple JBoss Configuration Change

Cyber attacks always begin with reconnaissance. Before breaking down doors, adversaries case the digital perimeter – quietly gathering intel to plan their offensive.

One overlooked vulnerability lies in plain sight – on public-facing web servers. The "Server" field contained in HTTP response headers leaks technology specifics to any passerby.

For the popular Java application server JBoss, it may look like this by default:

Server: Apache-Coyote/1.1

This article will demonstrate why this banner poses an unnecessary exposure, how attackers leverage such leaks, and a simple configuration fix to mask sensitive details from prying eyes.

The Rise of JBoss

Let‘s begin with a quick history of the technology in question. JBoss originated in the early 2000s as JBoss Application Server (JBossAS) – an open-source, Java EE-compliant platform built to rival commercial competitors like WebLogic.

Its developer-friendly architecture combined with a low cost-base (free!) drove rapid adoption. By 2010, JBoss accounted for over 65% share in the Java app server market space.

Jboss logo

In 2006 JBoss was acquired by enterprise software giant Red Hat, further cementing its position as a market leader. It was rebranded as Red Hat JBoss Enterprise Application Platform (JBoss EAP).

Today JBoss sees widespread use across many major corporations and web properties thanks to its proven performance, vast community support, and alignment with Java standards.

Over 75% of F500 companies rely on JBoss for critical business applications.

But as usage grows, so too does the attention of potential adversaries…which brings us to our next point.

The Unnecessary Risk of Banner Exposure

The ubiquity of JBoss makes it a prime target for attackers seeking common configuration flaws or exploiting newly discovered vulnerabilities in popular software.

Cyber criminals, like lions stalking prey on the African plains, initiate reconnaissance to find the weakest point before striking.

And openly divulging the underlying technology and version hands them invaluable intel to aid their pursuit. It‘s akin to wearing an "I ❤️ JBoss 7" t-shirt with a giant arrow pointing to the login page.

hacker looking at leaked banner

Image source: Varonis

Our imaginary criminal simply takes the advertised details and plugs them into CVE databases revealing potential exploits, reports detailing critical bug fixes per past releases, or tools like Metasploit packing ready-made attack payloads.

If none exists – they will move onto lower-hanging fruit. But why give them a detailed map of attack vectors to start with if you don‘t have to?

This risk is not merely hypothetical – real world incidents have been attributed to banner intel tipping off cyber criminals:

"Attackers were able to leverage software and version details gleaned from HTTP response headers to identify vulnerable SAP deployments and carry out a series of attacks compromising 36 organizations and making over $100 million between 2018-2020"Digital Shadows Report

Many compliance standards like PCI DSS also explicitly prohibit displaying verbose server and technology banners that could empower malicious actors:

PCI DSS Requirement 2.2.2

PCI DSS Requirement 2.2.2 – Do not disclose system details in error messages or headers

Common sense suggests closing this glaring vulnerability. Now let‘s explore how with a simple JBoss tweak…

Mask Sensitive JBoss Server Banner Details

While more advanced methods exist to fully remove or dynamically alter the banner, a quick fix to mask the default banner involves config edits to standalone.conf:

1) SSH into your JBoss server shell and navigate to /bin folder

2) Open the standalone.conf file in VI or Nano

3) Find the JAVA_OPTS section and append following:

-Dorg.apache.coyote.http11.Http11Protocol.SERVER=<Your custom text here>

For example:

-Dorg.apache.coyote.http11.Http11Protocol.SERVER=SecuredJbossServer

This overrides the default Apache Coyote banner with desired replacement string.

4) Save changes and restart the JBoss process

Once back online, new HTTP requests should show your custom banner text instead:

Server: SecuredJbossServer

With this simple tweak, you:

  • Avoid openly advertising JBoss tech details
  • Comply with info disclosure standards like PCI DSS
  • Reduce attack surface visibility

But don‘t consider your work done yet…banner obscurity is merely one piece of reducing unnecessary exposure.

Going Further with JBoss Security Hardening

Though outside the scope here, be sure to conduct a full review of access controls, permissions, encryption standards, vulnerabilities, logging/auditing and other critical aspects on your JBoss instances.

Top priorities include:

  • Disabling unused components that increase attack surface like web consoles, sample apps, admin features, etc

  • Enforcing encrypted connections for all remote access

  • Keeping JBoss and all Java dependencies fully patched/updated

  • Hiding error messages that may leak stack traces

  • Installation of a Web Application Firewall (WAF) or other IPS

  • Ongoing vulnerability scanning and penetration testing

These measures coupled with an obscured server banner form a robust security baseline.

Conclusion

Leaking unnecessary details via HTTP headers allows external parties to glean insider knowledge of your technology stack. Sophisticated cyber criminals actively leverage this intel to explore vulnerabilities and sharpen attacks on widespread platforms like JBoss.

This article guided through a simple banner modification to mask the default identifier. While just one piece in a comprehensive security strategy, minimizing unnecessary disclosures is always wise from a risk-reduction standpoint.

Heed the lessons from wildlife – don‘t advertise your weaknesses lest predators exploit them. Be safe out there.