External risk intelligence

Apache Struts Remote Code Execution Vulnerability.

CVE advisoryKnown Exploit

CVE-2012-0391

A vulnerability in Apache Struts allows remote attackers to execute arbitrary Java code by exploiting how the ExceptionDelegator component handles mismatched data types. This can lead to unauthorized code execution, impacting systems processing user-provided data and posing a significant business risk.

4Halo Surface Signal

Code Injection

Apache Struts

before 2.2.3.1

External exposure likelihood

Halo Surface Signal score for CVE-2012-0391

Apache Struts is a widely used framework for building enterprise-grade, public-facing web applications. Because this vulnerability exists within the application framework itself and is triggered via standard HTTP parameters, it is commonly exposed as part of the internet-facing web interface of deployed applications.

Horizon Alert

Summary of the vulnerability and why it matters

The Apache Struts ExceptionDelegator component contains a flaw that can allow attackers to execute arbitrary Java code. This occurs when specific exception handling for mismatched data types in properties is triggered by crafted parameters. Such an exploit could lead to significant business disruption.

Vulnerable component: ExceptionDelegator in Apache Struts
Core weakness: Parameter values interpreted as OGNL expressions
Main business impact: Remote code execution and data compromise

Attack Path

How an attacker could exploit the issue

This vulnerability permits remote attackers to execute arbitrary Java code by exploiting how the ExceptionDelegator component processes mismatched data types within parameter values. When certain exceptions occur due to incorrect data types, the component interprets specific parameter values as OGNL expressions, leading to unauthorized code execution. This could impact systems processing user-provided data within affected Apache Struts applications.

Requires an exposed component.
Attacker sends crafted parameters.
Parameter triggers code execution.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability in the Apache Struts component could allow remote attackers to execute arbitrary Java code. The attack is made possible by how certain exception-handling data is interpreted. Organizations are urged to treat this as urgent due to the potential for significant business risk and the availability of public exploits.

Likely attacker skill level: Low.
Required access or conditions: None.
Business risk or urgency: High.

Priority actions

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability allows remote attackers to execute arbitrary code by exploiting how exception handling processes certain parameter values. Organizations using affected Apache Struts components should take immediate action to mitigate potential business risk. Failure to address this could lead to unauthorized access and compromise of systems and data.

Identify exposed assets.
Reduce exposure or isolate risk.
Fix, verify, and monitor.

Frequently asked questions

What is Apache Struts and its ExceptionDelegator component?

Apache Struts is a framework used for developing enterprise-level web applications. The ExceptionDelegator is a component within Struts that handles specific types of errors, particularly when data types don't match for certain properties.

What type of vulnerability is CVE-2012-0391 in Apache Struts?

CVE-2012-0391 is a critical remote code execution vulnerability. It occurs because the ExceptionDelegator component improperly interprets parameter values as OGNL expressions during certain exception handling, allowing attackers to run arbitrary Java code.

How can an attacker exploit this Apache Struts vulnerability?

An attacker can exploit this by sending specifically crafted parameters to an affected Apache Struts application. When the application encounters an exception due to mismatched data types, these crafted parameters can be interpreted as commands, leading to code execution. No special access is required for the attacker.

Who should be concerned about CVE-2012-0391?

Organizations using Apache Struts for internet-facing web applications are most at risk. This is because the vulnerability is triggered via network requests, meaning it's exposed to potential attackers on the internet. [cite: haloSurfaceSignal]

What are the first steps to address this Struts vulnerability?

To address this, first identify any Apache Struts applications that might be affected. Then, take steps to reduce their exposure or isolate them from the network if possible. The ultimate goal is to update the software to a secure version and verify the fix.

References

Written by Nicholas Merritt

External-surface CVE analysis and Halo Surface Signal prioritization for Halo Threat Intelligence.