Note: This is an archival copy of Security Sun Alert 244989 as previously published on
Latest version of this security advisory is available from as Sun Alert 1019739.1.
Article ID : 1019739.1
Article Type : Sun Alerts (SURE)
Last reviewed : 2010-01-19
Audience : PUBLIC
Copyright Notice: Copyright © 2010, Oracle Corporation and/or its affiliates.

The Java Runtime Environment (JRE) "Java Update" Mechanism Does Not Check the Digital Signature of the JRE that it Downloads


Release Phase

Bug Id

Date of Resolved Release

The Java Runtime Environment (JRE) "Java Update" Mechanism Does Not Check the Digital Signature of the JRE that it Downloads

1. Impact

The Java Runtime Environment (JRE) "Java Update" mechanism does not check the digital signature of the JRE that it downloads. This may allow a malicious file to be downloaded and installed if the DNS information that the JRE uses when checking for updates is compromised.

Sun acknowledges with thanks, Francisco Amato for bringing this issue to our attention.

2. Contributing Factors

This issue can occur in the following Java SE releases (for the Windows 32-bit release only):
  • JDK and JRE 6 Update 10 and earlier
  • JDK and JRE 5.0 Update 16 and earlier
  • SDK and JRE 1.4.2_18 and earlier

1. SDK and JRE 1.3.x is not affected.

2. The "Java Update" feature is available only on the Windows 32-bit platform. The Windows 64-bit, Solaris and Linux platforms are not affected by this issue.

To determine the default version of the JRE that Internet Explorer uses:
  1. Click "Tools" in the Menu Bar at the top of the browser
  2. Select "Sun Java Console"
The first two lines in the console display the version of Java Plug-in and JRE that Internet Explorer uses.

To determine the default version of the JRE that Mozilla or Firefox browsers use, visit the URL "about:plugins".

The browser will display a page called "Installed plug-ins" which lists the version of the Java Plug-in as in the following example:

Java(TM) Plug-in 1.5.0_11-b03

(Indicating that the JRE version the browser uses is 1.5.0_11).

3. Symptoms

There are no predictable symptoms that would indicate the described issue has been exploited.

4. Workaround

For the affected releases mentioned above, the "Automatic Update" feature of the "Java Update" mechanism can be disabled as a workaround. To disable "Automatic Update":

1. Click "Start" -> "Settings" -> "Control Panel"
2. Double-click the "Java" icon. The "Java Control Panel" appears
3. Click the "Update" tab

Note: The "Update" tab may not be available if your network administrator has disabled the "Java Update" feature during installation

4. To disable "Java Update" to automatically check for updates, un-select the "Check for Updates Automatically" check box (if checked).

Alternatively, see the Resolution section below.

5. Resolution

This issue is addressed in the following Java SE releases (for Windows 32-bit):
  • JDK and JRE 6 Update 11 or later
Note: "Java Update" currently updates JRE 5.0 and 1.4.2 releases to JRE 6. For more information on the "Java Update", see

Java SE releases are available at:

JDK 6 Update 11:

JRE 6 Update 11:

and through the Java Update tool for Microsoft Windows users.

Java SE releases SDK and JRE 1.4.2 have completed the Sun End of Service Life (EOSL) process. Sun recommends that users upgrade to the latest Java SE release. Customers interested in continuing to receive critical fixes on SDK and JRE 1.4.2 are encouraged to migrate to Java SE for Business.

For more information on Security Sun Alerts, see 1009886.1.

This Sun Alert notification is being provided to you on an "AS IS" basis. This Sun Alert notification may contain information provided by third parties. The issues described in this Sun Alert notification may or may not impact your system(s). Sun makes no representations, warranties, or guarantees as to the information contained herein. ANY AND ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT, ARE HEREBY DISCLAIMED. BY ACCESSING THIS DOCUMENT YOU ACKNOWLEDGE THAT SUN SHALL IN NO EVENT BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, PUNITIVE, OR CONSEQUENTIAL DAMAGES THAT ARISE OUT OF YOUR USE OR FAILURE TO USE THE INFORMATION CONTAINED HEREIN. This Sun Alert notification contains Sun proprietary and confidential information. It is being provided to you pursuant to the provisions of your agreement to purchase services from Sun, or, if you do not have such an agreement, the Terms of Use. This Sun Alert notification may only be used for the purposes contemplated by these agreements.

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