Oracle Java 7 Security Vulnerability

National Cyber Awareness System

US-CERT Alert TA13-010A
Oracle Java 7 Security Manager Bypass Vulnerability

Original release date: January 10, 2013

Systems Affected

Any system using Oracle Java 7 (1.7, 1.7.0) including

• Java Platform Standard Edition 7 (Java SE 7)
• Java SE Development Kit (JDK 7)
• Java SE Runtime Environment (JRE 7)

All versions of Java 7 through update 10 are affected. Web browsers using the Java 7 plug-in are at high risk.

Overview

A vulnerability in the way Java 7 restricts the permissions of Java applets could allow an attacker to execute arbitrary commands on a vulnerable system.

Description

A vulnerability in the Java Security Manager allows a Java applet to grant itself permission to execute arbitrary code. An attacker could use social engineering techniques to entice a user to visit a link to a website hosting a malicious Java applet. An attacker could also compromise a legitimate web site and upload a malicious Java applet (a "drive-by download" attack).

Any web browser using the Java 7 plug-in is affected. The Java Deployment Toolkit plug-in and Java Web Start can also be used as attack vectors.

Reports indicate this vulnerability is being actively exploited, and exploit code is publicly available.

Further technical details are available in Vulnerability Note VU#625617.

Impact

By convincing a user to load a malicious Java applet or Java Network Launching Protocol (JNLP) file, an attacker could execute arbitrary code on a vulnerable system with the privileges of the Java plug-in process.

Solution

Disable Java in web browsers This and previous Java vulnerabilities have been widely targeted by attackers, and new Java vulnerabilities are likely to be discovered. To defend against this and future Java vulnerabilities, disable Java in web browsers.

Starting with Java 7 Update 10, it is possible to disable Java content in web browsers through the Java control panel applet. From Setting the Security Level of the Java Client:

For installations where the highest level of security is required, it is possible to entirely prevent any Java apps (signed or unsigned) from running in a browser by de-selecting Enable Java content in the browser in the Java Control Panel under the Security tab.

If you are unable to update to Java 7 Update 10 please see the solution section of Vulnerability Note VU#636312 for instructions on how to disable Java on a per browser basis.

References

• Vulnerability Note VU#625617
• Setting the Security Level of the Java Client
• The Security Manager
• How to disable the Java web plug-in in Safari
• How to turn off Java applets
• NoScript
• Securing Your Web Browser
• Vulnerability Note VU#636312

Revision History

January 10, 2013: Initial release

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Feedback can be directed to US-CERT Technical Staff. Please send email to with "TA13-010A Feedback VU#625617" in the subject.

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