Description
The W3C XML Signature Syntax and Processing (XMLDsig) specification, starting with 1.0, was originally published with a “RetrievalMethod is a URI … that may be used to obtain key and/or certificate information” statement and no accompanying information about SSRF risks, and this may have contributed to vulnerable implementations such as those discussed in CVE-2023-36661 and CVE-2024-21893. NOTE: this was mitigated in 1.1 and 2.0 via a directly referenced Best Practices document that calls on implementers to be wary of SSRF.
References
https://www.w3.org/TR/xmldsig-core2/
https://www.w3.org/TR/xmldsig-core1/
https://www.w3.org/TR/2013/NOTE-xmldsig-bestpractices-20130411/
https://www.w3.org/Signature/Drafts/WD-xmldsig-core-200003plc/
https://github.com/zmanion/Vulnerabilities/blob/main/CVE-2024-21893.md
