Advisory Details

October 2nd, 2018

(0Day) Wecon PIStudio xmlparser LoadXMLFile XML External Entity Processing Information Disclosure Vulnerability

ZDI-18-1106
ZDI-CAN-6162

CVE ID
CVSS SCORE 7.1, (AV:N/AC:M/Au:N/C:C/I:N/A:N)
AFFECTED VENDORS Wecon
AFFECTED PRODUCTS PIStudio
VULNERABILITY DETAILS


This vulnerability allows remote attackers to disclose sensitive information on vulnerable installations of Wecon PIStudio. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.

The specific flaw exists within the processing of project files. 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 information under the context of Administrator.

ADDITIONAL DETAILS


This vulnerability is being disclosed publicly without a patch in accordance with the ZDI 120 day deadline.

05/08/18 - ZDI sent the report to ICS-CERT
05/09/18 - ICS-CERT acknowledged, confirmed the report was sent to the vendor and sent an ICS-VU #
09/17/18 - ZDI asked ICS-CERT to confirm the report remains unpatched and to advise the vendor of the intent to publish the report as 0-day on 10/02/18

-- Mitigation:
Given the nature of the vulnerability the only salient mitigation strategy is to restrict interaction with the application to trusted files.


DISCLOSURE TIMELINE
  • 2018-05-09 - Vulnerability reported to vendor
  • 2018-10-02 - Coordinated public release of advisory
  • 2018-10-02 - Advisory Updated
CREDIT Mat Powell - Trend Micro Zero Day Initiative
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