Advantech WebAccess/NMS MibbrowserTrapAddAction XML External Entity Reference Information Disclosure Vulnerability
Vulnerability Details
This vulnerability allows remote attackers to disclose sensitive information on affected installations of Advantech WebAccess/NMS. Authentication is not required to exploit this vulnerability.
The specific flaw exists within the processing of calls to the MibbrowserMibbrowserTrapAddAction method. Due to the improper restriction of XML External Entity (XXE) references, a specially crafted document specifying a URI causes the XML parser to access the URI and embed the contents back into the XML document for further processing. An attacker can leverage this vulnerability to disclose file contents in the context of SYSTEM.
Additional Details
Advantech has issued an update to correct this vulnerability. More details can be found at:
https://www.us-cert.gov/ics/advisories/icsa-20-098-01
Disclosure Timeline
- 2019-12-11 - Vulnerability reported to vendor
- 2020-04-08 - Coordinated public release of advisory
Credit
rgod of 9sg
