CVE-2017-4971: Data Binding Expression Vulnerability in Spring Web Flow

Severity

Medium

Vendor

Spring by Pivotal

Versions Affected

Spring Web Flow 2.4.0 to 2.4.4
Older unsupported versions are also affected

Description

Applications that do not change the value of the MvcViewFactoryCreator useSpringBinding property which is disabled by default (i.e. set to “false”) can be vulnerable to malicious EL expressions in view states that process form submissions but do not have a sub-element to declare explicit data binding property mappings.

Mitigation

Users of affected versions should apply the following mitigation:

2.4.x users should upgrade to 2.4.5
Note that generally it is a good practice and recommended to always use explicit data binding declarations in view states in order to prevent form submissions from setting fields on the target object that should not be set.
Spring Web Flow with JSF users are not impacted by this report.

Credit

The issue was identified by Stefano Ciccone of Gotham Digital Science

References

https://jira.spring.io/browse/SWF-1700
Commit 57f2cc on master branch (2.4.5 release)
Commit ec3d54 on 2.5.x branch (2.5.RC1 release)

History

2017-05-31: Initial vulnerability report published