SRC-2020-0030 : Microsoft Exchange Server OWA OneDriveProUtilities GetWacUrl XML External Entity Processing Information Disclosure Vulnerability
CVE ID: CVE-2020-17143
CVSS Score: 8.8, (/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C)
Affected Vendors: Microsoft
Affected Products: Exchange Server
This vulnerability allows remote attackers to disclose information on affected installations of Exchange Server. Authentication is required to exploit this vulnerability.
The specific flaw exists within the processing of GetWacIframeUrlForOneDrive service commands. The issue results from the lack of proper validation of a user-supplied xml. An attacker can leverage this vulnerability to disclose information in the context of SYSTEM.
Microsoft has issued an update to correct this vulnerability. More details can be found at: https://portal.msrc.microsoft.com/security-guidance/advisory/CVE-2020-17143
2020-04-22 – Sent to Microsoft
2020-12-08 – Coordinated public release of advisory
Proof of Concept:
Credit: This vulnerability was discovered by Steven Seeley (mr_me) of Qihoo 360 Vulcan Team and Chris Anastasio