April 17, 2014
CDA Style Sheet Security Update CompleteA potential security vulnerability to the long-standing CDA® (Clinical Document Architecture) style sheet was recently raised and the community took quick action to update the style sheet and address each issue.
This update addresses a potential vulnerability exposed by use of the style sheet in many current internet applications by preventing malicious insertion of executable code into the display instructions for non-XML (Extensible Markup Language) clinical documents (allowed as the body in Consolidated CDA), illegal table attributes, and image URIs (uniform resource indicators) to potentially hostile sites.
- "Sanitizing" references in the nonXMLBody of a CDA document before passing it to an IFRAME.
- Removing table attributes such as "onmouseover" that are legal in XHTML but not allowed in CDA
- Allowing only local relative image URIs by default, but providing a parameter to the XSLT stylesheet to re-enable remote image support for those who need it.
The updated style sheet is available here http://gforge.hl7.org/gf/project/strucdoc/frs/?action=index.
We appreciate the action of the community to raise this issue and encourage all to continue to work to improve this utility. Special thanks to Lantana Consulting Group for working tirelessly to address these concerns quickly and efficiently.
Calvin Beebe, Diana Behling, Rick Geimer, Austin Kreisler, Patrick Loyd, and Brett Marquard
Co-Chairs, Structured Documents Work Group
It is this kind of team work that drives the best solutions for the HL7 community and we greatly appreciate the work of this Work Group and others who participated in this effort. The Technical Steering Committee will develop an ongoing security policy for HL7.
HL7 Chief Technology Officer
Technical Steering Committee Chair