Re: [ANN] Struts 2 up to 2.3.16.1: Zero-Day Exploit Mitigation (security | critical)

[Tim <tim-security () sentinelchicken org>]

So I have to say, I feel like the Struts team is kind of... failing.
Here are my gripes:

A) I questioned the last bug fix in the thread here [1], where we
   were all reassured that it was just "ClassLoader manipulation", not 
   RCE.  Clearly that's not true.

B) The fix for the last CVE was that crappy "^class\." filter, which
   I pointed out was insufficient.  The Struts team quickly fixed
   that, but never bothered to update the "workaround" section in the 
   last advisory to the less-terrible ".*\.class\..*" regex (or whatever
   it was).  So if developers just implemented the work around from
   the advisory, they were obviously not protected.  (In hindsight,
   they never were protected even with the better regex, but was just
   irresponsible not to make the second regex more public.)

C) The Struts team is playing whack-a-mole.  Instead of fixing the
   root issue, they are just adding one blacklist regex after another,
   hoping no one figures out yet another way around it.


I urge you to take OGNL and *throw it out*.  Replace it with something
that allows only a white list of properties to be set, based on what
the application defines as relevant.  Until then, I'm recommending to
my clients that they avoid Struts like the plague.

tim

1. http://seclists.org/fulldisclosure/2014/Mar/53



On Thu, Apr 24, 2014 at 05:37:13PM +0200, Rene Gielen wrote:
> In Struts 2.3.16.1, an issue with ClassLoader manipulation via request
> parameters was supposed to be resolved. Unfortunately, the correction
> wasn't sufficient.
>
> A security fix release fully addressing this issue is in preparation and
> will be released as soon as possible.
>
> Once the release is available, all Struts 2 users are strongly
> recommended to update their installations.
>
> * Until the release is available, all Struts 2 users are strongly
> recommended to apply the mitigation described in [1] *
>
> Please follow the Apache Struts announcement channels [2][3][4][5] to
> stay updated regarding the upcoming security release. Most likely the
> release will be available within the next 72 hours. Please prepare for
> upgrading all Struts 2 based production systems to the new release
> version once available.
>
> - The Apache Struts Team.
>
> [1] http://struts.apache.org/announce.html#a20140424
> [2] http://struts.apache.org/mail.html
> [3] http://struts.apache.org/announce.html
> [4] https://plus.google.com/+ApacheStruts/posts
> [5] https://twitter.com/TheApacheStruts
>
> -- 
> René Gielen
> http://twitter.com/rgielen
>
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> http://nmap.org/mailman/listinfo/fulldisclosure
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