Apache Struts 2: CVE-2020-17530: Potential RCE when using forced evaluation
Lukasz Lenart <[email protected]> Tue, 8 Dec 2020 07:55:04 +0100
| Newsgroups | gmane.comp.apache.incubator.bigtop.user,gmane.comp.security.oss.general,gmane.comp.security.bugtraq,gmane.comp.apache.maven.announce |
|---|---|
| Message-ID | <CAMopvkNhCA2dWwKMJbZjJLGD6NrxCRyZ3QOSetwdXPnGRz9mLQ__46264.948933252$1607425315$gmane$org@mail.gmail.com> |
Forced OGNL evaluation, when evaluated on raw user input in tag
attributes, may lead to remote code execution.
Problem
Some of the tag's attributes could perform a double evaluation if a
developer applied forced OGNL evaluation by using the %{...} syntax.
Using forced OGNL evaluation on untrusted user input can lead to a
Remote Code Execution and security degradation.
Solution
Avoid using forced OGNL evaluation on untrusted user input, and/or
upgrade to Struts 2.5.26 which checks if expression evaluation won't
lead to the double evaluation.
Please read our Security Bulletin for more details:
https://cwiki.apache.org/confluence/display/WW/S2-061
This vulnerability was identified by:
- Alvaro Munoz - pwntester at github dot com
- Masato Anzai of Aeye Security Lab, inc.
All developers are strongly advised to perform this action.
Kind regards
--=20
=C5=81ukasz
+ 48 606 323 122 http://www.lenart.org.pl/