Is the recent Java update of OSX (Java for OS X Lion 2012-002) to 1.6.0_31 also a bug fix for the Flashback malware?

The update is described here as:

Multiple vulnerabilities exist in Java 1.6.0_29, the most serious of which may allow an untrusted Java applet to execute arbitrary code outside the Java sandbox. Visiting a web page containing a maliciously crafted untrusted Java applet may lead to arbitrary code execution with the privileges of the current user. These issues are addressed by updating to Java version 1.6.0_31. Further information is available via the Java website at http://www.oracle.com/technetwork/java/javase/releasenotes-136954.html


3 Answers 3


It fixes the vulnerability that Flashback used to install itself; this Gizmodo article gives some more info to check:

1. Run the following command in Terminal:

defaults read /Applications/Safari.app/Contents/Info LSEnvironment

2. Take note of the value, DYLD_INSERT_LIBRARIES
3. Proceed to step 8 if you got the following error message:

"The domain/default pair of (/Applications/Safari.app/Contents/Info, LSEnvironment) does not exist"

If you don't get that error message, well, time to head to F-Secure for your fix. If you're clean so far, you can move on to step eight:

8. Run the following command in Terminal:

defaults read ~/.MacOSX/environment DYLD_INSERT_LIBRARIES

9. Take note of the result. Your system is already clean of this variant if you got an error message similar to the following:

"The domain/default pair of (/Users/joe/.MacOSX/environment, DYLD_INSERT_LIBRARIES) does not exist"

If you don't have any anti-virus protection enabled, you might want to check out the excellent (and free) Sophos Home Edition

  • please don't recommend off topic software, and anti virus for macs is a big misconception that shouldn't go without explanation
    – Alexander
    Commented Apr 6, 2012 at 20:45
  • @XAleXOwnZX What is "off topic software"? And .. what's the misconception about anti-virus? Commented Apr 7, 2012 at 13:04
  • anti virus for mac usually contains few to none mac virus signatures to check for, it's meant mainly to prevent your mac from spreading around windows viruses to friends/family etc
    – Alexander
    Commented Apr 7, 2012 at 16:09
  • @XAleXOwnZX Yet, now there's this very real Mac virus for the antivirus vendors to add to the signatures. The misconception is, therefore, obsolete? The Mac has become a victim of its own success, and is now a worthwhile target. Commented Apr 8, 2012 at 1:48
  • 2
    Actually, they don't. The Java vulnerability that Flashback exploited was patched by Oracle in February; Apple only released their own updated version a week ago. Plenty of other components of OS X are not current with their original OSS versions (rsync --version if you want a good example).
    – da4
    Commented Apr 9, 2012 at 16:29

The recent Java update from Apple fixed the current malware vulnerability. If you want even more peace of mind for future malware protection you can disable Java on your mac. You can always easily re-enable it if your program requires Java. Here are the steps to disable it on your system:

  • In Safari, go to Preferences > Security > Web Content and uncheck Enable Java.

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  • Then go to /Applications/Utilities/Java Preferences and uncheck all the checkboxes under the General tab.

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Here is a detection and removal Method from Ars Technica that works well.

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