Apache Struts 2: Denial of Service -- Remote/Unauthenticated

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             AUSCERT External Security Bulletin Redistribution

                               ESB-2017.2087
           [ANN] Apache Struts: S2-049 Security Bulletin update
                              21 August 2017

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        AusCERT Security Bulletin Summary
        ---------------------------------

Product:           Apache Struts 2
Publisher:         Apache
Operating System:  UNIX variants (UNIX, Linux, OSX)
Impact/Access:     Denial of Service -- Remote/Unauthenticated
Resolution:        Patch/Upgrade
CVE Names:         CVE-2017-9787  

Original Bulletin: 
   http://struts.apache.org/docs/s2-049.html

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Apache Struts 2 Documentation
S2-049

Summary

A DoS attack is available for Spring secured actions.


Who should read this

All Struts 2 developers and users


Impact of vulnerability

A DoS attack is available for Spring secured actions.


Maximum security rating

High


Recommendation

Upgrade to Struts 2.5.12


Affected Software

Struts 2.3.7 - Struts 2.3.32, Struts 2.5 - Struts 2.5.10.1


Reporter

Yasser Zamani <yasser dot zamani at live dot com>


CVE Identifier

CVE-2017-9787


Problem

When using a Spring AOP functionality to secure Struts actions it is possible
to perform a DoS attack even if user was not properly authenticated but
an application mixed secured and not secured actions in one class.


Solution

Upgrade to Apache Struts version 2.5.12 or 2.3.33.


Backward compatibility

No backward incompatibility issues are expected.


Workaround

Please define the below constant in a struts.xml file:
<constant name="struts.additional.excludedPatterns" value=".\.accessDecisionManager\.." />

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