Yes, the title is right. This blog covers an XML eXternal Entity (XXE) injection vulnerability that the author found in SharePoint.
The bug was recently patched by Microsoft. In general, XXE vulnerabilities are not very exciting in terms of discovery and related technical aspects. They may sometimes be fun to exploit and exfiltrate data (or do other nasty things) in real environments, but in the vulnerability research world, you typically find them, report them, and forget about them. So why the author is writing a blog post about an XXE? They have two reasons: 1. It affects SharePoint, both on-prem and cloud instances, which is a nice target. This vulnerability can be exploited by a low-privileged user. 2. This is one of the craziest XXEs that they have ever seen (and found), both in terms of vulnerability discovery and the method of triggering.
Read more…
Source: Zero Day Initiative
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