- Home
- CVEs with nessus.description==Shibboleth consortium reports :
Shibboleth SP software vulnerable to additional data forgery flaws
The XML processing performed by the Service Provider software has been
found to be vulnerable to new flaws similar in nature to the one
addressed in an advisory last month.
These bugs involve the use of other XML constructs rather than entity
references, and therefore required additional mitigation once
discovered. As with the previous issue, this flaw allows for changes
to an XML document that do not break a digital signature but can alter
the user data passed through to applications behind the SP and result
in impersonation attacks and exposure of protected information.
As before, the use of XML Encryption is a significant mitigation, but
we have not dismissed the possibility that attacks on the Response
'envelope' may be possible, in both the original and this new case. No
actual attacks of this nature are known, so deployers should
prioritize patching systems that expect to handle unencrypted SAML
assertions.
An updated version of XMLTooling-C (V1.6.4) is available that protects
against these new attacks, and should help prevent similar
vulnerabilities in the future.
Unlike the previous case, these bugs are NOT prevented by any existing
Xerces-C parser version on any platform and cannot be addressed by any
means other than the updated XMLTooling-C library.
The Service Provider software relies on a generic XML parser to
process SAML responses and there are limitations in older versions of
the parser that make it impossible to fully disable Document Type
Definition (DTD) processing.
Through addition/manipulation of a DTD, it's possible to make changes
to an XML document that do not break a digital signature but are
mishandled by the SP and its libraries. These manipulations can alter
the user data passed through to applications behind the SP and result
in impersonation attacks and exposure of protected information.
While newer versions of the xerces-c3 parser are configured by the SP
into disallowing the use of a DTD via an environment variable, this
feature is not present in the xerces-c3 parser before version 3.1.4,
so an additional fix is being provided now that an actual DTD exploit
has been identified. Xerces-c3-3.1.4 was committed to the ports tree
already on 2016-07-26.
Max CVSS | 0 |
Min CVSS | 0 |
Total Count | 2 |
| ID | CVSS | Summary | Last (major) update | Published |
Back to Top
Mark selected
Back to Top